Sub Panels Explained - Why are neutral and ground separated?
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- Опубликовано: 9 май 2024
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How do sub panels work, how are sub panels wired, why are neutral and ground separated, what happens during a ground fault, what happens when we lose a neutral wire, what happens if the sub panels is incorrectly wired. All this and so much more covered in this video.
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Good video. Can you do one on UK electrical systems? TNCS
Kindly make a detailed video on the Electronic Speed Controller and Servo tester controlling the BLDC 2212 Motor.
What about your videos are Copyrighted or free??
Copyrighted
Can u guys do a video on comparator 🙏
As an electrician of 36 years I enjoy your videos very much as it reminds me of why we do what we do everyday without thought. It helps to refresh my memory thank you!
Help me out here, main and sub panels connected by non-metallic raceway and way too far apart to ever be jointly touched. I'm not following how an absent neutral fault in a (wrongly) bonded sub panel is somehow worse than an absent neutral fault in a main panel with a (properly) unbonded sub panel. It seems in both cases current returns to the buried ground rod of the panel in which the absent neutral fault exists, energizing that panel's housing, and perhaps not tripping the breaker.
So is it just the issue with current getting on a metallic raceway between the panels or an alternate path between the panels via a person contacting both that is not present with my scenario.
@@melainewhite6409 Because when you don’t isolate the neutral buss in a sub panel regardless of the distance the ground buss and the neutral buss are bonded together through the panel frame. Now the ground buss and the neutral buss become one through the metal frame of the panel. This is dangerous because both busses are going to carry current back to source (Which is your main panel, then your utility). The ground buss should NEVER carry current unless you have a fault to ground which then it will cause the circuit breaker to trip. In the main panel it is not an issue because the only thing between the main panel and the outside pole is your neutral/ground where they now join as one conductor. 😎
@@Mark-eu4di Thanks
I'm not a pro, but I'll never forget a quote that I read on Tom Henry's website nearly two decades ago:
_"An electrician is educated to the fact that there are times when we _*_don't_*_ want electricity to work."_
@@CensoredByRUclips.You get my thumb’s up for that! I just copied that quote into my iPhone. Priceless. I am 68 and also no pro, but I did my first electrical work - everything, including a full SEP replacement - on my first house nearly 45 years ago. And it’s still standing. Cost me $37,500, and it’s worth $700,000 today.
I have been doing this for 20+ years and "just knew" what do do and why. This explained it so much better than anyone has in my 20 year service.
Same
Excellent! The details and explanations of US Home wiring in a concise 16 minute video are quite an achievement. The illustrations, animations and well paced narration essentially make this equivalent to a thick textbook and many hours of lectures in a classroom setting. Additional kudos for the on screen reference foot notes to to the Electric Code and the bonus GFCI explanation at the end! Thank you for these great videos.
Glad you enjoyed. The NEC codes were added in for extra info as the last electrical panel video descended into a war zone in the comments section, this should clarify things
Yes good job, very clear now. @@EngineeringMindset
Funny that we seem to learn better from video yet classrooms are still book centric. If we had a movie a couple times during the school year when I went to school it was a miracle. Maybe 3 or 4 a year. Maybe the classroom of the future is RUclips. We just need to organize the content.
@@cityguyusa Yes I agree!! A video is worth a thousand books lol😊
@@w1swh1but the video keeps referring to the books, so..... I'm confused now!
This is absolutely the best presentation I have ever seen concerning this subject. I have been in the power business for over 40 years and my personal observation is that most people in this business, including myself, are hard pressed to really explain this adequately or have a true understanding of the "why" of this very important subject. Really great job. Thanks
The diagrams at 1:44 and at 11:04 really help to make things clear.
I know it takes a great deal of effort and attention to detail to explain something in a simple way. The more you try to explain something simply, the more illustrations and flow you need to construct, in order to get across the information without leaving your audience feel like they've already lost you. You have done exactly that - put all your knowledge together without a ton of effort to transfer that to your audience in a short manner. In the field of electrical engineering, not a lot of channels or content creators do that, like we see in the field of computers and IT/programming. You are one of those few content creators who is also hands-on and detailed, and we see your level of effort and really, really appreciate you!
