I’m a licensed electrician. The more I learn about grounding and bonding, the more I realize I don’t know much about it. Grounding and bonding is incredibly complex. Nice video, Dustin !!! As usual, very informative. Cheers.
Just got my masters license two weeks ago, and I’ve been watching you ever since I got into the trade! You helped me out a ton with all the videos along the way! Thanks for all you do Justin
Nice explanation. I am so glad to hear your explanation of the code requirements for this. While I am not as good on code, I am an Electrical Engineer and I can explain why you don't want to bond the neutral to the ground in more than one place. In your example, the neutral (white) is bonded to ground at the main building and is run to the out building. That neutral wire will have current passing through it because of the load from the out building and thus its voltage will be different. Also, because of the inductance of the wire and because the wire is long, the voltage on it (both in phase and amplitude) will be different from the ground (which should have not current flowing through it). Thus, if you connect the neutral and the ground at the out building you will introduce a current in the ground. This can be a safety hazard. This issue is called a "ground loop" as you can see that the ground and neutral connected at both ends makes those wires into a circle (loop) that current can flow through.
The neutral conductor will carry the unbalanced load current from the sub panel back to the main breaker panel. The neutral is still a GROUNDED conductor and is "neutral" between both UNGROUNDED 'HOT' LEGS in a 240/ 120 volt 4-wire set of feeders.
@@electricianron_New_Jersey I agree that is how it works as long as you do not connect the ground to the neutral at the out building - which you should not do. All I was doing was explaining why - because though the neutral is still grounded, the inductance in the wire plus any unbalanced load will cause the neutral to be different from the ground at the out building.
Also, with the ground and neutral tied together at both ends you have turned that length of ground wire into a second neutral and the current that would normally flow on the neutral will now split itself between the two wires.
@jdilksjr and I might add that having current flowing on the ground has the potential to energize anything connected to that ground wire. That's an accident waiting to happen, and someone who touches an energized equipment case is going to get really pissed, shocked, or electrocuted. One or two of these results may have a secondary effect of someone else getting their ass kicked while being cussed out.
During the storm season in California, I have wired a 13K watt generator to a manual transfer switch to run certain loads. The generator has a floating neutral but the manual says to bond the generator frame to the neutral wire as well as drive a grounding conductor in the ground. The 240 volt plug going to the receptacle that connects to the transfer switch ultimately (as you know) connects to the service panel. My question is, "why would I bond the neutral to the ground and frame of the generator as well as stick an additional grounding electrode in the ground?". Thanks and enjoy the whole series! Roger Peterson, Monterey, CA
There are lots of videos that explain how grounds & neutrals should not be bonded at a sub panel, and how subpanels in a separate building require their own grounding electrodes (whether a rod or concrete encased etc). Few of them explain *why*. Thank you sir.
Although I was mostly just looking for info to make sure i was satisfying NEC requirements for a set of small greenhouses we have with new power, the last 5 minutes of this video was the most informative information regarding grounding vs bonding I have ever come across. Thank you.
Today I learned what haberdashery means. But seriously, you are paving the way to my license and to become a well rounded electrician. Thank you, Justin, really.
Very good video! Thanks! My meter is on the outside perimeter wall and to connect my house, my "electrician" actually told me i should bond the neutral/ground at both the meter and in the house panel... i sounded wrong but since i am only a hobby electrician, i assumed he knew what he was talking about! There is so much bs about grounding and bonding! So thank you for all your videos!
Excellent; all I would add is that, additional ground electrodes (earth connections) can be added to provide additional support for electronics/radio and communications equipment etc. or to create equipotential environments for step and touch potential mitigation, static electricity mitigation etc. (all special applications) - BUT - all ground electrodes must be BONDED together in a Single-point grounding topology (think of the branches or roots of a tree) which runs back to the panel and with no double-bonding of neutral to ground anywhere in the system. The IEEE Emerald standard speaks to these special applications while being completely compatible with the NEC. NO isolated grounds please - they will cause problems. Also for those who might be interested Motorola developed the PANI system for segregating dirty and clean grounds for highly specialized telecom and computer applications. For the electronics engineer or technician, grounding is a big topic. This was a great coverage of the code aspects and perfect for the guy or gal who just wants to run power to his garage, barn, etc. for ordinary purposes. The video was informative and accurate. When all is done, you can check for neutral to ground potential and for objectionable current flowing on bonding conductors as part of a power quality audit. Using a ground resistivity meter can help verify that you have an effective grounding system. Obtaining say 1 or 5 ohms to ground is an engineering objective for certain sensitive applications (not your ordinary garage necessarily). Other special rules apply to bonding gas appliances, fuel tanks, around water meters etc. Stray voltages can be created by neutral return current flowing through the earth back to the transformer on the street (or wherever) due to the nature of our neutral-grounded power distribution system. Animals might be sensitive to stray voltage and special methods can be employed to mitigate this phenomenon. Lightning rods used to protect a building also have special engineering, construction and code requirements. Generators and transfer switches also have special grounding and bonding requirements. Devices inside electronic equipment such as SPD/TVSS, GFI's and EMI/RFI filters, even good old fuses and breakers will rely on good earthing and bonding practices to perform some of their functions - mitigating transients and noise in both Normal and Differential mode and quickly isolating fault currents. Make sure all utility cables (TV, phone, hydro etc.) are all bonded together at a common point. Termination to ground, of shield wires in communications and control systems cabling is highly misunderstood and is a whole separate topic. I've had great success with installing a 10 ft x 3/4 inch copper clad UL rated ground rod in a well of ground enhancement material (several brand names exist). Stay away from galvanized ground rods. Space electrodes properly and use rods over plates where feasible. Use good quality connections like UL rated crimp-on devices or exothermic welding to make your connections. Install rods in an inspection well where feasible. Make sure that the ground electrode conductor running back to the panel and the bonding conductors are of sufficient AWG. Avoid making loops in your bonding topology. Lots to know about grounding and bonding. Knowledge and understanding of both theory and practice are the keys. Good engineers, techs and electricians do not discount either - theory and practice should converge if you know what you are doing. In the end Safety is the priority. Just knowing the code is not always enough. Remember that the code is a minimum requirement for safety (mostly fire and shock). Crack open those textbooks and understand the electrical theory behind what you are doing. Other parts of the world have different grounding standards and systems and so if you have purchase a milling machine made in China, you may want to look at the electrical schematics first. Always remember that electricity, like water, will take every path it can - not the path of least resistance (a dangerous myth). It will happily run through your body to the earth and kill you if you give it a chance. Wear insulated work boots and gloves where required and don't assume that a ground wire does not have current running through it. Thinking that touching ground wires is always safe, might be your only and last mistake (documented fatalities have occurred where disconnecting a ground wire from an electrode while the neutral was bad and all of the load current was returning to the transformer through the ground). Stay curious, always ask why I am I doing this, this way and is it code compliant a a minimum; use PPE good quality tools and materials with the proper ratings. This channel is an excellent resource; please keep making videos and thank-you. Happy grounding. Daniel Lawlor.
I really appreciate your explanations. When I was a worm apprentice my journeyman was a great teacher. He was patient and drew things out like you do and took the time to explain to us worms. He’s a master now and has his own company doing well, so I’m glad to see there are teachers like you and him out there. Being a sparky, there’s a lot to know
We had a job once where we were installing a sub panel in a shed that was directly adjacent to house. The main panel was about 10 feet away and there was less than two feet of space between these buildings. We didn’t run a separate ground because our lead misunderstood the code but when the inspector came out and mentioned it he took a 2x4 and nailed it up between the buildings so they could be considered the same structure. The inspector laughed and passed it. I’m pretty sure the homeowner took the stupid board down as soon as we left but that’s not on us I guess.
Good. Thanks for continue to discuss return path thru earth doesn’t trip breaker . Regarding the other video with energized ground rod I was hoping someone would repeat but add a 3 point resistance to ground on ground rod. Then measure current flow and see how v=ir is. I’ve used the video in my explaining
Here in GA, we have to put a grounding electrode in every pole. When we do new pole locations, this is the biggest thing they want to see. We have to bond to the rebar cage and show this before we can pour concrete. Then we have to take the EGC and bond it to the pole itself, to the grounding electrode, and to the EGC going up the pole.
