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
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. 😎
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."_
@@PressRecord777You 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.
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
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 UA-cam. We just need to organize the content.
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.
@@FreighedNoughtyes 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
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 UA-cam 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!
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!
@@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.
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.
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.
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.
I work in the TV and film industry and have been learning this as I work more powerful lights. The set lighting technician manual I've been reading prepared me surprisingly well to understand this video and helped me appreciate how well it is made. Excellent video!
A great explanation. It helps a lot. Whenever I hear the terms 'grounding conductor' and 'grounded conductor', I have to stop and think carefully about the terms. They sound so similar but have very different meaning. I've had many tell me, 'it doesn't matter, they're both connected together anyway.' But here you explain exactly why it DOES matter.
I believe a rod at the main and also at the sub would create a current loop. the shield in process control inputs are only grounded in the control cabinet and left unconnected at the process sensor input to prevent a current loop between the control cabinet and the field sensor. A current loop would add noise in the input.
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.
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!
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.
Pause during the key moments which highlight the main concepts so that viewers can think through the points themselves. UA-cam is great because people can pause the videos at these key points but many people won’t do that and so may miss some things. Otherwise, excellent video! Clear graphics and comprehensive coverage of the concepts!
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...
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
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!
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❤❤❤
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.
@@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.
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?
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
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.
You need to share this with my old electrical circuits engineering professor. The majority of those who teach circuits don't understand how panels are wired or how circuit logic works.
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.
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!!
My brain still can't quite grasp why what happens when you do it wrong- but you helped me understand how to do it right and how to not do it wrong and that's what counts. Thank you 😊
I notice that a lot of comments, from what sounds like veteran electricians, are very often along the lines of: "I did it for 20 years and not know why, I was just taught not to" or "nobody ever explained it as simple as this for me to understand" or "I just did it out of habit, never bothered to ask why". It's mind boggling to me, that there are professions in which training and education simply convey the "what" and "how", but not the "why". As mechanic, the "why" is the reason how I got REALLY good at diagnostics and repairs. Especially in those cases where someone did something that causes a problem, looks right, but isn't. Fixing things a way that will work, but isn't safe or the proper procedure to ensure a lasting piece of equipment, bypassing, rather than fixing the root cause.
You learn it in school, they probably didn't pay attention and never ever bothered to actually learn it on their own. Makes me wonder how they ever got any work done not understanding the basics of electrical circuits. We learned this stuff in electrical theory 1
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!
@@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.
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.
Such a helpful video, thanks! This is a great resource while I plan to add electrical conduit and receptacles to my new garage workshop. I had a subpanel professionally installed but wanted to DIY the rest and I feel I've got a much better understanding now. I appreciate how much introductory information you covered, and how concisely it was presented, to give context to the main question in the video title :) Your diagrams illustrated what was being narrated perfectly. The NEC citations were helpful, too!
@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.
The video said this already, but I'll state it another way. I believe the neutral is to be bonded at the first point of disconnect. Specifically, the first point of disconnect, relative to the service. For residential, I believe this means the first point of disconnect after the service meter socket.
The neutral-to-ground bonding really belongs in the transformer based on the physics behind its purpose, rather than in the panelboard or disconnect. That way, you accomplish this bonding as soon as that particular system is derived. However, because it is very common that the transformer is a utility-owned transformer, rather than a customer-owned transformer, the NEC makes a compromise to require it in the service disconnect instead, so it is at the first piece of customer-owned equipment where the NEC governs. In a customer-owned transformer, the NEC either allows you do do this in the transformer, or in the 240.21(C) disconnect as if it were a service disconnect, but not both. My recommendation is to do it in the transformer, and treat everything connected to the transformer's secondary, as a subpanel.
Although the first 75% of this video has nothing to do with the topic it does has a lot to offer. You are indeed close but no cigar. The moment either phase hits the ground regardless of neutral the dead short will trip the breaker. 100% correct about the return path carrying current to the equipment through the bond.
