@@that1electrician yup never did that, 12-2 for receptacle and 14-2 for lighting ceiling fans and exhaust fans. One receptacle circuit per bed room and two for kitchen.
@@that1electrician Multi-Wire Branch Circuits (MWBC) are not recommended for residential applications. In part because many people like to CHEAT and use a 12/2 rope, with one phase on the black, one on white, and _the ground as a neutral!_ But, even when done right, you DO know what happens when you lose the Neutral on one, right? For those who don't know, an MWBC, properly done, is when you need two circuits, and only want to run one cable, so you put the Black on one breaker, and the Red on another, with the Neutral (Return) wire being shared by both circuits. (I hope like hell you're using a 2-Gang breaker AND 12/3! More on that in a mo'). The problem with the shared Neutral is that, if the Neutral ever gets broken, you now have 240 volts running across the appliances. Your 920 inch Samsung Big Screen has just let out the Magic Blue Smoke. Considering that Residential Electrician's wouldn't know a "Pigtail" if one bit them on the ass, and thus use the Stablocks on the receptacle as splices, all it takes is one of the receptacles early in the stream melting to interrupt the Neutral. (A pigtail is when you connect all the wires in a Junction Box together that need spliced with a wire nut [Or equivalent], with a 6" "Pigtail" coming out to feed the receptacle. This allows you to replace said receptacle later, without interrupting power to anything downstream.) And if you aren't using a 2-Gang Breaker, there's a chance that SOMEONE, somewhere, someday, will wire both conductors to the same phase. They might do this, even if you DO. And then the Neutral might be asked to carry 40 Amps back to the Breaker Panel, some day. It won't like that. Neither will your Homeowner's Insurance. And here's another reason I only carry 20 Amp Spec Grade Receptacles on my truck: Replacing 15 Amp receptacles that were used as a splice for a _20 Amp circuit!!_ When one does this, one has inserted a 15 Amp fuse in the 20 Amp circuit. This alone has made me much money. _That the client should never have had to pay!_
What you were describing at 1:45 to run 14AWG wire on a 20A circuit but just for the lighting legs of the circuit, I believe that is against code essentially everywhere, although I'd like to be proven wrong.
If 14 gauge wire is run anywhere in the circuit the breaker must be rated at 15 amps or less. If the breaker feeding a circuit is 15 amps you can mix and match 14 gauge and 12 gauge wire all you want
Agreed. This should be a code violation everywhere. The breaker is there to protect the wiring inside the walls, not the LED lights at the end. A 20A breaker must use 20A/12ga wire throughout the entire circuit (except short taps which have special rules). When someone later adds a couple of standard receptacles to the 14ga branch, it may overload the wire and not trip the 20A breaker.
I have asked this question before and my understanding is that his jurisdiction and some other commenters' jurisdictions interpret the switch leg to be a fixture wire and fall under article 402... Excerpt from uses permitted section: "for connecting luminaires to the branch-circuit conductors supplying the luminaires". This one is iffy in my opinion, I don't like it even though it is probably 'safe' I'd rather spend the extra few cents a foot and just stick with #12.
@@danlake7970 he makes constant mistakes in multiple videos. To the point that he takes the whole video down because he’s a moron. I wouldn’t trust anything he says in these videos. The fact that he has a business selling education material to people who don’t know better is near criminal since he is giving out false information that is deadly.
I think he's talking about 'in theory' only, which doesn't help electricians or anyone else cause we have to follow code. If we lived in a Mad Max world where the code rules are long gone...his point is that you can put a smaller wire on branches of a circuit and it'll still be 'safe' for that small branch lol
Something seems off in the presentation. I thought the NEC forbade running cables with smaller gauge wires than the breaker’s rating for the branch. E.g., can’t use 20 amp circuit breaker to protect a 14 gage (15 amp rated) cable. Otherwise, a shorted current of say 19 amps wouldn’t trip the breaker but it would overheat the 15 amp rated cable and potentially cause a fire. Do you have the NEC reference for this?
20 years ago, all romex was white and I thought the reason it was color coded (#12 = yellow) was to allow inspectors to easily identify what is being demonstrated in this video. I do think what is being taught in this video is low risk (since LED lighting draws small amount of current), but also would like know the NEC code allowing this practice.
I was always told NEVER to mix gauges of wire. For example, if I run a 12 gauge to an outlet off your light circuit, the 14 gauge wire would get hot in the wall, with the breaker never going to trip. A big no-no. I was told to protect the circuit for the lowest wire gauge and in your example. if you use #14 for your lights, the circuit breaker should be a 15a. Not 20a Correct?
Pretty sure you are right. If there is a fault at any point on that 14 on the 20amp circuit you will get the full fault current of a 20amp circuit and the breaker will take longer to trip potentially giving Time for that fault to create other issues
You are misunderstanding what is being said in the video. Dustin didn't say you can run 12awg to a receptacle from your lighting circuit, unless the entire wire from the circuit itself to the receptacle is 12awg, and the smaller gauge for lighting is only possible in some places where an inspector will allow it. You cannot start at a 20A breaker, go 14awg up to some lights, then 12awg down to a receptacle. It must be: 20A breaker to a receptacle with 12awg, from the receptacle to a switch at 12awg, from the switch to the light at 14awg. That 14 cannot go to anything else and must only go to the lights themselves and only after the switch. A short in the 14awg area will perform about the same as a short in the 12awg area. Both of them would draw more than 20A, and both shorts would trip the breaker. The 14awg is also still oversized to the current LED loads, but is sized correctly to the load if someone were to switch to incandescent again (though those aren't even sold any longer so you can't really do that). Per the current NEC 240.5(B)(2), you are allowed to do this for light fixture lighting.
@@LordSaliss I think you might be misunderstanding the function of an OCPD. It is a safety device. In the event of a fault where more current flows than the #14 is rated for the 20A breaker won’t protect it. It being a lightning portion of the circuit is irrelevant since the breaker is there to protect from abnormal operating conditions. (Fault)
@@LordSaliss I agree, however I have been told the circuit has #14 anywhere, the entire circuit must be protected by a 15A breaker even if you have a #12 leaving the box.
I own a duplex where they basically did this on some of the receptacles. 20A breaker with some 14awg feeding the last few receptacles. Tenant had his gaming PC setup (multiple monitors, high power pc stuff etc) and nearby baseboard heat going. The 14awg was probably drawing over the 12 amps it really ever should have been drawing. With the combination of the heat from the pc and baseboard and the overloaded wire, it melted off the receptacle. Luckily didn’t start a fire but that’s how I found out about it. I imagine a 15 amp breaker may have prevented the problem which is what I put on instead. Moral of the story, DONT MIX AND MATCH WIRE!!!
IN THEORY that is correct… the switch leg will never carry the load the home run will carry. BUT, I’m pretty sure that code wise, the conductor size must match the rating of the breaker ampacity ALL THROUGHOUT THE CIRCUIT… meaning a #14 AWG switch leg on a 20 amp circuit still violates code. I think the new standard method of new construction home wiring is to run 15 amp circuits for lighting & smoke detectors because 14/2 & 14/3 is so much cheaper… especially for travelers & smoke detector interconnect… than 12/2 & 12/3, and LEDs are so efficient anyways. LEDs just don’t require much current like old incandescent bulbs. For circuits supplying receptacles & other power, electricians use #12 AWG/20 amp circuits in new construction to accommodate appliances that draw more current. A vacuum might draw 7 amps & a space heater might draw 12 so #14 AWG/15 amp circuits can be inadequate for powering receptacles. I still don’t think that #14 AWG switch leg on a 20 amp circuit would would pass with our inspectors even if in theory what you’re saying is totally correct. There are many portions of that circuit that will not carry the full load.
Yes, by adding the 14ga anywhere you must reduce the breaker to 15amps which would reduce the total allowable load rating of all the receptacle in the circuit from his example and totally negate any possible wire cost savings, which IMO is not even a good reason as long term over the life of the service those savings are negligible pennies a day for a better gauge wire. This video was good in theory but not in practice.
Woah. But if the homeowner goes screwing in a bunch of old incandescent bulbs, or one of those screw-in adapters that turns a light socket into a receptacle, or a cheap light fails in a weird way that draws too much power but isn't a dead short, then it's entirely possible to overload that 14AWG wire if it's on a 20A breaker. Is the breaker meant to protect the wiring or isn't it?
My quite non-professional interpretation: If you're connecting can lights with sockets, that's a consideration; but the new LED luminaires don't have sockets for the lamps, so there's no way to connect an incandescent lamp to them. As for Dustin's comment that you could theoretically use tiny wire because the LEDs draw so little current, I was wondering about electrical fault danger, too. Seems like that wire could get dangerously hot, and provide enough resistance as to not draw the full trip amperage of the breaker. Would love to know if this is a legitimate concern.
@@soundman1402 I thought about this a lot (have not gone to the code book yet) but how about this.....Regardless of 12 or 14 awg going to the LED fixture, (or even incandescent for that matter), the fixture itself is internally wired with 18awg so this is the lightest gauge wire on either a 20A or 15A breaker.
First of all, if you have 14AWG anywhere in the branch circuit, the maximum breaker size is 15A. Even still, a lamp holder like you're describing isn't a luminaire per the code, so you can't rely on a particular low-power bulb being installed in it to reduce the load calculations. You'd have to assume that someone might install the most powerful possible bulb and plan accordingly.
Ya, just like Dustin said you could use something crazy small, like coax or audio cable, he does close with using code or better. He's a decent advocate for minding/reducing voltage drop as well, which is generally only obtainable by 'oversizing' cable on the best new branch circuits.
First and foremost I want to thank you for taking your time to post these videos. I appreciate them deeper than you know. I'm one of those "ADHD" guys and I went to the electrician's apprenticeship at 37 years old. I learn best by hands on. And the apprenticeship I went through was well over 90% book work or computer. I went through it in the middle of the pandemic too so a lot of stuff was on zoom as well. Completely horrible for an ADHD brain like mine. I learn best by physically doing the work and then going back and seeing how it works because that makes it more interesting for my brain. I passed my apprenticeship a little above average but not by much and half of that was because I found the answers to a lot of my homework so I didn't end up doing a lot of it. Which also didn't help retaining any kind of knowledge. But now that I've been in the field working, I'm going back and watching these videos. It's like the puzzle pieces of my brain are finally falling into place. I'm a solid electrician when it comes to my work. It's always clean and it is always correct. But to have the understanding behind everything allows my troubleshooting skills to get that much better and to explain things a little bit better to the people around me when I'm doing my work. So again thank you for these posts.
You sound a lot like the way I understand things. So If my home has existing 12-2, can I connect 14-2 for a bathroom light, bathroom fan and, one out let?
Great explanation. After working with cheap #18 luminary wire behind a fixture that breaks, I'd rather stick with something larger. Plus, if they repurpose the circuit for a vent fan or warming light they will need the current. Never cheat code, always go above the minimum.
I teach HAM radio licensing classes and the parallel / series differences in voltage and amperage is one of the hardest things for students to wrap their heads around. Excellent use of visual aids to show how it works.
Wire is sized for the breaker it's on, regardless of the load that may be on it. If the 14 AWG romex somehow gets cut on a can light housing or the LED fixture goes bad, and that draws a heavy load without shorting, the wire will get too hot before a 20A breaker trips at 27+ amps.
This is exactly why I watched this video, we have new code inspectors, that I don't trust their knowledge, since they don't seem to have any experience at all. So now I need to figure out of I'm going to run a home run of 14/2 for all the lights and fans, or run 12/3 to 20 lights and two ceiling fans. From what I got out of his video that is fine, but I was still 2nd guessing the idea. Normally I run 12/2 for all 120v runs, since I have a bunch of rentals, and you never know when the tenants are going to try and heat the whole hose with space heaters. But this is for my house, and hate to waste that much 12/2 and 12/3 for a bunch of LED lights. IMO this video needs taken down, because from what I got out of the video it is fine to run a 20 amp breaker, then 12/2 to the outlets, then branch 14/2 off that.. but NEC 240.4(D)(3) says different. Well time to see how many spots I have left on the breaker panel.. that sucker is starting to run short, and not running them silly mini doubles.