A couple of points that I would add to what was covered (just an amateur who has some experience in these things) ; as a basic point of clarity , the primary reason for the installation of a grounding leg being installed as part of your circuit(s) is for it to pick up stray current/arcs/sparks(ing) that do not find their way to the neutral or register as an overload within the general parameters of the typical operation of the circuit ; that can be a stray current which originated from the supply circuit or as with the case of lightning it could be of a point of origin from outside of the intended design (in which case we could be talking about an amount of energy far in excess of the capacity that your system is designed for) the grounding system is there to allow for/provide a means to at least aid in providing a point of discharge for that stray current and/or potential excessive overload , it's not intended to be a main active conductor during normal operation. One other thing that I think might be worth mentioning is that the general indication in the video was that "grounding rods" are not "good" conductors (or shouldn't expect to be good conductors) I tend to believe that there's a pretty considerable amount of variability that could exist in that area . A person could put a simple 1/2" or 5/8" ground rod down somewhere in dry soil which as he was indicating may not have a great capacity to conduct , or you may find as I see at times in my area that the electrical service is grounded to a steel well casing in an area where it may only be a few feet to the ground water table and who knows what the soil structure brings to the equation (sometimes this could be the circuit structure without a neutral going back to the incoming supply source ; NOT something I recommend) . But the point to try to address for the purpose of having a smooth functioning system with the basic safeguards being discussed is to incorporate the existence of a grounding pathway sufficient to provide an extra measure of protection from "adverse" system discharge(s) &/or excessive overload but not one which is going to interfere with normal , preferred flow of current through your circuitry. Different areas may tend to have different preferable methods for sizing and installing a grounding system for your area ; as was indicated in the video it's likely to be a good idea to consult with an electrician or inspector in your area if you need help getting it sorted out.
Howdy. Yes. In older systems where the riser/feeder uses the same wire for ground and neutral a soil electrode at the aux. building is absolutely mandatory. In a newer system with separate ground and neutral the electrode is not so important if the riser is very short, say 40 feet or less. Bonding of conductive parts is essential in the aux. though. But yes. The Code says there shall be an electrode. If there is just a branch to the aux. to feed a few sockets, bonding of conductive parts is highly recommended. No matter if the branch is an old 2 wire or a newer 3 wire cable. Regards.
For installing pool heater so i understand. Main panel breaker = cut off panel = sub panel with gfi and ground wire to earthing rod = separate meter to measure power usage of heater = pool heat pump heater which case housing has its own separate ground wire to earth? Standard 220 volt wiring through out with boded main panel only.
For the longest time I always thought that the ground rod would take the load first as it is the closest circuit. However, as you have mentioned the connection to the transformer is the lowest impedance circuit there is so it actually takes that(with some very small current I suppose going to ground). THUS bonding neutral to ground is vital as it will also coincidentally trip the breaker on the way out. Amazing information!
Another excellent correct video! NEC indicates that you should NOT put ground rods on lighting poles. It came up in a Code class I took several years ago. The consulting engineer in the class got his mind blown when he found out he had been spewing them for years incorrectly.
I'm an apprentice so I was just the labor, but about 3 months ago we did exactly that. Rod in a lighting pole. Good to know. happen to know the section in the code?
Great tutorial, colors and your ability to simplify the code (black ink on white paper) is very helpful. We've read papers on ground current running back to the Utility company, via the neutral connection. Would be helpful if you were able to elaborate on that, and perhaps dispel myths or misconceptions about it.
Been working this issue for weeks since I discovered it with my shelter house. Unfortunately the feeder line from the house to there didn’t have a ground run to it (not to mention he didn’t bother running one from the service connect across the driveway to the main house). Electrician has already come out and it’s planned to all be redone starting the first). This ain’t cheap but I’ll feel better having it done right.
Just went through essentially the same thing. No ground in the undersized feeder to the metal shop building and no ground rod at the shop building or the house. Now it's been corrected with a new feeder install exactly like shown in the video along with changing out the fire hazard Federal Pacific house panel with a modern one. Agree it's not cheap at all but I'm happy with the work done.
Great response. I wired a greenhouse beside a main building last summer, here in Canada. The greenhouse was fed by two circuits from the main building panel, with a system ground wire from the main building which was not attached to the metal of the greenhouse. There is no disconnect at the greenhouse. It was located about 50 feet away from the ground rods for the home. Our electrical code is a little vague, so before I poured the concrete pad I laid in a ground plate, and I attached that to both the building and the feeder ground wire. To my surprise, the inspector required me to disconnect the grounding electrode from both the greenhouse frame and the ground wire from the home before he would pass it. His concern was something about stray currents between the two grounding electrodes causing issues.
that's because you only have branch circuits, not a true feeder with a panel. In many areas they might still ask that the building metal and slab rebar be bonded to each other, and then to a ground rod... but NOT tied to the electrical. (unless there's a panel)
If I recall, in the US you're only allowed one feeder to an outbuilding, with a few exceptions. They would want us to put in a subpanel at that point and then run out multiple circuits from there.
@@kevinmach730 ... in hindsight, those two circuits may be a run of 12/3, in which case a shared neutral would actually be 240 volts. IOW, qualify as a feeder rather than 2 separate branch circuits. Two conduits and two different breakers might slide, but I would be asking the local inspector if that would pass code.
@@rupe53 I considered something similar for my own outbuilding, but since it just didn't make sense to go through all that work to only have the power provided by 12awg wire. A few people reminded me the work is same more or less either way, if you have the space in your main panel, might as well opt for a small sub panel in case your needs change later. I am glad I listened, because I was able to add a 240v breaker for a heater and air conditioner. Edit: Obviously, the wire was double the cost. and highway robbery at current prices. Plus I needed schedule 40 conduit, which you would get away without if you ran UF. But in my area, that requires digging down 2 feet as opposed to 17 inches.
@@kevinmach730 ... yes, it costs more, but in the long run you get MUCH more for a similar effort on the job. It's just a typical case of pay me now or pay me later to do it again.... so why bother with the shortcut.
A similar situation exists where the "external structure" is a well pump house. Usually the pump house is fed using only a single (often 240v) branch circuit, in which case the exception clause of 250.32 applies and a grounding electrode is _not_ required. But I've always errored on the side of caution in this situation and installed a separate grounding electrode. It only costs a few dollars more but I believe significantly increases the safety factor.
if new install I usually try install a sub panel in some well houses, pump on a separate 240V breaker, service outlet in case heating needed other use, and light on a separate circuit (4 slots) and a few install permanent 240V heating also so...
Amazing channel, love the highly detailed content! For the next video, could you please talk about separately derived systems (like stand-by generators), and whether they need ground rods or not, and whether their neutral needs to be bonded to the enclosure? Thanks.
I am a lineman and we put ground rods at every transformer and riser, so when my son built his detached garage with a panel I assumed he needed a ground rod , but the inspector (Ontario) said to disconnect it.
I install signs for a living. We typically only install ground rods for signs that have electronic message boards. Mainly for “warranty” purposes but in actuality it’s for peace of mind on the boss’s end haha.
this ground conductor will also help prevent differences on ground potential. have seen computer cable burned out by equipment with a 0.5v ground potential difference.
From what I've understood, once power has left the meter, the tie from neutral to ground should only occur once, which is at the main panel. Doing otherwise opens the risk of objectionable current. Earthing should happen to each sub panel, in most cases. If wiring enters another building without a panel--no further branches, then further grounding isn't necessary.
Hmm In australia it’s kinda similar. We have MEN link earth and neutral at the main switchboard. The earth should be sized to the mains capacity. You do not install multiple earthing systems you can only have one at the origin
question: Metal industrial building. 480v 3 wire delta service therefore no neutral coming into building. The 240v transformer has the neutral and grounding conductor bonded to to the metal building. Is a ground rod also required? Awesome channel for a non electrician!!
Great information! Can you clarify this? What if an out building has a sub panel feeding another smaller sub panel in the same out building, would both sub panels require their own grounding rods? Would only the sub panel connected to the main be the only panel needing a ground rod? It is my understanding that only if the sub panel resides in the same building as the main will it not be required to have its own grounding rod. What is correct?