We do not bond sub panels because a ground cannot be a current carrying conductor. If you were to lose the neutral in a sub panel, and it was bonded, everything would work through the ground. And as I just mentioned the ground can not be a current carrying conductor. Thank you.
Thanks for putting it simply
Should your ground wires be run to separate bars in the box?
As in the ground being separate from the neutral?
@@user-vb4em4vm5hyes you should add a ground bar to your sub panel and keep the grounds in neutral separate not put the ground in neutrals together on 1 bar
Correct
Always wanted to understand why you don't bond ground and neutral in a sub panel. Thanks for the great content!
Glad to help!
I still don't understand. Cau you explain please 🙏 to me? Thanks...
@@spotscorner6040 I really appreciate you kindness for answering. I do understand that the ground wire needs to be bonded to the white (neutral) wire in the box panel. What fo not understand is why the su panel is not. Thanks....
Because the ground cannot be a current carrying conductor, and if you were to lose the neutral in a sub panel, everything would still work through the ground. And like I just said the ground cannot be a current carrying conductor, so that is why we do not bond sub panels.
@@williamrose7818 that explanation was the missing piece for me. Thank you!
You have the best explanations on the platform. Please keep doing what you do!
After years of asking why you don't bond neutral and ground anywhere outside the main panel and getting the response "because you just don't", I finally understand why. It's all about getting the breaker to trip when it needs to. I can also see why other countries requires GFCI breakers, as you're SOL if you lose service neutral in the majority of US homes. Thanks for making this extremely easy to understand!
This is I will say the best video I've seen explaining sub panel wiring and faults that could occur if miswired. Good job!
This is the best explanation I have ever seen on the installation of sub panels and grounding and I have done electrical work for over 50 years.
Thank you for this, very informative. 22 ish years ago when I was a wee young apprentice plumber, I was cutting in an ice maker tee off the main and got whacked off my ladder. I found out latter that they 'lost the neutral'. I was so unsure about what actually happened, that for many years after, I would use jumper cables to jump any main cuts. To this day I keep an ncv wiggy in my tool bag for the occasional 'shocking shower valve'. Thank you again for this great presentation.
Excellent video. Properly explained and I appreciate the correct terminology. I’m an electrician in Canada and we do it the same. The only difference where I am is a grounding electrode is not required for a sub panel if your bonding conductor is sized correctly. Of coarse you always have to check with your local municipality for amendments and technical interpretations to the national code. Every area is different due to things like climate and weather.
Nicely done mate! I wish you could have included some "in-the-field" multi-meter readings of this going wrong in the wild on bad installations. Great job Mr Mindset
This has been explained to me 3-4 times and this is the first time I’ve understood it. Thank you!
Finally. A clear and coherent explanation delivered in a way that even I can understand it!
Finally somebody has a proper video with no crazy loud music dancing clowns shaky cameras or weird stuff going on. Just excellent illustration perfect explanation and detailed video work thank you so much I just subscribed❤❤❤
There are a lot of great electrical basics videos on YT, but by far, you've explained these concepts so well, and along with the fantastic graphics, made these concepts very well articulated. Thank you for producing these amazing videos and keep up the good work!!
Excellence in presentation in all aspects, learning isn’t any easier than this!
Nicely done. Many people don’t understand the ground/ neutral scenerios and you explained it very well.
Thank you
The best and most illustrative explanation I have seen!. Wow! The detail, the graphics, the NEC references, the accent! Great video.
11:48 this is a ground fault and short circuit. Another possible ground fault is neutral to ground, which is not a short circuit and won't generally trip the overcurrent device. Just another reason why GFCI is important!
This is by far the best explanation I have ever seen. Great job
As an American, thank you very much, clearly British Engineering Mindset engineer, for explaining North American residential electricity. I appreciate it continuously as your accent's clear timbre narrates.
Thanks for this video! I need to revisit the 110 "Shore" service panel in my bus conversion motorhome. The "Main" panels in RVs are technically sub panels and I need to make sure mine is right. I knew this when I wired it and knew about the special considerations for the neutral and ground bus bars, but I didn't know _why._ Now that I do, it all makes sense.