@maxjankowski6892 15a outlets are the same internally as 20s, minus the extra tab for a 20a plug, so daisy chaining 15s on 12awg wire on a 20a breaker is okay. It could get a melty neutral slot if someone managed to draw near 20a through one of the duplex outlets. I've seen that with an old window air conditioner that was running very inefficiently, and a space heater connected to a short appliance extention cord causing extra resistance.
Great video as always! You mentioned LED on Ethernet cable; I received approval from my inspector to run all LED lights throughout the house, to be connected to a “separate” 12v powered panel with Ethernet cable. My wife and I are renovating a 1910 Farmhouse, excited to see this project through.
I completely disagree. If you have a 20 amps breaker, code does not allow you to reduce conductor size based on actual load except in very very specific situations. The idea being that if you have an overload (say a high impedance short circuit) in the circuit and you have reduced the conductor, it may melt before the cb trips. By sizing all conductors according to upstream protection you prevent this situation from happening
Yeah that was my immediate thought; what clears the fault on the LED leg before the wire melts? In principal it'd be safe if that leg had an additional fuse or something but IDK if there's even code for that.
Plus once you start mixing different gauge wires and splicing things together it all becomes a mess to deal with for any future person making repairs or modifications.
I changed my position on this. I am not worried about a sharp short-circuit condition that would cause 100s or even 1000s of amps to flow in the circuit. A 20A cb magnetic protection would trip instantenously and clear the fault and limit the total energy (Amps x Time) below the allowable thermal envelope of both 12AWG and 14AWG wires. I am worried about overloads or high impedence faults, which would limit the fault current to lower levels (between 15 and 20ish Amps), which takes the cb much much longer to clear and could generate too much energy and melt a 14AWG wire. Now, are there jurisdictions that consider the situation of such a fault happening unlikely enough for lighting legs that they build exceptions into local codes for reducing conductor size to 14AWG on a 20A breaker? Yes, I believe that is likely. I would still prefer feeing the lighting circuit from a 15A breaker though.
@@philibertperusse8998 What about a fault condition that doesn't draw 100's of amps, but somewhere between 15 and 20? And is not detected for years, could that cause overheating in the 14-gauge wire and eventual breakdown of the insulation?
I worked with a maintenance guy who installed 12 to every outlet every time. 🤔 His theory was surprisingly rational. The buildings were built in the 1960s and there weren’t even remotely enough electrical outlets. As such he expected that any outlet he installed would have multiple extension cords and port multipliers added and so the circuit should naturally be capable of supporting the expected load.
By me, the only time 12 gets used on a 15A circuit is on really long homeruns to guard against voltage drop. And I never use 14 on a 20A circuit. We use 12 gauge(20A), for kitchen receptacles, bath receptacles, laundry receptacles, dining receptacles, and garage receptacles. Everything else gets 14 gauge(15A).
The cost difference when considering the better wire over the life of the system translates to pennies for a much better product long term. Same goes with using the higher quality 20amp receptacle outlets over the cheap homeowner grade 15amp outlets.
Got a question for you, if you can give me a sneer that’s be cool! If you are installing a receptacle to a small commercial tv store should you be using 14 AWG or 12 AWG? Is there any specific code for it or do you follow the amps the receptacle you’re adding needs? (For example if I’m adding a 15 amp recep I use 14AWG because that’s rated for the 15A)?
In Canada, 14 gauge (15 amps) is commonly used for majority of homes outlet and lighting circuits, usually combind for individual rooms. 12 gauge(20 amps) is required for kitchens/dinning rooms, bathrooms, utility rooms and garages.
I have lived in Alabama my whole life. I purchase a newly built home in 2008. The wiring in that home was exactly as you described in Canada. I recently moved, buying a home built in 1985. I have seen some really janky wiring. Bedrooms have 15A and 14/2 Romex. But lighting and outlets are all on the same circuits. Additionally, they put the furnace/air handler on the same circuit as some outlets in the Main BR and the bathroom lighting. Plus, half the kitchen is on the same circuit as the dining room, basement stairwell and garage. Half the living room is on the same circuit as the basement lighting (separate from garage lighting), while the other half is on the same circuit is on the same circuit as the outside floods and the garage outlets (also separate from the garage lighting). Still, as janky as all that is, it isn't as janky as the house I grew up in, which was built in 1954. Let's just say that when I saw how the house was wired, I thank God each day that we all didn't die in a house fire growing up.
@@DGTubbs Lol. Well don’t go into any houses built before world war ll. You will probably run down the street screaming. Houses are built to the code of that Era. The Code across the country is on a 3 year change cycle. So I’m sure your 2008 home is not in compliance with current code. Neither is my Custom built home from 1980. Nothing to worry about. Just maintain it and don’t do any thing Janky. Lol.
WOW to you! I'm learning about running wire in my bathroom for an additional light which has 3 LED lights. You are the only one video I've watched that really explained things to me in the way I understand. Thanks for sharing
The only thing I see wrong here is if you put 14/2 onto a circuit that has a 12/2 home run and is fed by a 20-amp breaker, you’re actually not in compliance because all the cabling that comes off a 20-amp breaker needs to be rated for 20 amps.
I have asked this question before and my understanding is that his jurisdiction and some other commenters' jurisdictions interpret the switch leg to be a fixture wire and fall under article 402... Excerpt from uses permitted section: "for connecting luminaires to the branch-circuit conductors supplying the luminaires". This one is iffy in my opinion, I don't like it even though it is probably 'safe' I'd rather spend the extra few cents a foot and just stick with #12.
LED lighting is a pain in ass to connect with larger than 14awg. The connection box is so small.. and i dont know why. So, for lighting, use 15A breakers. And outlets, use 12/2 just in case you decide to change your 15A outlets to 15-20A outlets.
Except working w 12 sucks wiener compared to 14. Pretty sure it falls under the fixture wires code section (I think someone else said 402). Just run lighting on a 15 amp breaker and then you’re safe.
My new home (2 years old) in Georgia used all 15 amp AFCI breakers and 14 gauge wire on all lighting and receptical circuits (except for dedicated, 20A recepticals like microwave, cloths washer, etc.).
Interesting debate watching from the sidelines of non-trade but activtly intereted community. Looking forward to seeing where this ends up. 99/100 dustin gives us top notch content. And who knows what oddities are in different codes. Right or wrong, looking forward to being educated!
I don't think this is what you intended, but this video comes across as claiming you can run 14ga on a 20a breaker depending on the intended load. Which would be really bad if the intended load changed to something not intended. You should clarify.
Great explanation. I live in an old house. Some circuits have been upgraded to 12/2, while some receptacles are still K&T, unfortunately. I'm trying to add a receptacle in Kitchen, inside cabinet, powers only the electronics for stove/range and the exhaust fan/hood lighting. I was going to use 14/2 for the additional receptscle, but the one I'm tying into is 12/2. I've decided to go 12/2, to match existing conditions. One thing I see is that the existing 12/2 Romex has Green insulation/jacket of Ground wire. I cannot seem to find 12/2 Romex wirh Green insulation/jacket on ground wire, only bare ground wire... Have they stopped coating Romex ground wire with green jackets now?
My mind is blown. I thought you can’t run wires rated below the OCPD. If something goes wrong (even though it’s not going to happen) and those lights draw 16 amps, that 1AWG is going to heat up. Have I been wrong this whole time? I can maybe see what you’re saying if it was a low voltage system with a transformer involved. Otherwise I’m going to be looking into this for the next 6 months trying to convince myself it’s ok lol.
You're correct. I just spent over an hour reading the NEC researching this, and basically: 20A circuit = #12 wire or larger only. #14 wire = 15A breaker only. There are some exceptions, but none of them apply to running Romex to light fixtures. Fixture wires and tap conductors that run no more than 18" from a junction box to the fixture can be #14 or smaller, but anything beyond that has to be sized to the breaker.
As an electrical engineer, It's not the way I would ever design a circuit released into the wild. Although you might get away with it without killing anyone if you have an AFCI breaker on the line.
Thanks for clarifying. I could still see using it on cabinet lighting that was 12 volts but I wouldn’t want that on a 20A breaker either. Would AFCI possibly save you from killing someone because it should trip before a condition is met that would cause it to draw more than 15 amps? Because I’m thinking if for some reason it draws 16 amps without an arc the 20A AFCI is going to let the wire heat up. Obviously this is becoming academic now.
@@doc13067 And you would be correct. The "electrical engineer" you responded to proves the case that most engineers don't know jack about what they are talking about. The AFCI protects against ARC FAULTS, NOT OVERCURRENT which is the main issue. The ONLY way an AFCI would be of benefit is IF the overcurrent finally melted the wire enough to start an arc fault, which the AFCI MIGHT clear. But by that point, enough heat would have been generated to start a fire. Mr. Engineer needs to learn how the real world works, and crack open a Code Book AND learn about Ohm's Law and current ampacities of materials.
Man, I don’t know if it’s how you explain it but it makes so much sense. I appreciate the content and the time you take to explain it visuals, it jumps makes it easier to understand. Keep the great content coming. I find super informative.
It’s funny, cuz in places like the UK, they do undersize the wire, and add an additional overcurrent protection on the smaller wire branch. That’s also why their plugs are so big, they have to have fuses in them so they don’t overload the building wire. There is low voltage lighting systems with smaller wiring, and even lighting that runs off of power over Ethernet now. Seems like we should start having mini “sub panels” where we run 12 2 to a room, then have a “mini panel” with 1 amp breakers and smaller wiring for “low amp” lighting circuits.
Bro I know all this. Learned it quite some time ago. I can’t tell you how invaluable these videos are. New info, new insight, refreshers, different methods. It’s all great stuff and I encourage you to keep it coming!
If i understood correctly you used 12 gauge on everything before the LED lights and ran a 14 gauge leg for the LED and that 2nd receptacle.. so without that 16 amp load you essentially said use the correct load for your breaker?
Glad to see a lot of concern in the comments, reinforces my confusion watching the video. I am not an electrician but I've done a little research for DIY purposes. My understanding: 12-gauge wire needs 20-amp breaker protection, 14-gauge wire needs 15-amp breaker protection. Running 14-gauge wire anywhere in a circuit that is connected to a 20-amp breaker is a no-no because 14-gauge wire is only rated for 15 amps, so if there is some sort of fault condition in the circuit that draws more than 15 amps but less than 20 amps you could have a potential fire hazard.
Makes sense that you could run #14 off a switch leg. Also it's easier to identify the light wires at a glance vs having to test for your hot feed. I think they recommend 12-2 all round is to simplify safety verification. No chance of an overheat due to resistance. Though like you said, smaller would carry the load. I mean most fixtures only have like 18 or 20 gauge strand or solid in them. So that's automatic resistance right there. But, it's contained. Where your lines run tacked to wooden studs and joists. Potential heat absorbers. And, if someone gets heavy on the hammer with a staple, it could be a potential fire later. My daughter had an outlet with a toaster plugged into it that kept tripping the breaker. I pulled the box, checked the wiring, the outlet, found nothing. Went to the panel and looking, spotted nothing. But when I pulled the breaker, whomever stripped the wire at the breaker cut almost all the way through the wire. So when the toaster ran for several minutes the wire got so hot it kicked the breaker. So, in the famous words of the Borg, resistance is futile .
14 is allowed here in Oregon, and is actually used more here for lighting circuits. Most lighting nowadays is LED and the load is less than it ever has been. There is even a provision in the new NEC for a new 10 amp breaker. Wether or not Manufacturers pick this up, is yet to be seen. If you are running a mile or more of wire, 14 can be quite a cost savings. Thanks, Russ 28 years in the Trade.
Back in the days of incandescent lights and plug in the vacuum cleaners, bigger wires meant brighter lights and stronger vacuums. With LEDs and cordless electric, the demands on those circuits are much lower. Still remember to oversize the car charger, dryer, and range circuits. Reducing the voltage drop will save the customer thousands of dollars over the life of the home.