A few years ago I ran a 100A sub panel from my house’s main panel out to my shed. It was fully permitted work and inspected by the local city inspector. I’m glad he had never watched this video because there was definitely never any discussion of installing a grounding rod! Now I guess I won’t sleep well until I go install one. 🤦🏻♂️🙄😂
Speaking as an EE, you can't have too many grounding electrodes. If there's *any* question, put in another ground rod. You want that green conductor to be as close to earth potential as possible, which is why it's not bonded to neutral anywhere other than the main panel. Neutral wires carry current, wires have resistance, and current through a resistance has voltage. The part about not using the earth as the grounding conductor reminded me of what I used to do as a teen when I wanted to go fishing. (Don't try this at home.) I'd water a bit of the yard, push a steel rod about a foot or two into the ground, and connect that rod to 120V. In a few minutes, the worms within about 5 feet of the rod would be wriggling on the surface, where I would just pick them up.
Why would you not want the most efficient path back to the source? In this application it seems excessive grounding electrodes will prohibit the ground fault from being detected and opening the circuit, increasing the risk of being shocked.
Thanks Dustin, great info. There has to be a reason that each building needs a ground rod. What bad stuff can happen if the secondary building subpanel is treated like a subpanel within the main building, no ground rod and bonded ground + neutral?
Hello dustin my elec instructor, can you do a full video on panel branch cct balancing ,what appliances and rooms you would put on the L1 (A)and L2 (B) phase in a single phase domestic system for the lowest neutral current.
Hey! I'm in florida, and wanted to run this by you, because I have had this argument online before. This is in the case of a Solar system, that is fed by a line-side tap, and not a breaker. Engineering, as well as inspectors, require a lineside tap from the main service panel (bonded) to feed a fused disconnect, which is also bonded. I see it as a "seperate" 1st means of disconnect, due to the inspectors and engineering. We are using pierce taps on the service lines on the line side of a main service panel, so upstream of the main disconnect. So we are branching unfused lines from the meter, creating a secondary system. Sorry for rambling, but in this case, we always and must bond our neutral and ground in the fused disco, and keep the MSP bonded as well. I see electricians arguing that you cannot have 2 1st means of disconnect, and that only the msp should be bonded. What is your take? I only equipment ground a disconnect (non-fused) when I'm feeding from a breaker.
BTW, I Love your page, been watching for years! I've been a solar installer, working under our electrician's lisence for 5 years, and am soon going to apply as an apprentice and work towards my journeyman's. I have upgraded service panels, changed out outlets, installed switches, lights, sub panels, ATS's, even meters and meter mains, all along with our solar and storage systems. I can't wait, and believe the years of watching your videos has a lot to do with why I am where I am today. Not a part of your discord or your advancement classes but believe I will be joining as soon as I officially make the switch! Thanks bro!
Ugh. Just rewatched the portion where you're talking about multiple buildings and then wind and solar and realized you said that those are all separately derived systems. Which is exactly what my comment said in 100× words. I've always been confident that I was understanding it correct, just see ppl argue it wrong sometimes on electrician pages. Lineside tap to disco, disco must be fused and neutral must be bonded to ground. If you read all this... I'm surprised, and thanks! Lol
Question. We have a house built in 1956 with no grounding wires, no ground bar, no ground to the foundation rebar, etc. The service entrance is to a meter, then to a main panel with a 100 amp breaker then to a panel in the house with another 100 amp breaker then to two in-house subpanels which connect to the circuits. Nowhere do I see the neutral bonded to any of the panels which makes sense since there are no grounds. We have another subpanel at our wooden shed which is connected to the main panel through a 40 amp breaker to #8 in the subpanel with its circuits protected by a 30 and 15 amp breaker. It also has a grounding system i.e. a ground buss connected to the subpanel and to a ground bar with #8 wire. An electrician friend suggested I connect the neutral and ground busses in the shed subpanel. I am not sure that is a good idea. Comments?
Wow...I need to fix my metal building, LOL. I had a 100A sub-panel/distribution panel on a pole with L1/L2/N/G from the main in the house. I added a metal building (34x28) on a slap next the panel and actually moved the panel inside my structure. everything is as you show in 250.32(b) but I do not have a grounding rod at the metal building and my ground (green) is not connected to the metal building just to the ground strip in the sub-panel.
HELP! I have a sub panel in my garage (fuses 🤦♂️) that I'm replacing. I have to run new feeder with an egc. The existing buried pvc conduit contains feeder hots and neutral (only 10ga with no egc 🤦♂️), travelers for a 3-way light switch back at the house, and a phone line 🤦♂️. I'll be replacing the 3-way with a smart switch and deleting the phone line. The problem I have is that the sub panel is in the middle of the garage slab with no grounding electrode. Will I have to drill the concrete and pound a 20' electrode? The closest exposed earth to the panel is over 15' away. There IS a buried copper water line to the garage, within 3' of the sub panel. Love your content! Keep it up.
I guess my questions is, in a detached garage or any building, if I install an MLO panel with no main breaker, do the ground rods for that building attach to the mlo or back at the service disconnect at the other building
If you have existing outbuilding serviced by a three wire feeder (two hots and a neutral) with no equipment grounding conductor and the outbuilding doesn’t have any metal connecting it to the main building with the service, is it correct that you need a grounding rod at the outbuilding and you bond the ground and neutral at the outbuilding subpanel? Adding an equipment ground conductor between the two would require trenching through an existing driveway so wouldn’t be easy.
I'd love to see a video of you actually wiring the subpanel. As you explained, the neutral does NOT tie to the ground inside the subpanel the way it would in the main house. If I look at the panel inside my house, both bare (ground) and white (neutral) wires can be attached to the same locations in the panel, and those are all attached to the panel itself. If I understand what you've said, that's different in a subpanel. The grounds will be tied together and grounded to the panel, but the neutral wires will NOT. Do subpanels thus come with one set of lugs for the bare ground / green and a different set of lugs for the neutral / white?
When you purchase a breaker panel to use in an out building as a sub Panel.... most often you have to buy with the panel, and extra grounding Bar, for that brand of panel. Some brands come with them, but most do not. It should come with screws and the panel should have a place to attach it. Must use the screws that comes with the grounding bar. This will be your "Grounding" (Green Wire) connection for all equipment grounds. The Neutral Bar already in the panel is your "Grounded" / Neutral Bar, for all of your neutral wires, (white). Remove the Green ground screw from the Neutral Bar, or jumper, which ever it has. You don't need them. The Grounding Bar you install will be Bonded to the Breaker panel "can" using the screws that come with it.
Great info, I think it answers my question but I have a specific scenario and I'd like your response. I'm connecting my "shop" (a prefab shed) to a 50Amp RV outlet. From my main service panel I've wired a 50A 240v outlet, then run a 100' Southwire 50A extension cord (6/3+8/1 ground) to a Reliance 50A inlet box, which can then be wired directly to a sub panel. (No transfer switch, no generator, I'm permanently powering the shed via the extension cord from the outlet.) The "sub" panel is actually a Square D 100 A Main Breaker Panel so I have my main disconnect. There is no ground bus bar on that panel. I assume I have to attach one separately, and hook up the equipment ground wire from the inlet box to it. So the main question is: do I need to stick an electrode in the ground and then connect that to a ground bus bar, or can I just attach the 8/1 grounding wire from the main panel to the ground busbar on the sub panel and call it good? Your video seems to say I need to do both: add a ground bus bar to the sub panel, then drive an electrode into the ground and tie it to that bus bar, then connect the equipment ground from the feeder wire as well. But this seems like multiple paths to ground, unless I'm totally muddled. Thanks!
Great video. I'm in southern Missouri and there are basically no inspections here, except for a few municipalities. I see URD for feeders a lot, with no EGC. They just drive a rod. I fix a good number of these.
@Electrician U have you used the Combo #1, #2 bits before and what do you think of them, they are found in the Klein 32305 Tool. Also same for the The Klein ET310 what are your thoughts on those?
Do you have a video about how to install a service discount after the meter? Upgrading our electrical. House now has a main and a sub panel. Want to know how to bond and ground.
What is required where a three wire USE triplex is run from the house to free standing frame structures without a seperate grounging conductor as in an older system? Do you have seperate grounding rods for each out building and do you bond wirh neutral in them?
I had an inspector tell me that only one continuous wire can be run for the ground rods; it must pass thru the first and terminate on the second rod. You cannot have 2 separate wires, one going to each rod. Is that a local thing? Also: 6' is the minimum space between ground rods, is there a maximum distance? If two panels are located relatively close to each other, can they share the same 2 ground rods or do they need their own? Conversely, if you had 4 ground rods, 2 ea. for main and sub panels, would it be better to directly connect them all together? If you have a ground wire directly fixed to a water pipe, can you attach a ground rod to the other end of that pipe, or does that rod require a direct wire to the panel? I know these questions may seem obvious, but codes are not always so obvious. Thanks for your shows!