Very helpful video, and the segue into your sponsor's ad starting around 7:35 was about as smooth a placement as I've ever seen :)
Excellent video,man.Thanks for your time.Looking forward to the next one.. You did a phenomenal job explaining trunk/branch electrical. Cheers! .
This video is so incredibly clear and the animations do a great job of further describing the dialog. Excellent resource, thank you for creating!
Fantastic breakdown! I really you appreciate citing the NEC so I could follow along. I understand grounding and bonding but know I feel that I can explain it. Thank you.
Easily the single BEST video I have EVER seen on this subject! Really, really well done!
Wow, what a great video. I have read through dozens of explanations of setting up panels and have felt like I was getting conflicting explanations. Your video put it all together and it now makes complete sense. Thank you!
omg this is a gold level video on this topic. there are few things i couldn't get but i'll watch again to try to understand them. Thank you very much for this much detailed and easy to understand step by step telling
These videos are an amazing training resource. I would love to see similar ones for European standars!
In Florida where I live, the grounding electrode conductor is bonded to neutral in the meter can rather than the Neutral/Ground bus bars in the main panel.
Thanks! the visualization with the audio commentary really helped me understand this a lot more.
EXCELLENT VIDEO! 👍👍I knew that sub-panels should never be bonded because a fault could cause all metal parts to become electrified. But I didn't know exactly WHY.
After I watch this video a DOZEN more times, maybe I will finally understand how it REALLY works...
It's been a huge delight and learning experience being subbed .... one of the few channels I ring the bell for notifications .... Hope 2023 has been a perfect year for you and those you love.
I am just a DYI dude. OK, I'm an engineer and fairly well educated about electricity, but I'm no electrician. I've rewired my house, replacing old wires and balancing circuits (with guidance from a licensed an electrician), installed new circuits, etc.
I've never understood why sub-panel ground and neutral are not bonded. I've watched a number of RUclips videos and asked pros, and they just never really made sense to me. This video has made it very clear, and it was done really well. Thank you!
Thanks for this simple and straightforward explanation. Now, I use a portable sub-panel which I use to run my VFD, welders and portable lights. Should the wiring be as if it was wall mounted?
Transformers almost always connect to 2 of the 3 phases of primary, other than that this is one of the best and most accurately explained videos I've seen.
Is that not how it is always done, I think the video is definitely wrong with regard to the SERVICE HIGH VOLTAGE LINE CONNECTION. Don’t you need to have the high side of the transformer connected BETWEEN two phases so that ALL of the current loops through them and not a transformer ground. Some rural high voltage lines have two lines and not three but I don’t think that one is a neutral but just the other phase!
There are a number of ways the transformer might be connected. It's going to vary by region. The one show is the simplest version just a single phase pole mounted type, it will work just fine. This isn't the point of the video so I have not discussed two and three phase connection transformers, just a basic understanding of how it's all connected to the grid so we understand the fault paths.
@@EngineeringMindset I was going based off your statement that it typically only connects to one phase. That is incorrect. Although single phase connecting transformers do exist, they aren’t typical. They are the rarest type. They typically connect to 2-3 phases, even for residential.
A single phase delta transformer has two bushings connected to two of the three primary wires, so the primary winding sees the phase-to-phase voltage. This avoids returning primary current through a neutral that must be solidly grounded to keep its voltage near earth potential. Since the neutral is also provided to customers, this is a big safety advantage in a dry area like California where soil conductivity is low. The main disadvantage is higher cost, e.g., from needing at least two insulated 'hot' phase wires even on a branch circuit.
Other areas that have ground conductivity that is higher can be wired as per video but require a neural return path to the substation. This appears to require a 4 wire system on the primary side (or 2 wire system on 1 phase system) unless the video author suggests that the return current from the line transformer to substation can travel through the “actual ground”! So it is suggested that the provided video diagram is the simplest or a 4 wire system is simpler than a 3 wire primary system. Not too sure that a 4 wire system makes more sense than a 3 wire primary system particularly from an educational perspective. If the suggestion is that the return current can flow through the actual physical ground then that brings up some other safety concerns.