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.
A+ on the illustrations - my dad was an electrician and i learned much of what i know about writing from him, but his explanations were nowhere near this clear
Thank you for this, extremely useful. It made it clear that my outbuilding sub-panel was incorrectly grounded, which I suspected, and why that needed to be corrected immediately. Excellent work.
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.
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.
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! :)
Love this videos. Do you have one like this explaining when you connect a generator to the main box with an interlock switch and why you need a floating neutral?
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.
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.
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.
as an electrical apprentice in school, i wish they would show videos of this quality instead of outdated, audio distorted, old videos with no real diagrams
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 have seen so many arguments in electrician Facebook groups about this subject. If anyone asks why they sure told they know nothing and they need to hire an electrician. It’s hilarious to be honest. This video explains everything that they refused (or perhaps couldn’t properly explain) to explain. Thank you so very much, I’m going to need to watch it a couple times to fully understand it but the graphics were great additions to help understand it. It also explained things that I didn’t even think to wonder about. Like the gfci outlets and the variations on how electricity can be brought into a home.
One will observe that most sub-panels installed before the 1970’s have both ground and neutrals bonded. Many of these pre-70’s homes only had a only a couple of grounded branch circuits in the sub-panel, usually a bath and kitchen. These panels can be upgraded by either separating the ground and neutrals and adding a ground bar and running a separate appropriately sized ground back to the main panel or replacing with a modern sub-panel. The older main panels are usually grounded to the water service entrance pipe.
Could you have a general GFCI for the whole system? Or does it only work on one circuit at a time? Great video, I'm by no means an electrician but I still understood most concept in this video! Much more than physics class taught me in 16min lol
Yes. Countries that use 240 volts adopted GFCIs (aka Residual Current Devices) earlier due to the higher risk of electrocution. They usually have one big RCD supplying a group of simple over-current breakers. In North America, GFCIs were first required only in special cases (first swimming pool lights, then kitchens and bathrooms, then anywhere outdoors, etc). This, in addition with how our panels are physically arranged, lead to ground fault protection being done on a per-circuit basis.
Hi Paul. I've never worked on the US. Electrical system Only the UK. But I thought you explained that extremely well. I understood it with no problem whatsoever, It must have taken you a long time to put this together, but I do appreciate your efforts so. thanks for sharing.
Thanks, Brian. This video took a long time to make indeed. I will cover other systems in detail too. The Norwegians have a strange setup that would be interesting to cover.
13:23 Even if in such incorrectly wired system there was no ground fault, objectionable current would flow from the subpanel neutral terminal to the ground terminal, and then to the main panel. In other words, there would be current flow in the ground wires under normal conditions, which is not OK.
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.
Thank you so much for these videos, which are tremendously helpful and informative. I'm still just a beginner, so apologies if this is not the right way to frame the question, but I am wondering if it makes any practical difference whether neutral and ground are separated in the sub-panel in terms of when the breaker is tripped. I understand (thanks to your videos!) that you want all of the current from a ground fault to flow along the low-resistance neutral conductor all the way back to the main service panel because that ensures the most efficient path to trip the breaker as quickly as possible, but wouldn't it effectively trip the breaker almost instantaneously in either case? Even if some of the flow were diverted to the neutral wire through an incorrectly installed sub-panel joining the neutral & ground wires, presumably there is so much current still traveling through the less-resistant neutral that it wouldn't make a recognizable difference to the homeowner. I'm definitely NOT suggesting this means it doesn't matter, I'm just wondering if this scenario means that a ground fault wouldn't alert the the homeowner to the problem of the incorrectly installed sub-panel. It would happen so fast you just couldn't notice. THANK YOU! These videos are amazing. Even if I wasn't studying them for practical purposes, I would find them kinda fascinating.
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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.
Can u guys do a video on comparator 🙏
@@manickn6819w
WOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOW
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
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.