By tying the neutral and ground together in those other buildings, you’ll probably end up with some strange goings on that will affect micro electronic equipment; such as musical equipment, sound and lighting equipment, computer equipment.
My welder acts up in my detached garage and I wonder if this could be the culprit. It has a sub panel and I'm wondering if the neutral and ground bars are bonded. The welder welds fine for about ten minutes and then starts sputtering and becomes useless. It is not hitting the duty cycle limit, as I have tried two different welders and they both have the same issue.
Thanks for the great video, this came up on a job site just this week (in Washington state.) Is there a reason why you drew a disconnect on the outside of the accessory building fed by the feeders? I'm reading 225.32 saying the disconnecting means can be installed inside or outside the building being served. Appreciate your insight!
What about on a 400 amp service? Installed disconnect at the meter and ran conduit out to a barn with its own 200 amp panel. Can I ground the disconnect at the first set of ground rods or do I need to drive 2 more ground rods out at the barn?
Hey love the content I work in the solar industry and something I've been instructed to do has been confusing me a bit. I've been told in the past the reason we do this is due to some inspector somewhere in Florida. We do interconnections with generator systems and tap the line side of ATS's to feed disconnects for our sub panels. I've been told that when we do this the PV system becomes a service and that we're supposed to run a ground rod and bond our grounds/neutrals in the disconnect. (Which is fused). Is that correct? The other electricians I ask never really give me a solid explanation. I've always been under the impression that the EGC should be bonded to the ATS and the grounds and neutral separated. Just because the transfer from utility to generator doesn't mean that the PV suddenly becomes a service.
Have a question about grandfathered systems. Come across a lot of sub panels with only 1 conductor used for neutral and no ground. Should those have a ground rod installed as well? Inspectors call this one out a lot in my area.
I noticed there is some electrical work that was done to my house unpermitted years ago before I bought it. Specifically a 240V outlet and a electrical panel inside my outbuilding. I was wondering if the fact that these were not permitted May post problems if I were to sell the house one day?
depends, in my area no permit needed for doing yourself, unless a major remodel but usually just building permit then all aspects are inspected, but working only adding a outlet or other simple things no permit needed so check with local AJC if permits are needed for simple electrical if doing yourself if allowed.
Thanks 🙏for sharing, even though I live in the UK physics is always physics. Do you have a video on separately derived systems perhaps? I built a solar shed which can provide power and/or be provided from the main building where the Victron inverter is supposed to lift the neutral to ground when connected to the mains. However I don't feel safe non having the two ground electrodes bonded together so I have arranged for an automatic contractor for phase, neutral and ground change over so to keep the two systems totally independent. However if the inverter is used for charging as well as assisting the all system would run on the main building earth bonded to the neutral at the service and I would still have the secondary grounding electrode connected to the PV system. Should I just bond the two grounding rods and not worry about it or have I done the right think by keeping the two systems grounds independent from each other?🤔
Can you do a video explaining how to wire up a RV/travel trailer with shore power (120v) to a panel in the RV? When to bond the ground and neutral, at the rv panel or is that considered a branch panel and you consider the pedestal the bonded panel?
It would be a sub-panel. The neutral and ground must not be bonded in that, otherwise current flowing in the neutral will be split between it and the grounding conductor, so there will be some potential on "grounded" metal cases.
What if you have this same scenario except your sub panel has a main breaker instead of a separate disconnect. The feed from the house feeds the main breaker.. would you connect your ground rod and the equipment grounding conductor on the ground bar in the sub panel?
This is interesting I built a garage that became my main service drop location (i moved the service meter and drop to the garage) making my house a subpanel of my garage via a 100amp feeder. My electrical inspector made me disconnect my original grounding electrode conductor. His reason was there should only be one ground at the source (service). Ie i have aabandoned rods at the house and a working ones at the garage (new service drop) Was this incorrect?
I'm amazed at the contradictory information online regarding RV pedestals requiring ground rod or not. Has this been clarified in the code or is there still an argument over whether the pedestals are structures or equipment. I see grounding rods at RV park pedestals all the time, but it seems by your excellent explanations that this does not add touch protection, etc, but rather only lighting protection of equipment? Some online information even argues that grounding rods at the pedestals down stream of the grounding rod at the source panel will fail inspection. So confused.
What makes, or should I say... what causes a grounding electrode to smoke? Have you ever seen that happen? I came upon a house for a service call where the customer says the ground is arcing, popping, and smoking around the grounding electrode. When I arrived, the grounding electrode is about a foot over from a 3/4" rigid conduit that goes to his hot tub, and the underground feed to the subpanel inside the garage is about a foot to the left of that as well. He said he turned off the breaker in the house main breaker (100A) that feeds the subpanel in the garage. Yet is was still smoking when I arrived. The grounding electrode conductor is attached to an equipment grounding lug at the left bottom corner inside the subpanel cabinet. It was not evident that it existed from outside. There was some recent remodeling going on, so everything was finished (walls, etc). When I opened the cover and saw a black wire in the lug, I took a meter out, thinking someone hooked a hot wire up to the cabinet lug??? Didn't make sense. After careful examination I find it was attached to the grounding electrode. The area around the grounding electrode was still smoking....even with the power off that fed the subpanel, so I removed the wire rom the lug (No voltage on the wire, by the way) taped it up and the smoking stopped. Can you explain that one?? I have to say, in my 42 years of being an Electrician with industrial, commercial, and residential experience.... I don't remember ever seeing something like this, and I thought I have seen it all! God, I love being an Electrician!!! It never gets boring, and I can't get enough of it. I didn't even charge the guy for that service call.... I must have chalked it up to a new learning experience.
I see on your diagram that the ground rod conductor is connected to the disconnect and not the subpanel? Does it matter which or can it be either or does it have to be both?
I am considering updating wiring for my garage, currently its fed by two hots and a neutral, No ground. Can I replace the fuse box with a breaker box and add grounding rods at the garage without tying it the main house system and still comply with code somehow? From a non-code safety stand point would it increase safety to add a ground at the garage or is there a hazard I am missing?
I'm still confused. I understand the sub panel in the remote building needs a ground rod, but do I need a separate ground rod for the disconnect on the pole outside the building?
IANAE, but I would think there has to be some kind of disconnect, whether a separate switch or a main breaker in the top of the sub panel. Interesting question, looking forward to seeing a better answer.
I’m a licensed electrician. The more I learn about grounding and bonding, the more I realize I don’t know much about it. Grounding and bonding is incredibly complex. Nice video, Dustin !!! As usual, very informative. Cheers.
Extremely informative and well taught. You sir, have a gift from God to teach aside from being a tradesmen.
Just got my masters license two weeks ago, and I’ve been watching you ever since I got into the trade! You helped me out a ton with all the videos along the way! Thanks for all you do Justin
Justin 😂
@@erich1380 damn j ain’t even close to d 😂
I forgot
Justin Seltzer
@@benmardis8237 Master blaster
Nice explanation. I am so glad to hear your explanation of the code requirements for this. While I am not as good on code, I am an Electrical Engineer and I can explain why you don't want to bond the neutral to the ground in more than one place. In your example, the neutral (white) is bonded to ground at the main building and is run to the out building. That neutral wire will have current passing through it because of the load from the out building and thus its voltage will be different. Also, because of the inductance of the wire and because the wire is long, the voltage on it (both in phase and amplitude) will be different from the ground (which should have not current flowing through it). Thus, if you connect the neutral and the ground at the out building you will introduce a current in the ground. This can be a safety hazard. This issue is called a "ground loop" as you can see that the ground and neutral connected at both ends makes those wires into a circle (loop) that current can flow through.
The neutral conductor will carry the unbalanced load current from the sub panel back to the main breaker panel. The neutral is still a GROUNDED conductor and is "neutral" between both UNGROUNDED 'HOT' LEGS in a 240/ 120 volt 4-wire set of feeders.
@@electricianron_New_Jersey The unbalanced load on the neutral does not correct a ground loop though.
@@electricianron_New_Jersey I agree that is how it works as long as you do not connect the ground to the neutral at the out building - which you should not do. All I was doing was explaining why - because though the neutral is still grounded, the inductance in the wire plus any unbalanced load will cause the neutral to be different from the ground at the out building.