The only high voltage distribution system system that I am aware of that has current flowing through the actual physical ground is in HVDC long distance transmission lines.
So maybe the youtube author could do a video on the “economic considerations” of why a 4 wire system is preferred over a 3 wire primary system.
@@phenry5083
At least what I have seen in California it is typical to connect the primary between 2 phases for a residential “split-phase” service.
The other possibility that I have seen in PGE areas is the use of multiple pole transformers feeding a 240v split-phase circuit that is placed below the high voltage lines. This is done to provide redundancy to the lower voltage service circuit but I have seen this cause significant low voltage problems if one of the transformers is nonfunctional.
Wow! The detail, the graphics, the NEC references, the accent! Great video
The greatest video to explain the basics in one place. Great work. 😊😊😊😊
As an individual learning with minimal (non existent) guidance from the company I work for. Thank you sir for your concise explanation.
This was an excellent explanation of the subject. This is the most detailed and understandable presentation on U.S. electrical systems I have come across.
Thank you man... This is the best-explained answer to this question I've ever found since this question began plaguing my mind.
Very good video, and as an electrician myself I appreciate the NEC code references. A couple of things.
1) At time 13:00 where you talk about "double bonded ground fault condition", NEC reference 250.6 talks about "objectionable current" which is essentially what you're explaining when the installer mistakenly bonds the neutral and grounds in both the main and sub panels. It would be helpful to add that reference.
2) At time 10:50, you're code reference is incorrect. Im assuming this was just a typo on your end. You meant to reference 250.24(A)(5) which prohibits the grounded (neutral) conductor to be bonded to the equipment grounding conductor(s).
But awesome video. Thank you for making it.
Thank you. Good points too. For the NEC codes I have just written the article number and the section number rather than the sub points within that section simply because I think it's important the viewer reads that entire section and not just the sub point else they will miss vital information.
Yes that makes sense, and I do agree it's more important the audience doesn't get lost in the weeds. Whenever I have to explain electrical concepts to my customers I try to keep my explanation simple and easy to understand.
This video explains the question I've had for a long time, thank you so much for explaining that. I still have a couple questions but I now understand the reason ground and neutral are connected is to trip the breaker. I can't help but think that there has to be a better way but can't comment on that at the moment. I'll rewatch and think on it a bit more before I ask any other questions.
The neutral-to-ground bond really belongs in the transformer, rather than in the disconnect or panelboard. But, due to the fact that most service transformers are utility-owned, rather than customer-owned, the NEC makes a compromise to require it in the service disconnect instead, since it's the first piece of equipment that the customer controls. This becomes a big problem when there are service disconnects (plural) which the NEC allows, as it forces you to undermine the entire purpose of restricting this bond to one location, and requires you to do it in all of the service disconnects.
It's also very common that multiple customers share a transformer, which ends up requiring redundant neutral-to-ground bonds.
A much better solution would be for the NEC to only require it in the dominant service disconnect, when there are service disconnects (plural), and base its sizing on the sum of the service disconnects. Then, all smaller service disconnects would be built as subpanels with separate grounds and neutrals. And if there are customer-owned transformers, put it in the transformer instead of the secondary disconnect.
The explanation + animation really helps! Thank you!
Very well explained. Along with problem situations explained.
I really loved you video and how you broke everything down into simple terms. I Just wanted to let you know though. At lease in my area, the power companies and inspectors require the grounded wire coming from the grounding electrode to go straight the the primary connections in the meter located in the sealed power company compartment in the case of a meter disconnect or meter panel combo. not to the electrical panels shown on multiple occasions in your video. Sorry to bring this up but it is an important distinction. Hope this helps. I know it will definitely help someone pass inspection if they are installing a new service or repairing an existing service.
Literally it was this video that provided the lightbulb moment I needed to finish my solar installation. Thanks g!
Glad I could help!
This is a very clear and thorough explanation of this question. Well done!