I totally see what you’re saying. But those cordless battery powered vacs will never compare to a plug in the wall vac. I have one of those cordless vacs and, to get the same suction as it’s corded counterpart from the same brand, I have to put it on “boost” mode. That gives me maybe 10-15 minutes of vac time before the battery is completely depleted. Who wants to vac for 10 mins and then charge for 4 hours to get another 10min of vac time? It’s like electric vehicles. Waste of time.
@@miket5506 Guess it just depends on how much floor you have. 🤷♂ I have a lawn service. 5 years ago I would not have even entertained the idea of cordless electric OPT. Now all my equipment is battery electric. It was just a matter of solving the refueling problem. Having said that, I agree, there are some battery powered tools out there that only belong in the discount stores where cheep people buy cheep merch.
The drain pump on my Whirlpool washing machine is fed by 21AWG from the factory with a factory vampire wire piercing connection for termination. The bean-counters probably got a nice Christmas Bonus for sizing the wire "just right". The vampire connection caused the wire to corrode and fall off the pump. That's how I found this ingenious bit of engineering.
I like this how it shows parallel bs series and such. What’s even better to teach people to understand it is make them wire single then eventually dual voice coil speakers that are different ohm and amps that can handle a wide load of ohms but of course deliver there max at there lowest possible ohms. It really gives you an understanding even tho it’s DC
Just learned more about parallel circuits in 8 minutes than I did the entire month we spent on dc theory in my union dc theory course. But my instructor was also more obsessed with his 20% fail quota he was trying to reach…. The way he teaches it’s no wonder 20% of his students fail first year.
It's good stuff, but do note the breaker is the safety for every device AND the cable of the circuit, so actually do use the cable coded. While yes, a shorter run of 14awg will perform just as well as a longer run of 12awg at 20a, and be safer, it's still codified as a no-go. Use this info to help reduce voltage drop! Meaning, to upsize certain runs, like the home runs with devices on pigtailed smaller awg 'twig' circuits. The professional who just wants to use the minimum required, do the minimum, just pass inspection; worries far less about the circuit's use and voltage drop, and more about the few dollars saved.
One of the differences between Canada and the US is use of 12/2. For residential homes almost all circuits are 14/2, 15A circuits. Those 20A circuits that you guys use are rare here, at least in homes built ten years ago. I find that particularly irritating in my garages over the years. Some power tools like my table saw are right at the limit of 15 A circuits, and old homes share lighting with power outlets. Add in the voltage drop from panel to garage, and the table saw needs to spike current higher (and longer) to spool up. That's a recipe for a blown circuit breaker.
There is only one question. Is the breaker going to trip before the wire in your wall heats up and starts a fire? Technically you can have 1 amp circuit on 14/2, but if you put that on a 20 amp breaker, and anything goes wrong with your LEDs, your breaker may not trip before you have a real problem.
Correct. Though probably not with a dual function breaker. Should cover that 'something.' But that's why Dustin says use code, says the common minimums, and shows the NEX table for cable size vs circuit protection size.
Question on parallel ckt example where it is mentioned branch circuits could use smaller size wire if loads are small. How would the smaller wires sized ckts be protected from a SHORT condition in the branch? I would think 20A would be sourced from the main panel and burn the wires that could not handle the current.
In my company, if we are doing a remodel or service call and find 14awg wiring on a 20 amp breaker, we will ALWAYS downsize the breaker to a 15 amp one or upsize the wire. You never know what may have changed in an older home.
I believe the code should be lighting =14/2 or (12/2 optional) and all plug receptacles 12/2 regardless… just my opinion. I see too many people for all the items they plug in these days overloading more 14/2 receptacles than 12/2 receptacles… nice video as always dustin…👍👍👍
If I was to reinvent the wheel tomorrow, I'd want homeruns to run in attics or basements, with essentially pigtailed 'twig' circuits down/up to devices. The homeruns would be oversized, to 10awg for circuits with receptacles, though pigtailed out to receptacles with 12awg. Less in walls, more access, safer with receptacles pigtailed, and easier to modify like adding new receptacles/other devices.
Even if planning on LED, if installing an E26 socket device requires we use Maximum of the rating in box. We still have to use 12 on lights because of this.
Think he was talking the directly wired LED fixtures. It would feel ridiculous to be running 12awg just to get to each light and use their cheap push-connect fittings to splice to tiny ~20awg wire and to draw ~10w. Code is bureaucracy, and the actual goal of any bureaucracy is survival, not their propaganda message as to what their mission is. It's rarely very efficient, usually adds needless cost, and long term makes what they control overall worse and eventually unaffordable.
I ran my entire home in 12/2, it's weird, lots of people said "Good call", still lots of people said "You know you could have used 14/2 for the lights right?". Since it's my home, I like being able to turn off entire rooms. Voltage drop was a big concern for me, as I have a 130' home, and even though the breaker boxes are centralized, some homeruns were around 100' long in places.
So, I ran a voltage drop calculation using 14 gauge wire, I had to assume a couple of things of course because I do not know your house layout. Assuming, you have a 100' run, with 30 75-watt equivalent LEDs (13W actual power draw), you would draw roughly 3.3 amps. Ran through a simple voltage drop calculation, you would only lose ~2 Volts which is a 1.6% loss, which is negligible and would not affect the circuit much at all, if I remember correctly you want to be +/- 5% and I put a lot of lights on that particular circuit, generally, lighting layouts are divided up more. In general, with certain exceptions, voltage drop in residential homes is negligible and rarely comes up. It's not unheard of, but usually it doesn't affect the run. Nothing wrong with what you did, just food for thought.
@@TheRiddler491 Thanks for that, I know it doesn't usually come up, however my rental house before that had bad voltage drop on one end of the home. It annoyed me, and others greatly! I wanted to do whatever I could to prevent it. Also, my actual circuit could be longer than 100', once you account for the rest of the circuit. Strangely enough, after all that, my led lights fluctuate in brightness when my washer is swishing around the water. I think that is more bum led lights.
The cost difference is not much when you consider the 30+ years of service. I ran 12/2 for everything in my house as well. Same with the receptacles, commercial grade 20 amp outlets. Again the cost difference over the life of the product makes it a no brainer.
@@raterus Interesting, did you wire your house? I find it odd that they would fluctuate after the unit is running. Could be shit LED's but I assume they are not on the same circuit. You see it a lot in older homes where your turn on the microwave and the lights dim because they are on the same circuit. As far as your old apartment, they probably tied a bunch of things together which could cause lights to dim. If you have a bunch of things on one circuit, this could also cause voltage to drop as it is electrical pressure much like turning on all the water sources in your home. The demand exceeds supply, causing voltage loss. Voltage loss only really happens in extreme distances and is considered for such things as parking lot lights and such. There are many factors to consider here aside from distance.
In some California apartment buildings 3 decades ago the only place where 14 awg was allowed was the sole circuit to the smoke alarm.. All else was 12 awg since you assumed the tenants would do crazy stuff. Lol. Liability The breaker for the 1.5 ton ac compressor on the roof was 10awg for most apartments..
I’m ready to overcome my fear of installing two 20 amp circuits for my garage. Currently it’s on 15 amp for interior and exterior lights and outlets with 12/2, 12/3, 10/2 and 14/2 Romex including for two 3 way switches in a double gang box. There’s no way an electrician wired this unless they were visually blind. I purchased 12/3 & 12/2 Romax. Do I wire the circuits with the 12/3 or 12/2. Where does the red wire go in the panel. I’ve seen videos only explaining the ground, white and hot black wire.
Personally, if I was building a house right now, I'd go with 12/2 everywhere, just because you don't know how you're going to use the house in the future. A little extra headroom feels like a good idea. I'd bet that upgrading even just one branch at a later date is going to cost more than the difference of using 12/2 versus 14/2. 12/2 is harder to work with, though.
@@ericschulze5641 In my case, we have a home office with four relatively high-end computers, a laser printer, and a 3D printer all on one circuit. Add a space heater and it's pushing tripping the breaker.
I knew a guy whose father cut sheet metal with tin snips for US Steel his whole career. I also served in the Reserve with a guy whose civilian job was as a commercial electrician, who only ever worked with 12 AWG wire. I shook each man's hand once. After that, they only got knuckle bumps from me.
@@vaska916 I just got back from a job yesterday with two pieces of scrap that prove you're wrong. They were 15A, El Cheapo Contractor Specials, on 12 gauge with a 15A breaker. They were replaced with Spec Grade 20A's. It's a Rental. The cheaper you go in a Rental, _the quicker it's going to break._
This video could've been 2 minutes long. As long as you're installing a 15A breaker (and your AHJ allows 15A circuits), then yes you can use #14 wire, because #14 copper can handle 15A (240.4(D)(4)). If you're running a 20A circuit, then you MUST use #12 (or larger) wire. There are exceptions, but none of them apply to running Romex to light fixtures. EVERY section of wire must be at least #12, even if it's just feeding a single light fixture.
@@phi5head And I disagree with him. I read all of the code sections he mentioned in the video, and nothing in any of those sections says that you can run #14 to light fixtures on a 20A circuit. I'm more than willing to admit I'm wrong if someone points out a code section that says otherwise.
@@jonclark1288 It doesn't make sense to me. i can understand if it's a 15A breaker. #12 to the outlets to prevent voltage drop, and #14 to lights since under normal loads they draw very little power. But even then, I rather have #12 go to the lights since I've had issues with LEDs flickering when the voltage drops slightly. Also don't have to worry about how much of what # wire you have, just buy #12 and forget about it.
Maybe 40 years ago in my area you were allowed to run 14/2 from a wall case that had a switch to control ceiling lights that were feed off a 12 guage 20 amp circuit breaker but no longer.
I had a situation where someone plugged in a 16 gauge device that had shorted leads, only the circuit breaker was a 30 amp breaker. The circuit breaker didn't trip, but the 16 gauge wire disintegrated at the plug. This is the main reason why I only run 14 gauge wire and use 15 amp breakers for lighting. If something goes wrong with the lighting on small gauge wire or a lamp failure, there is a better chance of the breaker tripping with the wire being only one size smaller. By the way, the only way I could fix the 30 amp receptacles problem was to use a spare hot on a different leg that was already in the same conduit but had to share the neutral and use a two pole 20 amp breaker. Both circuits remained contained in the same Wiremold Plugmold power strip that provided odd receptacles on one leg and the even receptacles on the other.
While fixture whips can be undersized there is no provision allowing what you described. You can't just refer generally to three different sections none of which say what you want. NM is not a "fixture wire."
Thanks for talking about this. I was even thinking of requesting it a few months ago. I've been really appreciating the design of circuits lately. Not getting crazy, but definitely reducing voltage drop as much as practical. Even doing 10/2 main runs with 12/2 or 14/2 off of them when practical. I'll need to read more in to when I'm still allowed to use 14/2 on 20a circuits if for specific devices. Was under impression that 20a means 14/2 is vorbotten, but maybe not. Will look. And will look for 240v as well, as a lot of the 240v I've done really did have low amp devices with short, harder to run, final circuits from main run.
@@imtheonevanhalen1557 A device's wiring can be less. On dedicated 'hard' wiring, there's argument to be made for where that wiring begins, best I've heard. Reason, the wiring in most devices is significantly smaller. I feel a little disappointed and defeated when I oversize the conductors for a circuit only to be slicing to something like 16ga. But I know it's because those wires are short enough to be fine. Most power cords are also 14ga or much smaller. But it's also a lot easier to splice some 14ga to fish up through a floor to a baseboard heater than has 16ga wire inside it to splice to. Also, 240v. Lol
Here is a DIY question for ya......How can you tell what gauge the wire is if it is not part of the original package with description. I have some old wire in my garage. I know it is electrical wire and not CAT5 patch or anything like that. The wire looks white shielded just like in this video but the wire does not have any markings on the shielding that I can discern. Thoughts?
I'm running a outlet to my crawlspace a 15 amp GFCI outlet from a kitchen outlet that never gets used . What size wire should I run the outlet with ? Any help would be appreciated.! The outlet is to run a dehumidifier and a condensation pump and 60 cfm exhaust fan .
This fails to account for a wiring fault (such as critters chewing the insulation) or an overload situation that could cause 14ga to get too hot and start a fire. You can’t put 14ga on a 20a breaker no matter how you want to spin it!