Also, with the ground and neutral tied together at both ends you have turned that length of ground wire into a second neutral and the current that would normally flow on the neutral will now split itself between the two wires.
@jdilksjr and I might add that having current flowing on the ground has the potential to energize anything connected to that ground wire. That's an accident waiting to happen, and someone who touches an energized equipment case is going to get really pissed, shocked, or electrocuted. One or two of these results may have a secondary effect of someone else getting their ass kicked while being cussed out.
During the storm season in California, I have wired a 13K watt generator to a manual transfer switch to run certain loads. The generator has a floating neutral but the manual says to bond the generator frame to the neutral wire as well as drive a grounding conductor in the ground. The 240 volt plug going to the receptacle that connects to the transfer switch ultimately (as you know) connects to the service panel. My question is, "why would I bond the neutral to the ground and frame of the generator as well as stick an additional grounding electrode in the ground?".
Thanks and enjoy the whole series!
Roger Peterson, Monterey, CA
There are lots of videos that explain how grounds & neutrals should not be bonded at a sub panel, and how subpanels in a separate building require their own grounding electrodes (whether a rod or concrete encased etc). Few of them explain *why*. Thank you sir.
Although I was mostly just looking for info to make sure i was satisfying NEC requirements for a set of small greenhouses we have with new power, the last 5 minutes of this video was the most informative information regarding grounding vs bonding I have ever come across. Thank you.
Today I learned what haberdashery means.
But seriously, you are paving the way to my license and to become a well rounded electrician. Thank you, Justin, really.
Read your comment and was on the edge of my seat till the end of the vid.
I wanted to let you know your passion for this is amazing and I’m glad for it.
Very nice to see someone actually referencing the NEC.
Very good video! Thanks!
My meter is on the outside perimeter wall and to connect my house, my "electrician" actually told me i should bond the neutral/ground at both the meter and in the house panel... i sounded wrong but since i am only a hobby electrician, i assumed he knew what he was talking about!
There is so much bs about grounding and bonding! So thank you for all your videos!
Excellent; all I would add is that, additional ground electrodes (earth connections) can be added to provide additional support for electronics/radio and communications equipment etc. or to create equipotential environments for step and touch potential mitigation, static electricity mitigation etc. (all special applications) - BUT - all ground electrodes must be BONDED together in a Single-point grounding topology (think of the branches or roots of a tree) which runs back to the panel and with no double-bonding of neutral to ground anywhere in the system.
The IEEE Emerald standard speaks to these special applications while being completely compatible with the NEC.
NO isolated grounds please - they will cause problems. Also for those who might be interested Motorola developed the PANI system for segregating dirty and clean grounds for highly specialized telecom and computer applications. For the electronics engineer or technician, grounding is a big topic. This was a great coverage of the code aspects and perfect for the guy or gal who just wants to run power to his garage, barn, etc. for ordinary purposes. The video was informative and accurate.
When all is done, you can check for neutral to ground potential and for objectionable current flowing on bonding conductors as part of a power quality audit. Using a ground resistivity meter can help verify that you have an effective grounding system. Obtaining say 1 or 5 ohms to ground is an engineering objective for certain sensitive applications (not your ordinary garage necessarily).
Other special rules apply to bonding gas appliances, fuel tanks, around water meters etc. Stray voltages can be created by neutral return current flowing through the earth back to the transformer on the street (or wherever) due to the nature of our neutral-grounded power distribution system. Animals might be sensitive to stray voltage and special methods can be employed to mitigate this phenomenon. Lightning rods used to protect a building also have special engineering, construction and code requirements. Generators and transfer switches also have special grounding and bonding requirements.
Devices inside electronic equipment such as SPD/TVSS, GFI's and EMI/RFI filters, even good old fuses and breakers will rely on good earthing and bonding practices to perform some of their functions - mitigating transients and noise in both Normal and Differential mode and quickly isolating fault currents. Make sure all utility cables (TV, phone, hydro etc.) are all bonded together at a common point. Termination to ground, of shield wires in communications and control systems cabling is highly misunderstood and is a whole separate topic.
I've had great success with installing a 10 ft x 3/4 inch copper clad UL rated ground rod in a well of ground enhancement material (several brand names exist). Stay away from galvanized ground rods. Space electrodes properly and use rods over plates where feasible. Use good quality connections like UL rated crimp-on devices or exothermic welding to make your connections. Install rods in an inspection well where feasible. Make sure that the ground electrode conductor running back to the panel and the bonding conductors are of sufficient AWG. Avoid making loops in your bonding topology.
Lots to know about grounding and bonding. Knowledge and understanding of both theory and practice are the keys. Good engineers, techs and electricians do not discount either - theory and practice should converge if you know what you are doing.
In the end Safety is the priority. Just knowing the code is not always enough. Remember that the code is a minimum requirement for safety (mostly fire and shock). Crack open those textbooks and understand the electrical theory behind what you are doing. Other parts of the world have different grounding standards and systems and so if you have purchase a milling machine made in China, you may want to look at the electrical schematics first.
Always remember that electricity, like water, will take every path it can - not the path of least resistance (a dangerous myth). It will happily run through your body to the earth and kill you if you give it a chance. Wear insulated work boots and gloves where required and don't assume that a ground wire does not have current running through it. Thinking that touching ground wires is always safe, might be your only and last mistake (documented fatalities have occurred where disconnecting a ground wire from an electrode while the neutral was bad and all of the load current was returning to the transformer through the ground).
Stay curious, always ask why I am I doing this, this way and is it code compliant a a minimum; use PPE good quality tools and materials with the proper ratings.
This channel is an excellent resource; please keep making videos and thank-you. Happy grounding. Daniel Lawlor.
Great info. Clearing up a lot of questions. Thank you.
I really appreciate your explanations. When I was a worm apprentice my journeyman was a great teacher. He was patient and drew things out like you do and took the time to explain to us worms. He’s a master now and has his own company doing well, so I’m glad to see there are teachers like you and him out there. Being a sparky, there’s a lot to know
We had a job once where we were installing a sub panel in a shed that was directly adjacent to house. The main panel was about 10 feet away and there was less than two feet of space between these buildings. We didn’t run a separate ground because our lead misunderstood the code but when the inspector came out and mentioned it he took a 2x4 and nailed it up between the buildings so they could be considered the same structure. The inspector laughed and passed it. I’m pretty sure the homeowner took the stupid board down as soon as we left but that’s not on us I guess.
Good. Thanks for continue to discuss return path thru earth doesn’t trip breaker . Regarding the other video with energized ground rod I was hoping someone would repeat but add a 3 point resistance to ground on ground rod. Then measure current flow and see how v=ir is. I’ve used the video in my explaining
Good. Good. Good. That's the important topic. More about it. Always. Thanks so much!
Here in GA, we have to put a grounding electrode in every pole. When we do new pole locations, this is the biggest thing they want to see. We have to bond to the rebar cage and show this before we can pour concrete. Then we have to take the EGC and bond it to the pole itself, to the grounding electrode, and to the EGC going up the pole.
A couple of points that I would add to what was covered (just an amateur who has some experience in these things) ; as a basic point of clarity , the primary reason for the installation of a grounding leg being installed as part of your circuit(s) is for it to pick up stray current/arcs/sparks(ing) that do not find their way to the neutral or register as an overload within the general parameters of the typical operation of the circuit ; that can be a stray current which originated from the supply circuit or as with the case of lightning it could be of a point of origin from outside of the intended design (in which case we could be talking about an amount of energy far in excess of the capacity that your system is designed for) the grounding system is there to allow for/provide a means to at least aid in providing a point of discharge for that stray current and/or potential excessive overload , it's not intended to be a main active conductor during normal operation. One other thing that I think might be worth mentioning is that the general indication in the video was that "grounding rods" are not "good" conductors (or shouldn't expect to be good conductors) I tend to believe that there's a pretty considerable amount of variability that could exist in that area . A person could put a simple 1/2" or 5/8" ground rod down somewhere in dry soil which as he was indicating may not have a great capacity to conduct , or you may find as I see at times in my area that the electrical service is grounded to a steel well casing in an area where it may only be a few feet to the ground water table and who knows what the soil structure brings to the equation (sometimes this could be the circuit structure without a neutral going back to the incoming supply source ; NOT something I recommend) . But the point to try to address for the purpose of having a smooth functioning system with the basic safeguards being discussed is to incorporate the existence of a grounding pathway sufficient to provide an extra measure of protection from "adverse" system discharge(s) &/or excessive overload but not one which is going to interfere with normal , preferred flow of current through your circuitry. Different areas may tend to have different preferable methods for sizing and installing a grounding system for your area ; as was indicated in the video it's likely to be a good idea to consult with an electrician or inspector in your area if you need help getting it sorted out.