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."_
@@PressRecord777You 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.
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 UA-cam. 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!
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?
@@FreighedNoughtyes 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
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.
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 UA-cam 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!
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!
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!
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.
You have the best explanations on the platform. Please keep doing what you do!
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.
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.
I work in the TV and film industry and have been learning this as I work more powerful lights. The set lighting technician manual I've been reading prepared me surprisingly well to understand this video and helped me appreciate how well it is made. Excellent video!
A great explanation. It helps a lot. Whenever I hear the terms 'grounding conductor' and 'grounded conductor', I have to stop and think carefully about the terms. They sound so similar but have very different meaning.
I've had many tell me, 'it doesn't matter, they're both connected together anyway.' But here you explain exactly why it DOES matter.
Nicely done. Many people don’t understand the ground/ neutral scenerios and you explained it very well.
Thank you
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.
I believe a rod at the main and also at the sub would create a current loop. the shield in process control inputs are only grounded in the control cabinet and left unconnected at the process sensor input to prevent a current loop between the control cabinet and the field sensor. A current loop would add noise in the input.
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.
This has been explained to me 3-4 times and this is the first time I’ve understood it. Thank you!
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!
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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.
This is I will say the best video I've seen explaining sub panel wiring and faults that could occur if miswired. Good job!
Pause during the key moments which highlight the main concepts so that viewers can think through the points themselves. UA-cam is great because people can pause the videos at these key points but many people won’t do that and so may miss some things.
Otherwise, excellent video! Clear graphics and comprehensive coverage of the concepts!
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...
I'm going to make sure that all my apprentices watch this video. It is the most cogent explanation of how these wires all work together.
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
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!
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❤❤❤
Easily the single BEST video I have EVER seen on this subject! Really, really well done!
Spot on !!!
Licensed master electrician of 40 years in NY
Thanx for excellent vids....
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.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ua-cam.com/video/Qi0ynSQw-wc/v-deo.html
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?
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
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.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ua-cam.com/video/Qi0ynSQw-wc/v-deo.html
You need to share this with my old electrical circuits engineering professor. The majority of those who teach circuits don't understand how panels are wired or how circuit logic works.
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.
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!!
The best and most illustrative explanation I have seen!. Wow! The detail, the graphics, the NEC references, the accent! Great video.
My brain still can't quite grasp why what happens when you do it wrong- but you helped me understand how to do it right and how to not do it wrong and that's what counts. Thank you 😊
I notice that a lot of comments, from what sounds like veteran electricians, are very often along the lines of: "I did it for 20 years and not know why, I was just taught not to" or "nobody ever explained it as simple as this for me to understand" or "I just did it out of habit, never bothered to ask why".
It's mind boggling to me, that there are professions in which training and education simply convey the "what" and "how", but not the "why".
As mechanic, the "why" is the reason how I got REALLY good at diagnostics and repairs. Especially in those cases where someone did something that causes a problem, looks right, but isn't. Fixing things a way that will work, but isn't safe or the proper procedure to ensure a lasting piece of equipment, bypassing, rather than fixing the root cause.
You learn it in school, they probably didn't pay attention and never ever bothered to actually learn it on their own. Makes me wonder how they ever got any work done not understanding the basics of electrical circuits. We learned this stuff in electrical theory 1
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!
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.
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!
Such a helpful video, thanks! This is a great resource while I plan to add electrical conduit and receptacles to my new garage workshop. I had a subpanel professionally installed but wanted to DIY the rest and I feel I've got a much better understanding now. I appreciate how much introductory information you covered, and how concisely it was presented, to give context to the main question in the video title :) Your diagrams illustrated what was being narrated perfectly. The NEC citations were helpful, too!
A great explanation that I have shared with my son who is new home owner as he tries to understand basic electricity.