This is an unrelated question but is it ok to use 12 ga THWN stranded wire in underground pvc conduit, or do I need to use a direct bury rated flat 12/2 w/g cable?
I have a light on the wall of a small room that has a 14/2 wire, my question is if I can draw electricity to put an outlet on that line of light? Or is it dangerous to connect a 12/2 wire to a 14/2 light?
The only way I can see getting into trouble with the whiteboard drawing, is if there is a short in the lighting circuit. Now you have a failure event and the breaker is not sensitive enough to protect it. Of course it will trip for a dead short. Will it trip for a lesser but still very dangerous failure?
I've had this question about extension cords. I'm using my dad's old extension cord and it's from the 80s and I didn't see any markings on it. I have no idea what size it is. I ended up buying a 25' 12/3 simply because they said it could handle 20 amps and it has 3 plugs on it. Doubt I'll ever use that much but I feel better knowing I've got a good one now.
When i recently rewired my house i ran 12/2 on 20amp breakers for power and 14/2 on 15amp breakers for lights. Two breakers for each room. Everything was inspected without issues.
homeowner here, probably going further into the rabbit hole than i need to (just want to replace an outlet in bedroom), but you could, theoretically, use 12/2 whenever you could use 14/2, right? just not vice versa?
I'm retired and shocked over high price of copper wire. Think the first 250' box of 12/2 NM cable that I purchased was only $12. Always ran 12/2 to each bedroom but still think the NEC should follow you to run 14/2 to luminaries especially since they are now LED'S consuming less then 1 amp. Heard they want 14/2 copper clad aluminum cable be installed to tree luminares and be in a maximum of a 10 amp circuit breaker.
On a circuit with a dual function breaker, yep; but otherwise the breaker has to be sized to protect everything when things go wrong, including the cable, so it's more about sizing the breaker/fuse protection to the circuit cable and devices rather than the other way around (like we normally think of it).
What happens when you get a short in one of those 14-gauge light circuits on the 20 Amp breaker? Possibility of 14-gauge wiring melting / fire before the breaker reacts?
Wow, that was confusing and conflicting information about circuitry and ampacity. You have to use correct overcurrent protection for the smallest size wire on a branch circuit, so combining 12cu and 14cu is not recommended or legal. Unless your loads on the 14gauge wire is on the load side of a low voltage driver and/or transformer
I kept all lighting circuits separate from receptacle circuit when I wired my house. 15a breakers and 14ga wire. Every single light inside and outside my home adds up to like 2 amps.
Of course with the vast # of exemptions you are allowed to have a 14 guage line feeding a dedicated motor load such as a air compressor or air conditioner on a 20 amp circuit breaker to prevent a 15 amp breaker from tripping due to locked rotor current during start up. Same with a #12 guage wire can be feed from a 25 or 30 amp breaker. If you had a mansion with a fire pump breaker would be very high.
I will never use 12/2 Romex for lighting in any type of residential application. I really can care less what the authority having jurisdiction aka the inspector has to say about it. Because the inspectors job is to make sure we did our job up to the NEC. Inspector is not there to make up his own rules which many of them tried to do.
My house was built in 1983. Second owner. All wiring to the breaker panel is 12/3 (or bigger for 220v circuits). There is *NO 14/3 ga* wire anywhere in the house. *Does that mean* if i want to install 6 LED wafer lights and tie in to an existing 12 ga wire that I *CAN NOT* use 14 ga...
@Electrician U If i am running a bedroom can i put the lights (LED) on 14/2 & also add my receptacles with 12/2 as long as I run 12/2 straight to the panel??
I run lighting circuits on 15A branches on 14 AWG. Receptacles all go in 20A branches, even though they're only required in specific places like kitchens. Putting 14 AWG on a 20A overcurrent-protected circuit? You need to conform to the tap conductor requirements in Article 240. 16 and 18 AWG? Only on fixture wiring as defined in the NEC.
Guy I worked with he said high frequency switching power supplies can cause harmonics on the neutral wire get enough of those on a shared neutral overload it.
Very informative video. Can you maybe demo how to correctly split off different gauge wires in these types of a setup? Is there a certain way that has to be followed to join different gauge wires together for the different circuits. For example -Are separate junction boxes needed when changing gauge - different from the ones that the switch or receptacle would reside in? I always thought it was bad to join different gauge wires together but this explains the theory how it can be safe in certain instances. Note - I am no electrician just your typical DIY type.
12 ga. minimum in my truck, and all receptacles are spec grade. I HATE being called back because someone melted a receptacle by plugging 2 space heaters into it. It';s also nice to not have to carry 45 more line items of inventory.
@@TimeSurfer206 exactly. Have all your material the same trade size and make your installation future safe. You never know what these people are going to do after you leave.
So, are you saying that in that particular parallel circuit that I could take 14/2 from the switch up to and through all the lights? I was always under the impression that if I started a circuit with say 12/2 I could not down size the wire size on the circuit
Use only the size cable the nec writes as minimum for whatever circuit/home run you are pulling. Only recommend pulling many extra circuits/home runs. Like one to the garage door openers.
Do you think NEC will change to mandate more receptacles? And power supply? Based on how everything is moving to electric: lawn equipment, cars, table saws & tools, E-bikes & scooters, all our electronic crap that needs charging- the whole gas stove debacle and heat pumps. It seems we need more than "one receptacle every 6 feet". Maybe a double duplex receptacle at every spot?
The short answer is yes. It takes time. The NEC now requires at least one receptacle outlet for each vehicle bay in the dwelling garage. This is due to the increase in the use of rechargeable batteries.
I used 12 everywhere in my house. I could have used 14, but I already had the spool of 12 there. If you ever want to put in a ceiling fan, It's a good idea to run 12. I might have saved a little bit with 14, but the cost difference was negligible.
Exactly, the cost difference long term becomes negligible and you get a much better wire for the life of the service. Same goes for using the higher quality commercial grade 20 amp receptacle outlets.
Actually, if you're doing a ceiling fan, you should run a 14/3 so you can separate the light and the fan at the switch box. Also you can get rid of those ugly pull chains. Absolutely NOT a 12/2 unless you are coming off a 20 amp circuit to be code worthy. There is absolutely no reason to run a 12 wire for a ceiling fan. Unless you have 16 or 18 of them on the same circuit. Most residential ceiling fans only draw 1 to a .5 of an amp.
The problem would arise if there was a malfunction in the device installed. In the case of a short it will start pushing more current all the way up to 20A before tripping the 20A breaker on a 15A wire. Now you are over rating that wire by 5A. Please explain how that is a good or acceptable thing. Not all shorts are dead shorts causing the breaker to trip immediately.
I ran 12/2 to all my outlets even when they are on 15 amp breakers.. but coming off the outlets that are also servicing lights, I run 14/2 .. everything coming out of my panel goes down below into my crawl space then up to the outlet ,back down into crawl space, back up to next outlet.. I have virtually no horizontal runs inside my walls.. (except where im powering a switch for lights, and that is only in the cavity on the other side of the same stud. ) I never put a 20 amp breaker to a 15 amp outlet .. really wasn't that much extra to run the heavier wire to all the bottoms..
That’s a good point about lights. You could run like a hundred LEDs on 18 gauge. They should really make smaller gauges of romex for these applications. Does code have any provision for this?
A sub panel or breaker/fused shutoff box. Circuit protection (breaker/fuse) needs to be sized to the circuit. Code includes using all items to their UL listing and as described to be used by the manufacturer. Sizing the circuit breaker includes determining cable size (and mfg amp ratings) and the maximum device protection listed for each device on the circuit. A receptacle will be listed simply as '15A' but an air conditioning condenser unit will really spell it out on the tag with "Maximum breaker/fuse/protection: 30A." I don't know recall seeing, and don't want to go check, if cable has a max amp rating. I'm sure they do list it somewhere. But cable is more amps vs length/distance/resistance... so it's simply codified as minimums. With enough distance, and voltage drop resistance and heat, with select amps, you could easily burn a place down following code.
My grandfather, who I apprenticed under, used to do it this way, 14awg switch leg on 20 amp circuit. Although theoretically okay, I would highly advise against it. Talk with your AHJ. It's very easy for an inspector to call this out and fail you. NEC makes it pretty clear not to put 14awg anywhere on a 20A circuit
Son just bought an old house in Portland with 100 amp service. Electrician quoted him 5200.00 to upgrade to 220. ? What is the procedure that would cost so much? Cheers. Ken
I am wondering how many electricians worry about voltage drop. The tester I used for testing boat 120VAC outlets imposed a momentary 15A load and showed me the voltage drop. On 100'ers, the voltage drop with 14 gauge wire and a 15A breaker was often in excess of 27%. And owners were wondering why their high draw motors kept failing prematurely. In my wife's custom built home the outlets furthest from the breaker box in the bedrooms had voltage drops of 15-20%. I am of the opinion that unless it is a circuit solely dedicated to lighting, all wiring in a house should be 12 gauge minimum!
I always ran separate 15 amp circuits to the lights and 20 amps to receptacle circuits. Blow a receptacle breaker the lights stay on
How do you feel about MWBCs? Do you just avoid those altogether as well? I do.
@@that1electrician yup never did that, 12-2 for receptacle and 14-2 for lighting ceiling fans and exhaust fans. One receptacle circuit per bed room and two for kitchen.
@@that1electrician Multi-Wire Branch Circuits (MWBC) are not recommended for residential applications. In part because many people like to CHEAT and use a 12/2 rope, with one phase on the black, one on white, and _the ground as a neutral!_
But, even when done right, you DO know what happens when you lose the Neutral on one, right?
For those who don't know, an MWBC, properly done, is when you need two circuits, and only want to run one cable, so you put the Black on one breaker, and the Red on another, with the Neutral (Return) wire being shared by both circuits. (I hope like hell you're using a 2-Gang breaker AND 12/3! More on that in a mo').
The problem with the shared Neutral is that, if the Neutral ever gets broken, you now have 240 volts running across the appliances. Your 920 inch Samsung Big Screen has just let out the Magic Blue Smoke. Considering that Residential Electrician's wouldn't know a "Pigtail" if one bit them on the ass, and thus use the Stablocks on the receptacle as splices, all it takes is one of the receptacles early in the stream melting to interrupt the Neutral. (A pigtail is when you connect all the wires in a Junction Box together that need spliced with a wire nut [Or equivalent], with a 6" "Pigtail" coming out to feed the receptacle. This allows you to replace said receptacle later, without interrupting power to anything downstream.)
And if you aren't using a 2-Gang Breaker, there's a chance that SOMEONE, somewhere, someday, will wire both conductors to the same phase. They might do this, even if you DO. And then the Neutral might be asked to carry 40 Amps back to the Breaker Panel, some day. It won't like that. Neither will your Homeowner's Insurance.
And here's another reason I only carry 20 Amp Spec Grade Receptacles on my truck: Replacing 15 Amp receptacles that were used as a splice for a _20 Amp circuit!!_
When one does this, one has inserted a 15 Amp fuse in the 20 Amp circuit. This alone has made me much money. _That the client should never have had to pay!_
@@1oddtech This is the way.
@@LordSaliss This is the way
What you were describing at 1:45 to run 14AWG wire on a 20A circuit but just for the lighting legs of the circuit, I believe that is against code essentially everywhere, although I'd like to be proven wrong.
If 14 gauge wire is run anywhere in the circuit the breaker must be rated at 15 amps or less. If the breaker feeding a circuit is 15 amps you can mix and match 14 gauge and 12 gauge wire all you want
NEC 240.4(D)(3) says that 14 AWG copper cannot be protected by a breaker larger than 15A
Agreed. This should be a code violation everywhere. The breaker is there to protect the wiring inside the walls, not the LED lights at the end. A 20A breaker must use 20A/12ga wire throughout the entire circuit (except short taps which have special rules). When someone later adds a couple of standard receptacles to the 14ga branch, it may overload the wire and not trip the 20A breaker.