Nice Job with this explanation and use of Art 250.32 😊
Howdy. Yes.
In older systems where the riser/feeder uses the same wire for ground and neutral a soil electrode at the aux. building is absolutely mandatory. In a newer system with separate ground and neutral the electrode is not so important if the riser is very short, say 40 feet or less. Bonding of conductive parts is essential in the aux. though. But yes. The Code says there shall be an electrode.
If there is just a branch to the aux. to feed a few sockets, bonding of conductive parts is highly recommended. No matter if the branch is an old 2 wire or a newer 3 wire cable.
Regards.
For installing pool heater so i understand.
Main panel breaker = cut off panel = sub panel with gfi and ground wire to earthing rod = separate meter to measure power usage of heater = pool heat pump heater which case housing has its own separate ground wire to earth? Standard 220 volt wiring through out with boded main panel only.
I agree with Cesar! I would have Simply said treat it as a sub panel & with ground rod
For the longest time I always thought that the ground rod would take the load first as it is the closest circuit. However, as you have mentioned the connection to the transformer is the lowest impedance circuit there is so it actually takes that(with some very small current I suppose going to ground). THUS bonding neutral to ground is vital as it will also coincidentally trip the breaker on the way out. Amazing information!
Another excellent correct video! NEC indicates that you should NOT put ground rods on lighting poles. It came up in a Code class I took several years ago. The consulting engineer in the class got his mind blown when he found out he had been spewing them for years incorrectly.
I'm an apprentice so I was just the labor, but about 3 months ago we did exactly that. Rod in a lighting pole. Good to know. happen to know the section in the code?
Great tutorial, colors and your ability to simplify the code (black ink on white paper) is very helpful. We've read papers on ground current running back to the Utility company, via the neutral connection. Would be helpful if you were able to elaborate on that, and perhaps dispel myths or misconceptions about it.
Been working this issue for weeks since I discovered it with my shelter house. Unfortunately the feeder line from the house to there didn’t have a ground run to it (not to mention he didn’t bother running one from the service connect across the driveway to the main house). Electrician has already come out and it’s planned to all be redone starting the first). This ain’t cheap but I’ll feel better having it done right.
Just went through essentially the same thing. No ground in the undersized feeder to the metal shop building and no ground rod at the shop building or the house. Now it's been corrected with a new feeder install exactly like shown in the video along with changing out the fire hazard Federal Pacific house panel with a modern one. Agree it's not cheap at all but I'm happy with the work done.
Great response. I wired a greenhouse beside a main building last summer, here in Canada. The greenhouse was fed by two circuits from the main building panel, with a system ground wire from the main building which was not attached to the metal of the greenhouse. There is no disconnect at the greenhouse. It was located about 50 feet away from the ground rods for the home. Our electrical code is a little vague, so before I poured the concrete pad I laid in a ground plate, and I attached that to both the building and the feeder ground wire. To my surprise, the inspector required me to disconnect the grounding electrode from both the greenhouse frame and the ground wire from the home before he would pass it. His concern was something about stray currents between the two grounding electrodes causing issues.
that's because you only have branch circuits, not a true feeder with a panel. In many areas they might still ask that the building metal and slab rebar be bonded to each other, and then to a ground rod... but NOT tied to the electrical. (unless there's a panel)
If I recall, in the US you're only allowed one feeder to an outbuilding, with a few exceptions. They would want us to put in a subpanel at that point and then run out multiple circuits from there.
@@kevinmach730 ... in hindsight, those two circuits may be a run of 12/3, in which case a shared neutral would actually be 240 volts. IOW, qualify as a feeder rather than 2 separate branch circuits. Two conduits and two different breakers might slide, but I would be asking the local inspector if that would pass code.
@@rupe53 I considered something similar for my own outbuilding, but since it just didn't make sense to go through all that work to only have the power provided by 12awg wire. A few people reminded me the work is same more or less either way, if you have the space in your main panel, might as well opt for a small sub panel in case your needs change later. I am glad I listened, because I was able to add a 240v breaker for a heater and air conditioner.
Edit: Obviously, the wire was double the cost. and highway robbery at current prices. Plus I needed schedule 40 conduit, which you would get away without if you ran UF. But in my area, that requires digging down 2 feet as opposed to 17 inches.
@@kevinmach730 ... yes, it costs more, but in the long run you get MUCH more for a similar effort on the job. It's just a typical case of pay me now or pay me later to do it again.... so why bother with the shortcut.
A similar situation exists where the "external structure" is a well pump house. Usually the pump house is fed using only a single (often 240v) branch circuit, in which case the exception clause of 250.32 applies and a grounding electrode is _not_ required. But I've always errored on the side of caution in this situation and installed a separate grounding electrode. It only costs a few dollars more but I believe significantly increases the safety factor.
if new install I usually try install a sub panel in some well houses, pump on a separate 240V breaker, service outlet in case heating needed other use, and light on a separate circuit (4 slots) and a few install permanent 240V heating also so...
Amazing channel, love the highly detailed content! For the next video, could you please talk about separately derived systems (like stand-by generators), and whether they need ground rods or not, and whether their neutral needs to be bonded to the enclosure? Thanks.
I am a lineman and we put ground rods at every transformer and riser, so when my son built his detached garage with a panel I assumed he needed a ground rod , but the inspector (Ontario) said to disconnect it.
Thank you so much for you info and time. You will always be blessed like all good ppl.
Thanks again
I install signs for a living. We typically only install ground rods for signs that have electronic message boards. Mainly for “warranty” purposes but in actuality it’s for peace of mind on the boss’s end haha.
Thank you Mr. Stelzer. Thank you.
Like my steel out building (shop). Yes, Un-Bonded at the sub-panel. Its great with a metal building that has conduit.
Very nice explanation of ground and neutral to Sub panel. really good.
If you want to pass inspections; Yes. INspectors aren't always up on code.
this ground conductor will also help prevent differences on ground potential. have seen computer cable burned out by equipment with a 0.5v ground potential difference.
From what I've understood, once power has left the meter, the tie from neutral to ground should only occur once, which is at the main panel. Doing otherwise opens the risk of objectionable current. Earthing should happen to each sub panel, in most cases. If wiring enters another building without a panel--no further branches, then further grounding isn't necessary.
Hmm In australia it’s kinda similar. We have MEN link earth and neutral at the main switchboard. The earth should be sized to the mains capacity. You do not install multiple earthing systems you can only have one at the origin
Mike holt did the nutty thing hooking up 120v to a 10 ft and 20 ft rod. Not enough to trip small breaker.
Ground faults don’t go to earth. Faults go back to the source.
question: Metal industrial building. 480v 3 wire delta service therefore no neutral coming into building. The 240v transformer has the neutral and grounding conductor bonded to to the metal building. Is a ground rod also required? Awesome channel for a non electrician!!
Does the building have to be a certain amount of feet away for this to apply
Great information! Can you clarify this? What if an out building has a sub panel feeding another smaller sub panel in the same out building, would both sub panels require their own grounding rods? Would only the sub panel connected to the main be the only panel needing a ground rod? It is my understanding that only if the sub panel resides in the same building as the main will it not be required to have its own grounding rod. What is correct?
A few years ago I ran a 100A sub panel from my house’s main panel out to my shed. It was fully permitted work and inspected by the local city inspector. I’m glad he had never watched this video because there was definitely never any discussion of installing a grounding rod! Now I guess I won’t sleep well until I go install one. 🤦🏻♂️🙄😂
Actually, I think you need to install (2) rods.
Speaking as an EE, you can't have too many grounding electrodes. If there's *any* question, put in another ground rod. You want that green conductor to be as close to earth potential as possible, which is why it's not bonded to neutral anywhere other than the main panel. Neutral wires carry current, wires have resistance, and current through a resistance has voltage.
The part about not using the earth as the grounding conductor reminded me of what I used to do as a teen when I wanted to go fishing. (Don't try this at home.) I'd water a bit of the yard, push a steel rod about a foot or two into the ground, and connect that rod to 120V. In a few minutes, the worms within about 5 feet of the rod would be wriggling on the surface, where I would just pick them up.