Exception! I am going to go out on a limb and say there is one exception to the rule - you should bond the neutral and ground in a subpanel where there is a gounding system at the subpanel and there is none at the main panel.
While I know much if not all of this from watching so so many other videos and studying on my own, this ONE video explains everything so so so so well.. Amazingly well done. The flow of electricity with the dotted lines is critical in helping people understand how this all works. SO much great info in one single place. WOW!
Excellent explanation, I,wired a sub panel for a solar system to run some of the circuits like, well, sewer lift station, refrigerators and a few outlets for back up and had a hard time finding the answer to my questions, this video did it with ease.
Seen our new video on HOW SOLAR PANELS WORK in detail ruclips.net/video/Yxt72aDjFgY/видео.html
The best and most illustrative explanation I have seen!
You did a phenomenal job explaining trunk/branch electrical. Cheers! 🍻
Glad you enjoyed it!
A great explanation that I have shared with my son who is new home owner as he tries to understand basic electricity.
Impressive video Paul!!! What an effort and excellent job explaining so much. Could you explain to me the dual termination neutral/ ground bar. In Canada, I understand the US and Canada to be very similar code. But if I connected the ground wires to the neutral bar in a main panel that would be a 100% fail even though electrically they are the same point in the main panel. Is this common practice in the US. Also all the panels we get in Canada which I assume the US gets aswell, Square D, Homeline, Seimens, Cutler & Hammer, etc have ground bars provided in the metal enclosure specifically for bonding. And ofcourse isolated neutral bars installed for neutral connections. Obviously it's not allowed to connect the neutral to the ground bar, but neither is a bonding conductor to the neutral even tho they are the same point electrically due to the green bonding screw or tab from the neutral bar to the enclosure.
You had this in your last video as well.
Thanks
It's a great explanation to this topic. The best one i have seen. I wish i had seen it early then I would have saved some money on installing a sub panel by myself. We ended up hiring one electrician for 1K.
The best explanation of house wiring ever.
Hello,
Been enjoying your channel for years, thanks for everything.
Video topic suggestion: MRI cooling. Using liquid helium at -452F to cool giant magnet flying around someone’s head is pretty sweet. Would love a video about all the components of the cooling system! Thanks!
Brilliant video sirr..long awaited.. beautifully and thoroughly explained 😊🎉.. though couldnt grasp somethings ..will again surely go through that
Phenomenal video! Have done a bit of electrical work with my father on our Farm in the past and now do a little here and there and this video succinctly gives a great overview of concepts important for working knowledge!
This presentation is well graphically put together. My take away is to know what you are doing. 🎉
Amazing! This is the best explanation with animations that I have ever seen. Not only that, you provided the perfect explanation of why an EGC (proper bonding) is required and also how a grounding electrode by itself is not adequate! Additionally the explanation for the GFCI was great! Thank you very much for making this video.
Glad you liked it!
You definitely explained it. However a wiring schematic would be much easier to understand. The pictures can be used to layout the components but when it comes to the scenarios, use a wiring schematic which makes things crystal clear.
Just OUTSTANDING! What an incredible resource. Thank you!
BEST explanation I have ever seen or heard. Bar none!!!! Well done Sir.
@12:57 When bonding the subpanel, it is true that parallel paths occur during ground fault but its not a big deal since it is shorted and therefore will happen only momentarily. The real problem is during a normal condition. The current will still flow in the two paths and also through the enclosure.
Yes, I agree what he said was incorrect and that the breaker would do its job. After I posted my comment I scrolled through the comments to see if anybody caught it.
This was super helpful, thanks for your awesome video!
Hi bud
Love your videos, very educational
I was just wondering if you could do a few videos on electric vehicles? How they work, earthing systems and protective devices etc?
Love the video, but also discuss objectional current on the metal parts under normal operation when sub panels are bonded accidentally
Excellent video,man.Thanks for your time.Looking forward to the next one.
Am going to watch this video over and over until I understand every scenario. Thanks TEM
Spot on !!!
Licensed master electrician of 40 years in NY
Thanx for excellent vids....
Great video. You are so clear in your explanation. The best illustrations I've seen. I will definitely be watching more.