@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.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ua-cam.com/video/Qi0ynSQw-wc/v-deo.html
Wow! The detail, the graphics, the NEC references, the accent! Great video
As an individual learning with minimal (non existent) guidance from the company I work for. Thank you sir for your concise explanation.
The video said this already, but I'll state it another way.
I believe the neutral is to be bonded at the first point of disconnect. Specifically, the first point of disconnect, relative to the service. For residential, I believe this means the first point of disconnect after the service meter socket.
The neutral-to-ground bonding really belongs in the transformer based on the physics behind its purpose, rather than in the panelboard or disconnect. That way, you accomplish this bonding as soon as that particular system is derived. However, because it is very common that the transformer is a utility-owned transformer, rather than a customer-owned transformer, the NEC makes a compromise to require it in the service disconnect instead, so it is at the first piece of customer-owned equipment where the NEC governs.
In a customer-owned transformer, the NEC either allows you do do this in the transformer, or in the 240.21(C) disconnect as if it were a service disconnect, but not both. My recommendation is to do it in the transformer, and treat everything connected to the transformer's secondary, as a subpanel.
@carultch
I agree with what you have said.
I was merely summarizing the video, which seemed to assume a municipal transformer.
Finally, a video that explains the WHY of bonded neutral-ground connections! Thank you!
Thank you for using your sponsorship to explain how information is being geolocation controlled.
Although the first 75% of this video has nothing to do with the topic it does has a lot to offer. You are indeed close but no cigar. The moment either phase hits the ground regardless of neutral the dead short will trip the breaker. 100% correct about the return path carrying current to the equipment through the bond.
I did buried wire locating for awhile and it really made me figure out grounding. I was always disappointed when no one else understood...
Am going to watch this video over and over until I understand every scenario. Thanks TEM
This is by far the best explanation I have ever seen. Great job
Great explanation. I now understand after so many years. Keep up the good work.
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.
A+ on the illustrations - my dad was an electrician and i learned much of what i know about writing from him, but his explanations were nowhere near this clear
This is a very clear and thorough explanation of this question. Well done!
Thank you for this, extremely useful.
It made it clear that my outbuilding sub-panel was incorrectly grounded, which I suspected, and why that needed to be corrected immediately. Excellent work.
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!
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ua-cam.com/video/Qi0ynSQw-wc/v-deo.html
Literally it was this video that provided the lightbulb moment I needed to finish my solar installation. Thanks g!
Glad I could help!
The Engineering Mindset drinking game: "Bus bar."
Sounds like a good excuse to drink
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.
Thanks! the visualization with the audio commentary really helped me understand this a lot more.
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! :)
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 :)
These videos are an amazing training resource. I would love to see similar ones for European standars!
Thank you man... This is the best-explained answer to this question I've ever found since this question began plaguing my mind.
Love this videos. Do you have one like this explaining when you connect a generator to the main box with an interlock switch and why you need a floating neutral?
I'll have to watch this again. There is good info here that didn't sink in far enough.
I need to watch it again at a lower speed. 😅
Me 2 bro.. need to watch it many times...
This video is so incredibly clear and the animations do a great job of further describing the dialog. Excellent resource, thank you for creating!
Finally. A clear and coherent explanation delivered in a way that even I can understand it!
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.
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.
Thank you for the explanation, maybe i am dumb but if we bond neutral and ground in the main panel anyway, why do we need both of them?
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.
as an electrical apprentice in school, i wish they would show videos of this quality instead of outdated, audio distorted, old videos with no real diagrams
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.
This is a fantastic lesson. Love the illustrations, love the "what if's"!
Absolute best video for the topic!
Thank you for explaining at 13:30 how a person could get shocked by the parallel return paths.
BEST explanation I have ever seen or heard. Bar none!!!! Well done Sir.