👀 Hmmmm sounds like a good idea though 🤔🤣
What creative teen the fished didn't try that at lest once.
./Sigh
Why would you not want the most efficient path back to the source?
In this application it seems excessive grounding electrodes will prohibit the ground fault from being detected and opening the circuit, increasing the risk of being shocked.
What happens if you stood on that ground...barefoot?
Dustin should be required Viewing for every Apprentice, excellent info!!!
Thanks Dustin, great info.
There has to be a reason that each building needs a ground rod. What bad stuff can happen if the secondary building subpanel is treated like a subpanel within the main building, no ground rod and bonded ground + neutral?
Hello dustin my elec instructor, can you do a full video on panel branch cct balancing ,what appliances and rooms you would put on the L1 (A)and L2 (B) phase in a single phase domestic system for the lowest neutral current.
I try to think about it in terms of a fault at a device needs to trip the upstream breaker. It clarifies the thought process in grounding
Hey! I'm in florida, and wanted to run this by you, because I have had this argument online before. This is in the case of a Solar system, that is fed by a line-side tap, and not a breaker. Engineering, as well as inspectors, require a lineside tap from the main service panel (bonded) to feed a fused disconnect, which is also bonded.
I see it as a "seperate" 1st means of disconnect, due to the inspectors and engineering. We are using pierce taps on the service lines on the line side of a main service panel, so upstream of the main disconnect. So we are branching unfused lines from the meter, creating a secondary system.
Sorry for rambling, but in this case, we always and must bond our neutral and ground in the fused disco, and keep the MSP bonded as well.
I see electricians arguing that you cannot have 2 1st means of disconnect, and that only the msp should be bonded. What is your take? I only equipment ground a disconnect (non-fused) when I'm feeding from a breaker.
BTW, I Love your page, been watching for years! I've been a solar installer, working under our electrician's lisence for 5 years, and am soon going to apply as an apprentice and work towards my journeyman's. I have upgraded service panels, changed out outlets, installed switches, lights, sub panels, ATS's, even meters and meter mains, all along with our solar and storage systems. I can't wait, and believe the years of watching your videos has a lot to do with why I am where I am today. Not a part of your discord or your advancement classes but believe I will be joining as soon as I officially make the switch! Thanks bro!
Ugh. Just rewatched the portion where you're talking about multiple buildings and then wind and solar and realized you said that those are all separately derived systems. Which is exactly what my comment said in 100× words. I've always been confident that I was understanding it correct, just see ppl argue it wrong sometimes on electrician pages. Lineside tap to disco, disco must be fused and neutral must be bonded to ground.
If you read all this... I'm surprised, and thanks! Lol
Question. We have a house built in 1956 with no grounding wires, no ground bar, no ground to the foundation rebar, etc. The service entrance is to a meter, then to a main panel with a 100 amp breaker then to a panel in the house with another 100 amp breaker then to two in-house subpanels which connect to the circuits. Nowhere do I see the neutral bonded to any of the panels which makes sense since there are no grounds. We have another subpanel at our wooden shed which is connected to the main panel through a 40 amp breaker to #8 in the subpanel with its circuits protected by a 30 and 15 amp breaker. It also has a grounding system i.e. a ground buss connected to the subpanel and to a ground bar with #8 wire. An electrician friend suggested I connect the neutral and ground busses in the shed subpanel. I am not sure that is a good idea. Comments?
Wow...I need to fix my metal building, LOL. I had a 100A sub-panel/distribution panel on a pole with L1/L2/N/G from the main in the house. I added a metal building (34x28) on a slap next the panel and actually moved the panel inside my structure. everything is as you show in 250.32(b) but I do not have a grounding rod at the metal building and my ground (green) is not connected to the metal building just to the ground strip in the sub-panel.
Can 2 structures, if they are close enough, share a pair of grounding rods?
awesome explanation. simple and to the point. thank you.
HELP!
I have a sub panel in my garage (fuses 🤦♂️) that I'm replacing. I have to run new feeder with an egc. The existing buried pvc conduit contains feeder hots and neutral (only 10ga with no egc 🤦♂️), travelers for a 3-way light switch back at the house, and a phone line 🤦♂️. I'll be replacing the 3-way with a smart switch and deleting the phone line.
The problem I have is that the sub panel is in the middle of the garage slab with no grounding electrode. Will I have to drill the concrete and pound a 20' electrode? The closest exposed earth to the panel is over 15' away. There IS a buried copper water line to the garage, within 3' of the sub panel.
Love your content! Keep it up.
Dustin, I love you, man, and I appreciate the videos. I just wish you were in the common section a little more, answering questions and such.
Great video do I have to ground a barn building if there is no electric service in the building?
I guess my questions is, in a detached garage or any building, if I install an MLO panel with no main breaker, do the ground rods for that building attach to the mlo or back at the service disconnect at the other building
If you have existing outbuilding serviced by a three wire feeder (two hots and a neutral) with no equipment grounding conductor and the outbuilding doesn’t have any metal connecting it to the main building with the service, is it correct that you need a grounding rod at the outbuilding and you bond the ground and neutral at the outbuilding subpanel? Adding an equipment ground conductor between the two would require trenching through an existing driveway so wouldn’t be easy.
Great video! Where can I find requirements for this disconnect in the NEC?
I would say grnd rod @ poles is for secondary lightning protection
Thanks for sharing your knowledge.
I'd love to see a video of you actually wiring the subpanel. As you explained, the neutral does NOT tie to the ground inside the subpanel the way it would in the main house. If I look at the panel inside my house, both bare (ground) and white (neutral) wires can be attached to the same locations in the panel, and those are all attached to the panel itself.
If I understand what you've said, that's different in a subpanel. The grounds will be tied together and grounded to the panel, but the neutral wires will NOT.
Do subpanels thus come with one set of lugs for the bare ground / green and a different set of lugs for the neutral / white?
When you purchase a breaker panel to use in an out building as a sub Panel.... most often you have to buy with the panel, and extra grounding Bar, for that brand of panel. Some brands come with them, but most do not. It should come with screws and the panel should have a place to attach it. Must use the screws that comes with the grounding bar. This will be your "Grounding" (Green Wire) connection for all equipment grounds. The Neutral Bar already in the panel is your "Grounded" / Neutral Bar, for all of your neutral wires, (white). Remove the Green ground screw from the Neutral Bar, or jumper, which ever it has. You don't need them. The Grounding Bar you install will be Bonded to the Breaker panel "can" using the screws that come with it.
Great info, I think it answers my question but I have a specific scenario and I'd like your response. I'm connecting my "shop" (a prefab shed) to a 50Amp RV outlet. From my main service panel I've wired a 50A 240v outlet, then run a 100' Southwire 50A extension cord (6/3+8/1 ground) to a Reliance 50A inlet box, which can then be wired directly to a sub panel. (No transfer switch, no generator, I'm permanently powering the shed via the extension cord from the outlet.) The "sub" panel is actually a Square D 100 A Main Breaker Panel so I have my main disconnect. There is no ground bus bar on that panel. I assume I have to attach one separately, and hook up the equipment ground wire from the inlet box to it. So the main question is: do I need to stick an electrode in the ground and then connect that to a ground bus bar, or can I just attach the 8/1 grounding wire from the main panel to the ground busbar on the sub panel and call it good? Your video seems to say I need to do both: add a ground bus bar to the sub panel, then drive an electrode into the ground and tie it to that bus bar, then connect the equipment ground from the feeder wire as well. But this seems like multiple paths to ground, unless I'm totally muddled. Thanks!
Great video. I'm in southern Missouri and there are basically no inspections here, except for a few municipalities. I see URD for feeders a lot, with no EGC. They just drive a rod. I fix a good number of these.
What sort of issues do they have when setup that way that you are asked to fix them?
@@kevinmach730 no issues to speak of, unless you have a ground fault. I normally get called to fix hack work, and I'm thorough.
In southern MO are boat docks treated as separate buildings? Boat dock electrocution is a legit problem..
I'm new. What's URD?
@@toddkerkhoff4672 Missouri has no statewide inspections, and very few boat docks 😁
@Electrician U have you used the Combo #1, #2 bits before and what do you think of them, they are found in the Klein 32305 Tool. Also same for the The Klein ET310 what are your thoughts on those?