12:58 - 13:47
I need further explanation.
The ground bus on the sub panel is already connected to the sub pannel box right? so wouldn't current from a fault flow through that metal raceway and potentially through you if you bridged the two boxes regardless of the neutral bus being connected in the sub pannel? If the ground bus is not connected to the sub pannel box, then how would a fault on that box trip the breaker?
I can understand why you wouldn't want them connected during regular operation; (no fault) because in that case the ground wires and the pannel boxes would act as an exposed neutral line but I don't understand why it matters durring a fault.
@rustediron4062 That’s been driving me crazy but reading your comment I think that’s the answer. I think in regular operation you would be safe by touching the two panels (when properly connected). At ground fault it wouldn’t matter how they’re connected you’d still may get some current. At least that’s what I think.
Did you find any answers?
@@GeronimoChannel so if everything is connected properly the breaker will trip almost instantly from a ground fault which essentially makes the risk of touching both during a fault negligible.
If bonded in both places it makes it so during normal operation the ground wire has a path for current to travel which is not supposed to have current for any other reason than during a fault.
@@Hoaxiin i see. Thanks!
A great video -- very helpful to understand why and why not
Our inspector does not allow a ground rod on a sub panel, he said all grounds must run thru the main disconnect. I argued about it, but HE is the man.
wow, that was an excellent video! thank you so much! you explained that so good.
Great animations really help!
I think there's an error here: 13:24 the ground fault current will travel on the metal raceway even if you don't bond the ground and neutral in the subpanel, because the subpanel ground bus bar is bonded to the panel chassis via the screws that attach it to the chassis. The reason that you don't bond ground and neutral in the subpanel is to prevent the ground wire from carrying return current from the subpanel to the main panel during normal operation.
Notice at 13:07 it states "equivalent path shown for simplicity" as it's difficult to animate current through the case.
@@EngineeringMindset Yeah I get that. I just don't understand why you said "if there's a metal raceway between panels, the current will flow on this also" as a result of ground and neutral being bonded in the sub panel. Current will flow on the raceway whether or not ground and neutral are bonded, because the ground bus bars are bonded to the frames of both panels. And the thing about a human carrying current between panels is also possible even without bonding ground and neutral in the subpanel, for the same reason.
See @rustediron4062 and @cornpop7805 comments for basically the same objection, worded differently.
I think my former home owners did their own sub panel next to the main one in the basement, I figure this because there were 20 amp breakers on 14ga wire. Thank you for this now I can check to make sure they wired the sub panel correctly.
I see new meter pans include provision for bonding neutral. Considering older installs have bonding screw installed at main panel... what is best practice?
This is one of the best videos I've seen on the topic; very good.
Glad to hear that!
The King of Building services videos!!!
Nice video shot, well done, thank you for sharing it with us :)
Brilliant mate. absolutely brilliant. I have struggled to explain this to people more times than i can count. Gonna save me so much time haha! I run into one or more of the various netural or ground issues presented here on about 50% of all the properties. Even worse odds in some areas 😂😂😂
Glad it helped
Would like to see a video of yours explaining the differences between the American and European electrical systems in detail. Great video as always!
Great suggestion!
@@EngineeringMindset As would making it clear at the beginning of the video the region of the world being discussed. I assume your discussion applies to the Americas and not Europe.
love the explanations
Great video a sharp novice could understand it on the 1st run through the video, it would probably take a few pauses or rewinds for someone who has no concept to get how it all works. Well done!👍👍
Great video. Any chance of getting a video on how a slip ring assembly works ?
I did buried wire locating for awhile and it really made me figure out grounding. I was always disappointed when no one else understood...
Awesome video... would love to see same video on generator transfer panels with bonded/unbonded generators.
It's really helpful👍🏼
Perfect demonstration! Thanks alot
Wow, the title doesn’t do this awesome video Justice! Try this… ‘How sub-panels really work and why, why, why GFI’ add 1 min more on GFI and talk about the arc fault breakers for 1 min. I was shocked at how good this was! :)
The Engineering Mindset drinking game: "Bus bar."
Sounds like a good excuse to drink