I have seen so many arguments in electrician Facebook groups about this subject. If anyone asks why they sure told they know nothing and they need to hire an electrician. It’s hilarious to be honest. This video explains everything that they refused (or perhaps couldn’t properly explain) to explain. Thank you so very much, I’m going to need to watch it a couple times to fully understand it but the graphics were great additions to help understand it. It also explained things that I didn’t even think to wonder about. Like the gfci outlets and the variations on how electricity can be brought into a home.
This is one of the best videos I've seen on the topic; very good.
Glad to hear that!
One will observe that most sub-panels installed before the 1970’s have both ground and neutrals bonded. Many of these pre-70’s homes only had a only a couple of grounded branch circuits in the sub-panel, usually a bath and kitchen. These panels can be upgraded by either separating the ground and neutrals and adding a ground bar and running a separate appropriately sized ground back to the main panel or replacing with a modern sub-panel. The older main panels are usually grounded to the water service entrance pipe.
Could you have a general GFCI for the whole system? Or does it only work on one circuit at a time? Great video, I'm by no means an electrician but I still understood most concept in this video! Much more than physics class taught me in 16min lol
Yes. Countries that use 240 volts adopted GFCIs (aka Residual Current Devices) earlier due to the higher risk of electrocution. They usually have one big RCD supplying a group of simple over-current breakers. In North America, GFCIs were first required only in special cases (first swimming pool lights, then kitchens and bathrooms, then anywhere outdoors, etc). This, in addition with how our panels are physically arranged, lead to ground fault protection being done on a per-circuit basis.
Great video. Any chance of getting a video on how a slip ring assembly works ?
Hi Paul. I've never worked on the US. Electrical system Only the UK. But I thought you explained that extremely well. I understood it with no problem whatsoever, It must have taken you a long time to put this together, but I do appreciate your efforts so. thanks for sharing.
Thanks, Brian. This video took a long time to make indeed. I will cover other systems in detail too. The Norwegians have a strange setup that would be interesting to cover.
@@EngineeringMindset Looking forward to seeing that!
@@EngineeringMindset🇳🇴🥳 please do!
The King of Building services videos!!!
I'm glad to see that you're now able to make new videos
Have for months now
Nice 👍👍👏👏😊😊
The explanation + animation really helps! Thank you!
What a great video you went all the way to the nitty gritty... This will automatically go on my electrical playlist for UA-cam
13:23 Even if in such incorrectly wired system there was no ground fault, objectionable current would flow from the subpanel neutral terminal to the ground terminal, and then to the main panel. In other words, there would be current flow in the ground wires under normal conditions, which is not OK.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ua-cam.com/video/Qi0ynSQw-wc/v-deo.html
Great video, Grounding, bonding, neutrals are confusing. Thank you.
You did a phenomenal job explaining trunk/branch electrical. Cheers! 🍻
Glad you enjoyed it!
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.
Thank you so much for these videos, which are tremendously helpful and informative. I'm still just a beginner, so apologies if this is not the right way to frame the question, but I am wondering if it makes any practical difference whether neutral and ground are separated in the sub-panel in terms of when the breaker is tripped. I understand (thanks to your videos!) that you want all of the current from a ground fault to flow along the low-resistance neutral conductor all the way back to the main service panel because that ensures the most efficient path to trip the breaker as quickly as possible, but wouldn't it effectively trip the breaker almost instantaneously in either case? Even if some of the flow were diverted to the neutral wire through an incorrectly installed sub-panel joining the neutral & ground wires, presumably there is so much current still traveling through the less-resistant neutral that it wouldn't make a recognizable difference to the homeowner. I'm definitely NOT suggesting this means it doesn't matter, I'm just wondering if this scenario means that a ground fault wouldn't alert the the homeowner to the problem of the incorrectly installed sub-panel. It would happen so fast you just couldn't notice.
THANK YOU! These videos are amazing. Even if I wasn't studying them for practical purposes, I would find them kinda fascinating.
We just published a new Ground fault, short circuit and arc fault video, so much detail! Link HERE➡️: ua-cam.com/video/Qi0ynSQw-wc/v-deo.html