I have asked this question before and my understanding is that his jurisdiction and some other commenters' jurisdictions interpret the switch leg to be a fixture wire and fall under article 402... Excerpt from uses permitted section: "for connecting luminaires to the branch-circuit conductors supplying the luminaires". This one is iffy in my opinion, I don't like it even though it is probably 'safe' I'd rather spend the extra few cents a foot and just stick with #12.
14 AWG = 15A OCPD
Should not be used on a 20A circuit although my whole house is wired with it lol
NEC 240.4(D)(3) - if you have any 14 AWG copper wire, the overcurrent protection cannot exceed 15A
This video is going to kill someone. :(
@@danlake7970 he makes constant mistakes in multiple videos. To the point that he takes the whole video down because he’s a moron. I wouldn’t trust anything he says in these videos. The fact that he has a business selling education material to people who don’t know better is near criminal since he is giving out false information that is deadly.
He just didn’t think this one out , he knows better. I believe his mouth just got carried away , not realizing what he was saying.
@@boby115 players f up too bro 😂
I think he's talking about 'in theory' only, which doesn't help electricians or anyone else cause we have to follow code.
If we lived in a Mad Max world where the code rules are long gone...his point is that you can put a smaller wire on branches of a circuit and it'll still be 'safe' for that small branch lol
Something seems off in the presentation. I thought the NEC forbade running cables with smaller gauge wires than the breaker’s rating for the branch. E.g., can’t use 20 amp circuit breaker to protect a 14 gage (15 amp rated) cable. Otherwise, a shorted current of say 19 amps wouldn’t trip the breaker but it would overheat the 15 amp rated cable and potentially cause a fire. Do you have the NEC reference for this?
20 years ago, all romex was white and I thought the reason it was color coded (#12 = yellow) was to allow inspectors to easily identify what is being demonstrated in this video. I do think what is being taught in this video is low risk (since LED lighting draws small amount of current), but also would like know the NEC code allowing this practice.
I believe this is the case except for certain branch circuits supplying AC motors with a starting surge.
I was always told NEVER to mix gauges of wire. For example, if I run a 12 gauge to an outlet off your light circuit, the 14 gauge wire would get hot in the wall, with the breaker never going to trip. A big no-no. I was told to protect the circuit for the lowest wire gauge and in your example. if you use #14 for your lights, the circuit breaker should be a 15a. Not 20a
Correct?
Pretty sure you are right. If there is a fault at any point on that 14 on the 20amp circuit you will get the full fault current of a 20amp circuit and the breaker will take longer to trip potentially giving Time for that fault to create other issues
That’s what I’ve always understood. The breaker protects the conductor not the device.
You are misunderstanding what is being said in the video. Dustin didn't say you can run 12awg to a receptacle from your lighting circuit, unless the entire wire from the circuit itself to the receptacle is 12awg, and the smaller gauge for lighting is only possible in some places where an inspector will allow it.
You cannot start at a 20A breaker, go 14awg up to some lights, then 12awg down to a receptacle. It must be:
20A breaker to a receptacle with 12awg, from the receptacle to a switch at 12awg, from the switch to the light at 14awg. That 14 cannot go to anything else and must only go to the lights themselves and only after the switch.
A short in the 14awg area will perform about the same as a short in the 12awg area. Both of them would draw more than 20A, and both shorts would trip the breaker. The 14awg is also still oversized to the current LED loads, but is sized correctly to the load if someone were to switch to incandescent again (though those aren't even sold any longer so you can't really do that). Per the current NEC 240.5(B)(2), you are allowed to do this for light fixture lighting.
@@LordSaliss I think you might be misunderstanding the function of an OCPD. It is a safety device. In the event of a fault where more current flows than the #14 is rated for the 20A breaker won’t protect it.
It being a lightning portion of the circuit is irrelevant since the breaker is there to protect from abnormal operating conditions. (Fault)
@@LordSaliss I agree, however I have been told the circuit has #14 anywhere, the entire circuit must be protected by a 15A breaker even if you have a #12 leaving the box.
I own a duplex where they basically did this on some of the receptacles. 20A breaker with some 14awg feeding the last few receptacles. Tenant had his gaming PC setup (multiple monitors, high power pc stuff etc) and nearby baseboard heat going. The 14awg was probably drawing over the 12 amps it really ever should have been drawing. With the combination of the heat from the pc and baseboard and the overloaded wire, it melted off the receptacle. Luckily didn’t start a fire but that’s how I found out about it. I imagine a 15 amp breaker may have prevented the problem which is what I put on instead.
Moral of the story, DONT MIX AND MATCH WIRE!!!
IN THEORY that is correct… the switch leg will never carry the load the home run will carry. BUT, I’m pretty sure that code wise, the conductor size must match the rating of the breaker ampacity ALL THROUGHOUT THE CIRCUIT… meaning a #14 AWG switch leg on a 20 amp circuit still violates code.
I think the new standard method of new construction home wiring is to run 15 amp circuits for lighting & smoke detectors because 14/2 & 14/3 is so much cheaper… especially for travelers & smoke detector interconnect… than 12/2 & 12/3, and LEDs are so efficient anyways. LEDs just don’t require much current like old incandescent bulbs.
For circuits supplying receptacles & other power, electricians use #12 AWG/20 amp circuits in new construction to accommodate appliances that draw more current. A vacuum might draw 7 amps & a space heater might draw 12 so #14 AWG/15 amp circuits can be inadequate for powering receptacles.
I still don’t think that #14 AWG switch leg on a 20 amp circuit would would pass with our inspectors even if in theory what you’re saying is totally correct. There are many portions of that circuit that will not carry the full load.
Yes, by adding the 14ga anywhere you must reduce the breaker to 15amps which would reduce the total allowable load rating of all the receptacle in the circuit from his example and totally negate any possible wire cost savings, which IMO is not even a good reason as long term over the life of the service those savings are negligible pennies a day for a better gauge wire. This video was good in theory but not in practice.
Woah. But if the homeowner goes screwing in a bunch of old incandescent bulbs, or one of those screw-in adapters that turns a light socket into a receptacle, or a cheap light fails in a weird way that draws too much power but isn't a dead short, then it's entirely possible to overload that 14AWG wire if it's on a 20A breaker. Is the breaker meant to protect the wiring or isn't it?
My quite non-professional interpretation: If you're connecting can lights with sockets, that's a consideration; but the new LED luminaires don't have sockets for the lamps, so there's no way to connect an incandescent lamp to them. As for Dustin's comment that you could theoretically use tiny wire because the LEDs draw so little current, I was wondering about electrical fault danger, too. Seems like that wire could get dangerously hot, and provide enough resistance as to not draw the full trip amperage of the breaker. Would love to know if this is a legitimate concern.
@@soundman1402 I thought about this a lot (have not gone to the code book yet) but how about this.....Regardless of 12 or 14 awg going to the LED fixture, (or even incandescent for that matter), the fixture itself is internally wired with 18awg so this is the lightest gauge wire on either a 20A or 15A breaker.
@@sdsconstruction Sure, but you can replace the fixture without cutting up all the drywall.
First of all, if you have 14AWG anywhere in the branch circuit, the maximum breaker size is 15A. Even still, a lamp holder like you're describing isn't a luminaire per the code, so you can't rely on a particular low-power bulb being installed in it to reduce the load calculations. You'd have to assume that someone might install the most powerful possible bulb and plan accordingly.
Ya, just like Dustin said you could use something crazy small, like coax or audio cable, he does close with using code or better.
He's a decent advocate for minding/reducing voltage drop as well, which is generally only obtainable by 'oversizing' cable on the best new branch circuits.
It's the same thing for us down here in the Caribbean. We use 14/2 for the light leg & 12/2 for everything coming out of the main breaker panel
I hope those 15 Amp rated cables are only being connected to a circuit with a 15 Amp breaker.
He said the 14 gauge is going to lights. Why would that be a problem?@@TimeSurfer206
First and foremost I want to thank you for taking your time to post these videos. I appreciate them deeper than you know.
I'm one of those "ADHD" guys and I went to the electrician's apprenticeship at 37 years old. I learn best by hands on. And the apprenticeship I went through was well over 90% book work or computer. I went through it in the middle of the pandemic too so a lot of stuff was on zoom as well. Completely horrible for an ADHD brain like mine.
I learn best by physically doing the work and then going back and seeing how it works because that makes it more interesting for my brain.
I passed my apprenticeship a little above average but not by much and half of that was because I found the answers to a lot of my homework so I didn't end up doing a lot of it. Which also didn't help retaining any kind of knowledge.
But now that I've been in the field working, I'm going back and watching these videos. It's like the puzzle pieces of my brain are finally falling into place. I'm a solid electrician when it comes to my work. It's always clean and it is always correct.
But to have the understanding behind everything allows my troubleshooting skills to get that much better and to explain things a little bit better to the people around me when I'm doing my work.
So again thank you for these posts.
You sound a lot like the way I understand things. So If my home has existing 12-2, can I connect 14-2 for a bathroom light, bathroom fan and, one out let?
Great explanation.
After working with cheap #18 luminary wire behind a fixture that breaks, I'd rather stick with something larger.
Plus, if they repurpose the circuit for a vent fan or warming light they will need the current.
Never cheat code, always go above the minimum.
I teach HAM radio licensing classes and the parallel / series differences in voltage and amperage is one of the hardest things for students to wrap their heads around.
Excellent use of visual aids to show how it works.
Wire is sized for the breaker it's on, regardless of the load that may be on it.
If the 14 AWG romex somehow gets cut on a can light housing or the LED fixture goes bad, and that draws a heavy load without shorting, the wire will get too hot before a 20A breaker trips at 27+ amps.
This is exactly why I watched this video, we have new code inspectors, that I don't trust their knowledge, since they don't seem to have any experience at all. So now I need to figure out of I'm going to run a home run of 14/2 for all the lights and fans, or run 12/3 to 20 lights and two ceiling fans. From what I got out of his video that is fine, but I was still 2nd guessing the idea. Normally I run 12/2 for all 120v runs, since I have a bunch of rentals, and you never know when the tenants are going to try and heat the whole hose with space heaters. But this is for my house, and hate to waste that much 12/2 and 12/3 for a bunch of LED lights.
IMO this video needs taken down, because from what I got out of the video it is fine to run a 20 amp breaker, then 12/2 to the outlets, then branch 14/2 off that.. but NEC 240.4(D)(3) says different.
Well time to see how many spots I have left on the breaker panel.. that sucker is starting to run short, and not running them silly mini doubles.
And yet most outlets are rated at 15amps on a 20 amps service, but I guess they'd melt in the box.?
@maxjankowski6892 15a outlets are the same internally as 20s, minus the extra tab for a 20a plug, so daisy chaining 15s on 12awg wire on a 20a breaker is okay.
It could get a melty neutral slot if someone managed to draw near 20a through one of the duplex outlets. I've seen that with an old window air conditioner that was running very inefficiently, and a space heater connected to a short appliance extention cord causing extra resistance.
I hate trimming in #12!
Great video as always! You mentioned LED on Ethernet cable; I received approval from my inspector to run all LED lights throughout the house, to be connected to a “separate” 12v powered panel with Ethernet cable. My wife and I are renovating a 1910 Farmhouse, excited to see this project through.
I completely disagree. If you have a 20 amps breaker, code does not allow you to reduce conductor size based on actual load except in very very specific situations. The idea being that if you have an overload (say a high impedance short circuit) in the circuit and you have reduced the conductor, it may melt before the cb trips. By sizing all conductors according to upstream protection you prevent this situation from happening
I agree the Breaker is to protect the wire! or the equipment!
Yeah that was my immediate thought; what clears the fault on the LED leg before the wire melts? In principal it'd be safe if that leg had an additional fuse or something but IDK if there's even code for that.
Plus once you start mixing different gauge wires and splicing things together it all becomes a mess to deal with for any future person making repairs or modifications.
I changed my position on this.
I am not worried about a sharp short-circuit condition that would cause 100s or even 1000s of amps to flow in the circuit. A 20A cb magnetic protection would trip instantenously and clear the fault and limit the total energy (Amps x Time) below the allowable thermal envelope of both 12AWG and 14AWG wires.