Do you have a video about how to install a service discount after the meter? Upgrading our electrical. House now has a main and a sub panel. Want to know how to bond and ground.
I love this teacher!
What is required where a three wire USE triplex is run from the house to free standing frame structures without a seperate grounging conductor as in an older system? Do you have seperate grounding rods for each out building and do you bond wirh neutral in them?
When is your sub panel required to have a disconnect or a main breaker for a separate building?
I had an inspector tell me that only one continuous wire can be run for the ground rods; it must pass thru the first and terminate on the second rod. You cannot have 2 separate wires, one going to each rod. Is that a local thing? Also: 6' is the minimum space between ground rods, is there a maximum distance? If two panels are located relatively close to each other, can they share the same 2 ground rods or do they need their own? Conversely, if you had 4 ground rods, 2 ea. for main and sub panels, would it be better to directly connect them all together? If you have a ground wire directly fixed to a water pipe, can you attach a ground rod to the other end of that pipe, or does that rod require a direct wire to the panel? I know these questions may seem obvious, but codes are not always so obvious. Thanks for your shows!
By tying the neutral and ground together in those other buildings, you’ll probably end up with some strange goings on that will affect micro electronic equipment; such as musical equipment, sound and lighting equipment, computer equipment.
yep, parallel paths are no bueno
My welder acts up in my detached garage and I wonder if this could be the culprit. It has a sub panel and I'm wondering if the neutral and ground bars are bonded. The welder welds fine for about ten minutes and then starts sputtering and becomes useless. It is not hitting the duty cycle limit, as I have tried two different welders and they both have the same issue.
where do I put the stripper pole and disco ball in my separate building?
Thanks for the great video, this came up on a job site just this week (in Washington state.)
Is there a reason why you drew a disconnect on the outside of the accessory building fed by the feeders? I'm reading 225.32 saying the disconnecting means can be installed inside or outside the building being served. Appreciate your insight!
Hi thanks for your video. Do I need to install a separate ground electrode for my solar panels on the dc side and another on the Ac side?
What about on a 400 amp service? Installed disconnect at the meter and ran conduit out to a barn with its own 200 amp panel. Can I ground the disconnect at the first set of ground rods or do I need to drive 2 more ground rods out at the barn?
Hey love the content I work in the solar industry and something I've been instructed to do has been confusing me a bit. I've been told in the past the reason we do this is due to some inspector somewhere in Florida. We do interconnections with generator systems and tap the line side of ATS's to feed disconnects for our sub panels. I've been told that when we do this the PV system becomes a service and that we're supposed to run a ground rod and bond our grounds/neutrals in the disconnect. (Which is fused). Is that correct? The other electricians I ask never really give me a solid explanation. I've always been under the impression that the EGC should be bonded to the ATS and the grounds and neutral separated. Just because the transfer from utility to generator doesn't mean that the PV suddenly becomes a service.
Thanks Justin
Have a question about grandfathered systems. Come across a lot of sub panels with only 1 conductor used for neutral and no ground. Should those have a ground rod installed as well? Inspectors call this one out a lot in my area.
I noticed there is some electrical work that was done to my house unpermitted years ago before I bought it. Specifically a 240V outlet and a electrical panel inside my outbuilding. I was wondering if the fact that these were not permitted May post problems if I were to sell the house one day?
How do you know this was unpermitted?
depends, in my area no permit needed for doing yourself, unless a major remodel but usually just building permit then all aspects are inspected, but working only adding a outlet or other simple things no permit needed so check with local AJC if permits are needed for simple electrical if doing yourself if allowed.
Outstanding explanation
Thanks 🙏for sharing, even though I live in the UK physics is always physics. Do you have a video on separately derived systems perhaps?
I built a solar shed which can provide power and/or be provided from the main building where the Victron inverter is supposed to lift the neutral to ground when connected to the mains. However I don't feel safe non having the two ground electrodes bonded together so I have arranged for an automatic contractor for phase, neutral and ground change over so to keep the two systems totally independent. However if the inverter is used for charging as well as assisting the all system would run on the main building earth bonded to the neutral at the service and I would still have the secondary grounding electrode connected to the PV system. Should I just bond the two grounding rods and not worry about it or have I done the right think by keeping the two systems grounds independent from each other?🤔
Can you do a video explaining how to wire up a RV/travel trailer with shore power (120v) to a panel in the RV? When to bond the ground and neutral, at the rv panel or is that considered a branch panel and you consider the pedestal the bonded panel?
It would be a sub-panel. The neutral and ground must not be bonded in that, otherwise current flowing in the neutral will be split between it and the grounding conductor, so there will be some potential on "grounded" metal cases.
Awesomeness!!! Great code book Information!! Keep them coming lol!!!
In one of your videos you were talking about old breaker boxes. What was the name of the place that may have old breakers?
So if I have a sub panel in my garage out back I need a disconnect before the sub panel?
What if you have this same scenario except your sub panel has a main breaker instead of a separate disconnect. The feed from the house feeds the main breaker.. would you connect your ground rod and the equipment grounding conductor on the ground bar in the sub panel?
This is interesting
I built a garage that became my main service drop location (i moved the service meter and drop to the garage) making my house a subpanel of my garage via a 100amp feeder.
My electrical inspector made me disconnect my original grounding electrode conductor. His reason was there should only be one ground at the source (service). Ie i have aabandoned rods at the house and a working ones at the garage (new service drop)
Was this incorrect?
I'm amazed at the contradictory information online regarding RV pedestals requiring ground rod or not. Has this been clarified in the code or is there still an argument over whether the pedestals are structures or equipment. I see grounding rods at RV park pedestals all the time, but it seems by your excellent explanations that this does not add touch protection, etc, but rather only lighting protection of equipment? Some online information even argues that grounding rods at the pedestals down stream of the grounding rod at the source panel will fail inspection. So confused.
Very clear the answer thanks
Is a disconnect code on the 2nd building if you have a breaker in the 1st building rated for the sub Pannell
can i use 5/8 copper rod to tie to footing rebar on my 24x30 wood shop?
What makes, or should I say... what causes a grounding electrode to smoke? Have you ever seen that happen? I came upon a house for a service call where the customer says the ground is arcing, popping, and smoking around the grounding electrode. When I arrived, the grounding electrode is about a foot over from a 3/4" rigid conduit that goes to his hot tub, and the underground feed to the subpanel inside the garage is about a foot to the left of that as well. He said he turned off the breaker in the house main breaker (100A) that feeds the subpanel in the garage. Yet is was still smoking when I arrived. The grounding electrode conductor is attached to an equipment grounding lug at the left bottom corner inside the subpanel cabinet. It was not evident that it existed from outside. There was some recent remodeling going on, so everything was finished (walls, etc). When I opened the cover and saw a black wire in the lug, I took a meter out, thinking someone hooked a hot wire up to the cabinet lug??? Didn't make sense. After careful examination I find it was attached to the grounding electrode. The area around the grounding electrode was still smoking....even with the power off that fed the subpanel, so I removed the wire rom the lug (No voltage on the wire, by the way) taped it up and the smoking stopped. Can you explain that one?? I have to say, in my 42 years of being an Electrician with industrial, commercial, and residential experience.... I don't remember ever seeing something like this, and I thought I have seen it all! God, I love being an Electrician!!! It never gets boring, and I can't get enough of it. I didn't even charge the guy for that service call.... I must have chalked it up to a new learning experience.
I see on your diagram that the ground rod conductor is connected to the disconnect and not the subpanel? Does it matter which or can it be either or does it have to be both?
I am considering updating wiring for my garage, currently its fed by two hots and a neutral, No ground. Can I replace the fuse box with a breaker box and add grounding rods at the garage without tying it the main house system and still comply with code somehow? From a non-code safety stand point would it increase safety to add a ground at the garage or is there a hazard I am missing?
great video!!!!......have you done one on 10K-65K AIC beakers? and why the difference, and whats inna breaker?
I'm still confused. I understand the sub panel in the remote building needs a ground rod, but do I need a separate ground rod for the disconnect on the pole outside the building?
I TAUGHT JUSTIN ALL HE KNOWS.
Very nice breakdown, I really love your knowledge share!!
As far your drawing, Can’t you just eliminate your disconnect and go straight to your panel?
IANAE, but I would think there has to be some kind of disconnect, whether a separate switch or a main breaker in the top of the sub panel. Interesting question, looking forward to seeing a better answer.