I am worried about overloads or high impedence faults, which would limit the fault current to lower levels (between 15 and 20ish Amps), which takes the cb much much longer to clear and could generate too much energy and melt a 14AWG wire.
Now, are there jurisdictions that consider the situation of such a fault happening unlikely enough for lighting legs that they build exceptions into local codes for reducing conductor size to 14AWG on a 20A breaker? Yes, I believe that is likely. I would still prefer feeing the lighting circuit from a 15A breaker though.
@@philibertperusse8998 What about a fault condition that doesn't draw 100's of amps, but somewhere between 15 and 20? And is not detected for years, could that cause overheating in the 14-gauge wire and eventual breakdown of the insulation?
I worked
with a maintenance guy who installed 12 to every outlet every time. 🤔 His theory was surprisingly rational. The buildings were built in the 1960s and there weren’t even remotely enough electrical outlets. As such he expected that any outlet he installed would have multiple extension cords and port multipliers added and so the circuit should naturally be capable of supporting the expected load.
By me, the only time 12 gets used on a 15A circuit is on really long homeruns to guard against voltage drop. And I never use 14 on a 20A circuit. We use 12 gauge(20A), for kitchen receptacles, bath receptacles, laundry receptacles, dining receptacles, and garage receptacles. Everything else gets 14 gauge(15A).
I agree the Breaker is to protect the wire!
The cost difference when considering the better wire over the life of the system translates to pennies for a much better product long term. Same goes with using the higher quality 20amp receptacle outlets over the cheap homeowner grade 15amp outlets.
Got a question for you, if you can give me a sneer that’s be cool!
If you are installing a receptacle to a small commercial tv store should you be using 14 AWG or 12 AWG? Is there any specific code for it or do you follow the amps the receptacle you’re adding needs? (For example if I’m adding a 15 amp recep I use 14AWG because that’s rated for the 15A)?
@@ADA_thesparky You aren't allow to used 14 AWG in Commercial places
Someone who knows what they are doing. 12 wire dummies!!
In Canada, 14 gauge (15 amps) is commonly used for majority of homes outlet and lighting circuits, usually combind for individual rooms. 12 gauge(20 amps) is required for kitchens/dinning rooms, bathrooms, utility rooms and garages.
Yeah, I didn't even tought this had to be mentionned honestly... It's common sens. Isn't this channel for electricians only?
That's how we wire.
I have lived in Alabama my whole life. I purchase a newly built home in 2008. The wiring in that home was exactly as you described in Canada. I recently moved, buying a home built in 1985. I have seen some really janky wiring. Bedrooms have 15A and 14/2 Romex. But lighting and outlets are all on the same circuits. Additionally, they put the furnace/air handler on the same circuit as some outlets in the Main BR and the bathroom lighting. Plus, half the kitchen is on the same circuit as the dining room, basement stairwell and garage. Half the living room is on the same circuit as the basement lighting (separate from garage lighting), while the other half is on the same circuit is on the same circuit as the outside floods and the garage outlets (also separate from the garage lighting). Still, as janky as all that is, it isn't as janky as the house I grew up in, which was built in 1954. Let's just say that when I saw how the house was wired, I thank God each day that we all didn't die in a house fire growing up.
There are some areas in canada that uses 12 instead of 14 because of how hot they are in the summer. Can’t remember exactly where
@@DGTubbs Lol. Well don’t go into any houses built before world war ll. You will probably run down the street screaming. Houses are built to the code of that Era. The Code across the country is on a 3 year change cycle. So I’m sure your 2008 home is not in compliance with current code. Neither is my Custom built home from 1980. Nothing to worry about. Just maintain it and don’t do any thing Janky. Lol.
WOW to you! I'm learning about running wire in my bathroom for an additional light which has 3 LED lights. You are the only one video I've watched that really explained things to me in the way I understand. Thanks for sharing
This answered a couple questions that have been nagging me for a while now -- hugely appreciated, thank you! :)
The only thing I see wrong here is if you put 14/2 onto a circuit that has a 12/2 home run and is fed by a 20-amp breaker, you’re actually not in compliance because all the cabling that comes off a 20-amp breaker needs to be rated for 20 amps.
Good point. confusion.
Is it legal to put a breaker at the lower powered branch itself? Or a fuse?
I have asked this question before and my understanding is that his jurisdiction and some other commenters' jurisdictions interpret the switch leg to be a fixture wire and fall under article 402... Excerpt from uses permitted section: "for connecting luminaires to the branch-circuit conductors supplying the luminaires". This one is iffy in my opinion, I don't like it even though it is probably 'safe' I'd rather spend the extra few cents a foot and just stick with #12.
LED lighting is a pain in ass to connect with larger than 14awg. The connection box is so small.. and i dont know why.
So, for lighting, use 15A breakers. And outlets, use 12/2 just in case you decide to change your 15A outlets to 15-20A outlets.
Except working w 12 sucks wiener compared to 14. Pretty sure it falls under the fixture wires code section (I think someone else said 402). Just run lighting on a 15 amp breaker and then you’re safe.
My new home (2 years old) in Georgia used all 15 amp AFCI breakers and 14 gauge wire on all lighting and receptical circuits (except for dedicated, 20A recepticals like microwave, cloths washer, etc.).
Yup, pretty standard mass produced home issue. The contractors do the minimum required because they don't have to live with the results.
Interesting debate watching from the sidelines of non-trade but activtly intereted community.
Looking forward to seeing where this ends up.
99/100 dustin gives us top notch content. And who knows what oddities are in different codes. Right or wrong, looking forward to being educated!
I don't think this is what you intended, but this video comes across as claiming you can run 14ga on a 20a breaker depending on the intended load. Which would be really bad if the intended load changed to something not intended. You should clarify.
He does clarify, when he states the codes, to use as dictated in code, and showed the charts of required cable size to circuit (breaker) amperage.
Great explanation. I live in an old house. Some circuits have been upgraded to 12/2, while some receptacles are still K&T, unfortunately. I'm trying to add a receptacle in Kitchen, inside cabinet, powers only the electronics for stove/range and the exhaust fan/hood lighting. I was going to use 14/2 for the additional receptscle, but the one I'm tying into is 12/2. I've decided to go 12/2, to match existing conditions. One thing I see is that the existing 12/2 Romex has Green insulation/jacket of Ground wire. I cannot seem to find 12/2 Romex wirh Green insulation/jacket on ground wire, only bare ground wire... Have they stopped coating Romex ground wire with green jackets now?
My mind is blown. I thought you can’t run wires rated below the OCPD. If something goes wrong (even though it’s not going to happen) and those lights draw 16 amps, that 1AWG is going to heat up. Have I been wrong this whole time? I can maybe see what you’re saying if it was a low voltage system with a transformer involved. Otherwise I’m going to be looking into this for the next 6 months trying to convince myself it’s ok lol.
You're correct. I just spent over an hour reading the NEC researching this, and basically: 20A circuit = #12 wire or larger only. #14 wire = 15A breaker only. There are some exceptions, but none of them apply to running Romex to light fixtures. Fixture wires and tap conductors that run no more than 18" from a junction box to the fixture can be #14 or smaller, but anything beyond that has to be sized to the breaker.
As an electrical engineer, It's not the way I would ever design a circuit released into the wild. Although you might get away with it without killing anyone if you have an AFCI breaker on the line.
Thanks for clarifying. I could still see using it on cabinet lighting that was 12 volts but I wouldn’t want that on a 20A breaker either. Would AFCI possibly save you from killing someone because it should trip before a condition is met that would cause it to draw more than 15 amps? Because I’m thinking if for some reason it draws 16 amps without an arc the 20A AFCI is going to let the wire heat up. Obviously this is becoming academic now.
@@doc13067 And you would be correct. The "electrical engineer" you responded to proves the case that most engineers don't know jack about what they are talking about. The AFCI protects against ARC FAULTS, NOT OVERCURRENT which is the main issue. The ONLY way an AFCI would be of benefit is IF the overcurrent finally melted the wire enough to start an arc fault, which the AFCI MIGHT clear. But by that point, enough heat would have been generated to start a fire.
Mr. Engineer needs to learn how the real world works, and crack open a Code Book AND learn about Ohm's Law and current ampacities of materials.
Man, I don’t know if it’s how you explain it but it makes so much sense. I appreciate the content and the time you take to explain it visuals, it jumps makes it easier to understand. Keep the great content coming. I find super informative.
It’s funny, cuz in places like the UK, they do undersize the wire, and add an additional overcurrent protection on the smaller wire branch. That’s also why their plugs are so big, they have to have fuses in them so they don’t overload the building wire.
There is low voltage lighting systems with smaller wiring, and even lighting that runs off of power over Ethernet now. Seems like we should start having mini “sub panels” where we run 12 2 to a room, then have a “mini panel” with 1 amp breakers and smaller wiring for “low amp” lighting circuits.
Bro I know all this. Learned it quite some time ago. I can’t tell you how invaluable these videos are. New info, new insight, refreshers, different methods. It’s all great stuff and I encourage you to keep it coming!
Greatest YT Electrician Instructor ever. I challenge you to find a better RUclips electrician channel. I wish I could subscribe 100 times.
If i understood correctly you used 12 gauge on everything before the LED lights and ran a 14 gauge leg for the LED and that 2nd receptacle.. so without that 16 amp load you essentially said use the correct load for your breaker?
Glad to see a lot of concern in the comments, reinforces my confusion watching the video. I am not an electrician but I've done a little research for DIY purposes. My understanding: 12-gauge wire needs 20-amp breaker protection, 14-gauge wire needs 15-amp breaker protection. Running 14-gauge wire anywhere in a circuit that is connected to a 20-amp breaker is a no-no because 14-gauge wire is only rated for 15 amps, so if there is some sort of fault condition in the circuit that draws more than 15 amps but less than 20 amps you could have a potential fire hazard.
14 gauge wire needs a 15A breaker.
In Seattle inspectors will allow you to wire the house with 12 2 and 14 2 but not a mixed circuit, either all 12 awg or 14. Awg.
Makes sense that you could run #14 off a switch leg. Also it's easier to identify the light wires at a glance vs having to test for your hot feed.
I think they recommend 12-2 all round is to simplify safety verification. No chance of an overheat due to resistance. Though like you said, smaller would carry the load. I mean most fixtures only have like 18 or 20 gauge strand or solid in them. So that's automatic resistance right there. But, it's contained. Where your lines run tacked to wooden studs and joists. Potential heat absorbers. And, if someone gets heavy on the hammer with a staple, it could be a potential fire later.
My daughter had an outlet with a toaster plugged into it that kept tripping the breaker. I pulled the box, checked the wiring, the outlet, found nothing. Went to the panel and looking, spotted nothing. But when I pulled the breaker, whomever stripped the wire at the breaker cut almost all the way through the wire. So when the toaster ran for several minutes the wire got so hot it kicked the breaker. So, in the famous words of the Borg, resistance is futile .
i know a electrician who always crushed the wires in a panel. told him to quit doing that. bad work like that. will lead to problems. like yours.
14 is allowed here in Oregon, and is actually used more here for lighting circuits. Most lighting nowadays is LED and the load is less than it ever has been. There is even a provision in the new NEC for a new 10 amp breaker. Wether or not Manufacturers pick this up, is yet to be seen. If you are running a mile or more of wire, 14 can be quite a cost savings. Thanks, Russ 28 years in the Trade.
Back in the days of incandescent lights and plug in the vacuum cleaners, bigger wires meant brighter lights and stronger vacuums. With LEDs and cordless electric, the demands on those circuits are much lower. Still remember to oversize the car charger, dryer, and range circuits. Reducing the voltage drop will save the customer thousands of dollars over the life of the home.
Ding ding ding! This is why I use 12 gauge for lighting. Many electricians like to overlook how convoluted and LONG a lighting run can get.
I totally see what you’re saying. But those cordless battery powered vacs will never compare to a plug in the wall vac. I have one of those cordless vacs and, to get the same suction as it’s corded counterpart from the same brand, I have to put it on “boost” mode. That gives me maybe 10-15 minutes of vac time before the battery is completely depleted. Who wants to vac for 10 mins and then charge for 4 hours to get another 10min of vac time? It’s like electric vehicles. Waste of time.
The vast majority of people still use a plug-in vacuum cleaner.
@@miket5506 Guess it just depends on how much floor you have. 🤷♂
I have a lawn service. 5 years ago I would not have even entertained the idea of cordless electric OPT. Now all my equipment is battery electric. It was just a matter of solving the refueling problem.
Having said that, I agree, there are some battery powered tools out there that only belong in the discount stores where cheep people buy cheep merch.
@@miket5506 Never? Technology advances. I give it 5-10 years before most battery powered tools will surpass the performance of plug in varieties.
The drain pump on my Whirlpool washing machine is fed by 21AWG from the factory with a factory vampire wire piercing connection for termination. The bean-counters probably got a nice Christmas Bonus for sizing the wire "just right". The vampire connection caused the wire to corrode and fall off the pump. That's how I found this ingenious bit of engineering.
I have 19AWG on a Kenmore vacuum, manufactured by Panasonic. You normally only see even-numbered sizes.
Some of my RC car speed controllers have 13AWG. Seems strange since most batteries for them come with 12AWG or thicker.
I like this how it shows parallel bs series and such. What’s even better to teach people to understand it is make them wire single then eventually dual voice coil speakers that are different ohm and amps that can handle a wide load of ohms but of course deliver there max at there lowest possible ohms. It really gives you an understanding even tho it’s DC
Just learned more about parallel circuits in 8 minutes than I did the entire month we spent on dc theory in my union dc theory course. But my instructor was also more obsessed with his 20% fail quota he was trying to reach…. The way he teaches it’s no wonder 20% of his students fail first year.
Please disregard this video. I am not sure what he was thinking, but this is wrong. Read the number of comments.
It's good stuff, but do note the breaker is the safety for every device AND the cable of the circuit, so actually do use the cable coded. While yes, a shorter run of 14awg will perform just as well as a longer run of 12awg at 20a, and be safer, it's still codified as a no-go.
Use this info to help reduce voltage drop! Meaning, to upsize certain runs, like the home runs with devices on pigtailed smaller awg 'twig' circuits. The professional who just wants to use the minimum required, do the minimum, just pass inspection; worries far less about the circuit's use and voltage drop, and more about the few dollars saved.
One of the differences between Canada and the US is use of 12/2. For residential homes almost all circuits are 14/2, 15A circuits. Those 20A circuits that you guys use are rare here, at least in homes built ten years ago. I find that particularly irritating in my garages over the years. Some power tools like my table saw are right at the limit of 15 A circuits, and old homes share lighting with power outlets. Add in the voltage drop from panel to garage, and the table saw needs to spike current higher (and longer) to spool up. That's a recipe for a blown circuit breaker.
Question: getting ready to wire a shop - Better to use Romex or single wires? Your opinion?
I did not see a mention on conductor volume in recessed cans JB. Lots are only rated for 2 14/2 cables, not 2. 12/2 cables.
There is only one question. Is the breaker going to trip before the wire in your wall heats up and starts a fire? Technically you can have 1 amp circuit on 14/2, but if you put that on a 20 amp breaker, and anything goes wrong with your LEDs, your breaker may not trip before you have a real problem.
Correct. Though probably not with a dual function breaker. Should cover that 'something.'
But that's why Dustin says use code, says the common minimums, and shows the NEX table for cable size vs circuit protection size.
Question on parallel ckt example where it is mentioned branch circuits could use smaller size wire if loads are small.
How would the smaller wires sized ckts be protected from a SHORT condition in the branch?
I would think 20A would be sourced from the main panel and burn the wires that could not handle the current.
In my company, if we are doing a remodel or service call and find 14awg wiring on a 20 amp breaker, we will ALWAYS downsize the breaker to a 15 amp one or upsize the wire. You never know what may have changed in an older home.
You do so because that what the Electrical Code says to do.
I believe the code should be lighting =14/2 or (12/2 optional) and all plug receptacles 12/2 regardless… just my opinion. I see too many people for all the items they plug in these days overloading more 14/2 receptacles than 12/2 receptacles… nice video as always dustin…👍👍👍
If I was to reinvent the wheel tomorrow, I'd want homeruns to run in attics or basements, with essentially pigtailed 'twig' circuits down/up to devices. The homeruns would be oversized, to 10awg for circuits with receptacles, though pigtailed out to receptacles with 12awg. Less in walls, more access, safer with receptacles pigtailed, and easier to modify like adding new receptacles/other devices.
Even if planning on LED, if installing an E26 socket device requires we use Maximum of the rating in box. We still have to use 12 on lights because of this.
Think he was talking the directly wired LED fixtures. It would feel ridiculous to be running 12awg just to get to each light and use their cheap push-connect fittings to splice to tiny ~20awg wire and to draw ~10w. Code is bureaucracy, and the actual goal of any bureaucracy is survival, not their propaganda message as to what their mission is. It's rarely very efficient, usually adds needless cost, and long term makes what they control overall worse and eventually unaffordable.
I ran my entire home in 12/2, it's weird, lots of people said "Good call", still lots of people said "You know you could have used 14/2 for the lights right?". Since it's my home, I like being able to turn off entire rooms. Voltage drop was a big concern for me, as I have a 130' home, and even though the breaker boxes are centralized, some homeruns were around 100' long in places.
So, I ran a voltage drop calculation using 14 gauge wire, I had to assume a couple of things of course because I do not know your house layout. Assuming, you have a 100' run, with 30 75-watt equivalent LEDs (13W actual power draw), you would draw roughly 3.3 amps. Ran through a simple voltage drop calculation, you would only lose ~2 Volts which is a 1.6% loss, which is negligible and would not affect the circuit much at all, if I remember correctly you want to be +/- 5% and I put a lot of lights on that particular circuit, generally, lighting layouts are divided up more. In general, with certain exceptions, voltage drop in residential homes is negligible and rarely comes up. It's not unheard of, but usually it doesn't affect the run. Nothing wrong with what you did, just food for thought.
@@TheRiddler491 Thanks for that, I know it doesn't usually come up, however my rental house before that had bad voltage drop on one end of the home. It annoyed me, and others greatly! I wanted to do whatever I could to prevent it. Also, my actual circuit could be longer than 100', once you account for the rest of the circuit. Strangely enough, after all that, my led lights fluctuate in brightness when my washer is swishing around the water. I think that is more bum led lights.
The cost difference is not much when you consider the 30+ years of service. I ran 12/2 for everything in my house as well. Same with the receptacles, commercial grade 20 amp outlets. Again the cost difference over the life of the product makes it a no brainer.
@@raterus Interesting, did you wire your house? I find it odd that they would fluctuate after the unit is running. Could be shit LED's but I assume they are not on the same circuit. You see it a lot in older homes where your turn on the microwave and the lights dim because they are on the same circuit. As far as your old apartment, they probably tied a bunch of things together which could cause lights to dim. If you have a bunch of things on one circuit, this could also cause voltage to drop as it is electrical pressure much like turning on all the water sources in your home. The demand exceeds supply, causing voltage loss. Voltage loss only really happens in extreme distances and is considered for such things as parking lot lights and such. There are many factors to consider here aside from distance.
Not just "good call", the 12AWG wire is necessary at that length to meet voltage drop rules
In some California apartment buildings 3 decades ago the only place where 14 awg was allowed was the sole circuit to the smoke alarm..
All else was 12 awg since you assumed the tenants would do crazy stuff. Lol. Liability
The breaker for the 1.5 ton ac compressor on the roof was 10awg for most apartments..
I’m ready to overcome my fear of installing two 20 amp circuits for my garage. Currently it’s on 15 amp for interior and exterior lights and outlets with 12/2, 12/3, 10/2 and 14/2 Romex including for two 3 way switches in a double gang box. There’s no way an electrician wired this unless they were visually blind.
I purchased 12/3 & 12/2 Romax. Do I wire the circuits with the 12/3 or 12/2. Where does the red wire go in the panel. I’ve seen videos only explaining the ground, white and hot black wire.
Personally, if I was building a house right now, I'd go with 12/2 everywhere, just because you don't know how you're going to use the house in the future. A little extra headroom feels like a good idea. I'd bet that upgrading even just one branch at a later date is going to cost more than the difference of using 12/2 versus 14/2. 12/2 is harder to work with, though.
Their forcing everything to be electric so it’s better to have it and not need it than need it and not have it.
I totally agree I never use 14 /2 for anything I don’t care if it costs a little less
It’s actually surprising how quickly you can run into box fill issues with #12 in residential boxes.
You plan on welding in your living room ? other than electric range or water heater, there's no reason for #12 in a home
@@ericschulze5641 In my case, we have a home office with four relatively high-end computers, a laser printer, and a 3D printer all on one circuit. Add a space heater and it's pushing tripping the breaker.
It's always so much pleasurable to work with the 14 gauge vs the 12 when you do.
Especially when it's a Rental, and they're using Space Heaters. Melted receptacles are Job Security.
@@TimeSurfer206 it won't melt if it's on a 15 amp with 14 wire.
I knew a guy whose father cut sheet metal with tin snips for US Steel his whole career. I also served in the Reserve with a guy whose civilian job was as a commercial electrician, who only ever worked with 12 AWG wire. I shook each man's hand once. After that, they only got knuckle bumps from me.
@@vaska916 I just got back from a job yesterday with two pieces of scrap that prove you're wrong.
They were 15A, El Cheapo Contractor Specials, on 12 gauge with a 15A breaker.
They were replaced with Spec Grade 20A's.
It's a Rental. The cheaper you go in a Rental, _the quicker it's going to break._
This video could've been 2 minutes long. As long as you're installing a 15A breaker (and your AHJ allows 15A circuits), then yes you can use #14 wire, because #14 copper can handle 15A (240.4(D)(4)). If you're running a 20A circuit, then you MUST use #12 (or larger) wire. There are exceptions, but none of them apply to running Romex to light fixtures. EVERY section of wire must be at least #12, even if it's just feeding a single light fixture.
He seems to disagree with you.
@@phi5head And I disagree with him. I read all of the code sections he mentioned in the video, and nothing in any of those sections says that you can run #14 to light fixtures on a 20A circuit. I'm more than willing to admit I'm wrong if someone points out a code section that says otherwise.
@@jonclark1288 I'm with you. It will be interesting to see if he addresses all of the people in the comments telling him he's wrong to be doing that.
Ahj was the key words here
@@jonclark1288 It doesn't make sense to me. i can understand if it's a 15A breaker. #12 to the outlets to prevent voltage drop, and #14 to lights since under normal loads they draw very little power. But even then, I rather have #12 go to the lights since I've had issues with LEDs flickering when the voltage drops slightly. Also don't have to worry about how much of what # wire you have, just buy #12 and forget about it.
hello,can i use 12/2 romex on recess/pot lights?
Maybe 40 years ago in my area you were allowed to run 14/2 from a wall case that had a switch to control ceiling lights that were feed off a 12 guage 20 amp circuit breaker but no longer.
I had a situation where someone plugged in a 16 gauge device that had shorted leads, only the circuit breaker was a 30 amp breaker. The circuit breaker didn't trip, but the 16 gauge wire disintegrated at the plug. This is the main reason why I only run 14 gauge wire and use 15 amp breakers for lighting. If something goes wrong with the lighting on small gauge wire or a lamp failure, there is a better chance of the breaker tripping with the wire being only one size smaller. By the way, the only way I could fix the 30 amp receptacles problem was to use a spare hot on a different leg that was already in the same conduit but had to share the neutral and use a two pole 20 amp breaker. Both circuits remained contained in the same Wiremold Plugmold power strip that provided odd receptacles on one leg and the even receptacles on the other.
While fixture whips can be undersized there is no provision allowing what you described. You can't just refer generally to three different sections none of which say what you want. NM is not a "fixture wire."
Thanks for talking about this. I was even thinking of requesting it a few months ago. I've been really appreciating the design of circuits lately. Not getting crazy, but definitely reducing voltage drop as much as practical. Even doing 10/2 main runs with 12/2 or 14/2 off of them when practical.
I'll need to read more in to when I'm still allowed to use 14/2 on 20a circuits if for specific devices. Was under impression that 20a means 14/2 is vorbotten, but maybe not. Will look. And will look for 240v as well, as a lot of the 240v I've done really did have low amp devices with short, harder to run, final circuits from main run.
You can never go down in wire size....ever. If it's a 20 amp breaker, you have to stay 12 gauge the entire circuit.
@@imtheonevanhalen1557 A device's wiring can be less. On dedicated 'hard' wiring, there's argument to be made for where that wiring begins, best I've heard. Reason, the wiring in most devices is significantly smaller. I feel a little disappointed and defeated when I oversize the conductors for a circuit only to be slicing to something like 16ga. But I know it's because those wires are short enough to be fine. Most power cords are also 14ga or much smaller. But it's also a lot easier to splice some 14ga to fish up through a floor to a baseboard heater than has 16ga wire inside it to splice to. Also, 240v. Lol
You didn't mention it, but I'm assuming you also account for the cable length in your total draw calculation?
What a great video, you made a difference in how I would rewire my house, thanks 🙏🏼
you can also run cat-6 for led lighting. PoE service, your stitches are in the software.
Here is a DIY question for ya......How can you tell what gauge the wire is if it is not part of the original package with description. I have some old wire in my garage. I know it is electrical wire and not CAT5 patch or anything like that. The wire looks white shielded just like in this video but the wire does not have any markings on the shielding that I can discern. Thoughts?
If the conductor is the size of a dime's edge, it's 14 AWG. If the conductor is the size of a nickel's edge, it's 12 AWG.
I'm running a outlet to my crawlspace a 15 amp GFCI outlet from a kitchen outlet that never gets used . What size wire should I run the outlet with ? Any help would be appreciated.! The outlet is to run a dehumidifier and a condensation pump and 60 cfm exhaust fan .
Always use 12/2 when wiring lights and receptacles because it's like having extra insurance but of course just 20 amp
This fails to account for a wiring fault (such as critters chewing the insulation) or an overload situation that could cause 14ga to get too hot and start a fire. You can’t put 14ga on a 20a breaker no matter how you want to spin it!
But he said that and showed the chart.
I really appreciate the electrical diagram explaining current flow. Thx
This is an unrelated question but is it ok to use 12 ga THWN stranded wire in underground pvc conduit, or do I need to use a direct bury rated flat 12/2 w/g cable?
I have a light on the wall of a small room that has a 14/2 wire, my question is if I can draw electricity to put an outlet on that line of light? Or is it dangerous to connect a 12/2 wire to a 14/2 light?
The only way I can see getting into trouble with the whiteboard drawing, is if there is a short in the lighting circuit. Now you have a failure event and the breaker is not sensitive enough to protect it.
Of course it will trip for a dead short. Will it trip for a lesser but still very dangerous failure?
I wonder if this is assuming dual function breakers since they are becoming so prevalent? That ought to detect and trip for most faults.
That was my immediate thought as well. I'd be nervous of somehow overloading the 14ga on a 20amp breaker and causing a fire.
I've had this question about extension cords. I'm using my dad's old extension cord and it's from the 80s and I didn't see any markings on it. I have no idea what size it is. I ended up buying a 25' 12/3 simply because they said it could handle 20 amps and it has 3 plugs on it. Doubt I'll ever use that much but I feel better knowing I've got a good one now.
Ok, non-electrical question: what type of board are you drawing on. Would be GREAT to use when I’m helping my kids with algebra homework.
Nice and simply communicated info - thanks for your expertise and awesome communication skills/methods !!
When i recently rewired my house i ran 12/2 on 20amp breakers for power and 14/2 on 15amp breakers for lights. Two breakers for each room.
Everything was inspected without issues.
homeowner here, probably going further into the rabbit hole than i need to (just want to replace an outlet in bedroom), but you could, theoretically, use 12/2 whenever you could use 14/2, right? just not vice versa?
Correct
I'm retired and shocked over high price of copper wire. Think the first 250' box of 12/2 NM cable that I purchased was only $12. Always ran 12/2 to each bedroom but still think the NEC should follow you to run 14/2 to luminaries especially since they are now LED'S consuming less then 1 amp. Heard they want 14/2 copper clad aluminum cable be installed to tree luminares and be in a maximum of a 10 amp circuit breaker.
On a circuit with a dual function breaker, yep; but otherwise the breaker has to be sized to protect everything when things go wrong, including the cable, so it's more about sizing the breaker/fuse protection to the circuit cable and devices rather than the other way around (like we normally think of it).
Aluminum wire shouldn’t be used in any circuit with switches or plugs.
What happens when you get a short in one of those 14-gauge light circuits on the 20 Amp breaker? Possibility of 14-gauge wiring melting / fire before the breaker reacts?
Wow, that was confusing and conflicting information about circuitry and ampacity. You have to use correct overcurrent protection for the smallest size wire on a branch circuit, so combining 12cu and 14cu is not recommended or legal. Unless your loads on the 14gauge wire is on the load side of a low voltage driver and/or transformer
I only use 12 on bath dedicated, kitchen, laundry recep and garage recep.
I kept all lighting circuits separate from receptacle circuit when I wired my house. 15a breakers and 14ga wire. Every single light inside and outside my home adds up to like 2 amps.
Love the active board. Thanks again for the work.
Of course with the vast # of exemptions you are allowed to have a 14 guage line feeding a dedicated motor load such as a air compressor or air conditioner on a 20 amp circuit breaker to prevent a 15 amp breaker from tripping due to locked rotor current during start up. Same with a #12 guage wire can be feed from a 25 or 30 amp breaker. If you had a mansion with a fire pump breaker would be very high.
I will never use 12/2 Romex for lighting in any type of residential application.
I really can care less what the authority having jurisdiction aka the inspector has to say about it. Because the inspectors job is to make sure we did our job up to the NEC.
Inspector is not there to make up his own rules which many of them tried to do.
My house was built in 1983. Second owner. All wiring to the breaker panel is 12/3 (or bigger for 220v circuits). There is *NO 14/3 ga* wire anywhere in the house. *Does that mean* if i want to install 6 LED wafer lights and tie in to an existing 12 ga wire that I *CAN NOT* use 14 ga...
@Electrician U If i am running a bedroom can i put the lights (LED) on 14/2 & also add my receptacles with 12/2 as long as I run 12/2 straight to the panel??
I run lighting circuits on 15A branches on 14 AWG. Receptacles all go in 20A branches, even though they're only required in specific places like kitchens. Putting 14 AWG on a 20A overcurrent-protected circuit? You need to conform to the tap conductor requirements in Article 240. 16 and 18 AWG? Only on fixture wiring as defined in the NEC.
Guy I worked with he said high frequency switching power supplies can cause harmonics on the neutral wire get enough of those on a shared neutral overload it.
Fables.
how can that be legal the breaker will not protect that wire which it is to be doing?
Very informative video. Can you maybe demo how to correctly split off different gauge wires in these types of a setup? Is there a certain way that has to be followed to join different gauge wires together for the different circuits. For example -Are separate junction boxes needed when changing gauge - different from the ones that the switch or receptacle would reside in? I always thought it was bad to join different gauge wires together but this explains the theory how it can be safe in certain instances. Note - I am no electrician just your typical DIY type.
Glad to see this video. I prefer to up size to 12 even when it isn't required just for consistency if nothing else.
12 ga. minimum in my truck, and all receptacles are spec grade.
I HATE being called back because someone melted a receptacle by plugging 2 space heaters into it.
It';s also nice to not have to carry 45 more line items of inventory.
@@TimeSurfer206 exactly. Have all your material the same trade size and make your installation future safe. You never know what these people are going to do after you leave.
So, are you saying that in that particular parallel circuit that I could take 14/2 from the switch up to and through all the lights? I was always under the impression that if I started a circuit with say 12/2 I could not down size the wire size on the circuit
Use only the size cable the nec writes as minimum for whatever circuit/home run you are pulling. Only recommend pulling many extra circuits/home runs. Like one to the garage door openers.
Do you think NEC will change to mandate more receptacles? And power supply? Based on how everything is moving to electric: lawn equipment, cars, table saws & tools, E-bikes & scooters, all our electronic crap that needs charging- the whole gas stove debacle and heat pumps. It seems we need more than "one receptacle every 6 feet". Maybe a double duplex receptacle at every spot?
The short answer is yes. It takes time. The NEC now requires at least one receptacle outlet for each vehicle bay in the dwelling garage. This is due to the increase in the use of rechargeable batteries.
Future repair might be confusing with white and yellow wires in the same complex circuit.
I used 12 everywhere in my house. I could have used 14, but I already had the spool of 12 there. If you ever want to put in a ceiling fan, It's a good idea to run 12. I might have saved a little bit with 14, but the cost difference was negligible.
Do ceiling fans require 20 amp?
@@derekofbaltimore No. Ceiling fans use nowhere near 15 Amps.
If box fill isn't an issue!
Exactly, the cost difference long term becomes negligible and you get a much better wire for the life of the service. Same goes for using the higher quality commercial grade 20 amp receptacle outlets.
Actually, if you're doing a ceiling fan, you should run a 14/3 so you can separate the light and the fan at the switch box. Also you can get rid of those ugly pull chains. Absolutely NOT a 12/2 unless you are coming off a 20 amp circuit to be code worthy. There is absolutely no reason to run a 12 wire for a ceiling fan. Unless you have 16 or 18 of them on the same circuit. Most residential ceiling fans only draw 1 to a .5 of an amp.
The problem would arise if there was a malfunction in the device installed. In the case of a short it will start pushing more current all the way up to 20A before tripping the 20A breaker on a 15A wire. Now you are over rating that wire by 5A. Please explain how that is a good or acceptable thing. Not all shorts are dead shorts causing the breaker to trip immediately.
I ran 12/2 to all my outlets even when they are on 15 amp breakers.. but coming off the outlets that are also servicing lights, I run 14/2 .. everything coming out of my panel goes down below into my crawl space then up to the outlet ,back down into crawl space, back up to next outlet.. I have virtually no horizontal runs inside my walls.. (except where im powering a switch for lights, and that is only in the cavity on the other side of the same stud. ) I never put a 20 amp breaker to a 15 amp outlet .. really wasn't that much extra to run the heavier wire to all the bottoms..
That’s a good point about lights. You could run like a hundred LEDs on 18 gauge. They should really make smaller gauges of romex for these applications. Does code have any provision for this?
A sub panel or breaker/fused shutoff box.
Circuit protection (breaker/fuse) needs to be sized to the circuit. Code includes using all items to their UL listing and as described to be used by the manufacturer. Sizing the circuit breaker includes determining cable size (and mfg amp ratings) and the maximum device protection listed for each device on the circuit.
A receptacle will be listed simply as '15A' but an air conditioning condenser unit will really spell it out on the tag with "Maximum breaker/fuse/protection: 30A." I don't know recall seeing, and don't want to go check, if cable has a max amp rating. I'm sure they do list it somewhere. But cable is more amps vs length/distance/resistance... so it's simply codified as minimums. With enough distance, and voltage drop resistance and heat, with select amps, you could easily burn a place down following code.
My grandfather, who I apprenticed under, used to do it this way, 14awg switch leg on 20 amp circuit. Although theoretically okay, I would highly advise against it. Talk with your AHJ. It's very easy for an inspector to call this out and fail you. NEC makes it pretty clear not to put 14awg anywhere on a 20A circuit
Son just bought an old house in Portland with 100 amp service. Electrician quoted him 5200.00 to upgrade to 220. ? What is the procedure that would cost so much? Cheers. Ken
I am wondering how many electricians worry about voltage drop. The tester I used for testing boat 120VAC outlets imposed a momentary 15A load and showed me the voltage drop. On 100'ers, the voltage drop with 14 gauge wire and a 15A breaker was often in excess of 27%. And owners were wondering why their high draw motors kept failing prematurely. In my wife's custom built home the outlets furthest from the breaker box in the bedrooms had voltage drops of 15-20%. I am of the opinion that unless it is a circuit solely dedicated to lighting, all wiring in a house should be 12 gauge minimum!