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
I have a panel in the garage with a external 240 box for my welder but I want to switch it to a 120v 30amp, the box used is a double 30amp buss fuses. I can't find any posts on doing the switching. The wires running into the 240 box should be 120 and 120, is switching them to 120v 30 amp just using one
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!
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!
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
@@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.
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!
Its not so much about how you said it but more about the point the the ground would at that point because a parallel return path back to the main panel. That is dangerous.
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.
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.
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.
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!
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❤❤❤
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...
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.
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!
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!!
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 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.
11:50 will current not also flow in the metal casing here? Thr ground bus bar in the sub panel is connected to the metal casing, the neutral is connected to the metal casing in the main panel, the two metal casing are connected via the feeder conduit, so wouldn't current be able to flow through the casings to the bonding jumper to neutral?
During fault conditions, yes. The casing and grounding wire will share the parallel current. But, during normal circumstances, no. The current is limited to the live and neutral wires. Since current needs a closed loop path to flow, a dead-end bond between neutral and ground will not sustainably allow current to flow between neutral and ground. A little current flows during the first second when they are achieving electrostatic equilibrium, but no current flows continuously thereafter.
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
@10:33 What is the role of the 2- pole breaker in the main panel? Is this redundant? If the branch breaker trips first, then presumably the 2-pole breaker would not. At 12:03, for a ground fault, you get a huge current, and the "breaker" trips. You show the sub panel breaker tripping but not the double pole breaker in the main.WHY?
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!
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!
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!
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.
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.
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.
@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.
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.
5:28 in video, im automotive DC, i show my new guy's your multi meter will only show difference in voltage. 2 positive wires meeting dont do anything, and measuring with multi meter would show 0 Volts. Is this different with AC current do to the wave lengths? Does multi meter show 240 volts with 2 positives?
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?
@@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.
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.
Just stumbled upon your YT Channel. EXCELLENT VISUAL REPRESENTATION OF YOUR MATERIAL !!!!! THEBEST I"VE SEEN !!!! I help my youngest Son occasionally , he's a RED SEAL JOURNEYMAN ELECTRICIAN here in Canada. He explains things to me , however , they do not stay with me or he totally loses me with his explanation. You've simplified details with this video and , thus , I am eternally grateful for it. I will indeed watch all of your video's. Great , great educational channel. Thank you.
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.
At 12:00, isn't there also a potential parallel path for ground fault current through a metal conduit or person between the two panels? And is it really a big deal if there is? The resistance of the ground conductor should be very low compared to the load resistance, so there shouldn't be much voltage between the metal cases.
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.
13:29 If double bonded gournd, will all metal parts from appliances become electricfy? or just the rail way, what happen to the GFCI breaker function in the sub pannel if that happen?
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
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!
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.
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.
When using an offgrid solar setup, where do you run the neutral connection from that goes to the inverter output? Do you run the neutral from the main panel or do u take the connection from the sub panel? Does it matter where it comes from seeing that its the same neutral in the main box as well as in the sub panel?
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.
If the pole mounted transformer is only connected to one phase, how can the bus bars have tension between them? Or how does Hot1 and hot 2 (1:49) come out with voltage between them when the PMT is only connected to one phase?
I am reasonably certain that the high voltage side of the transformer is connected between TWO phases. I think that is a mistake in the video, or maybe it is done that way somewhere but not on the transformers that I have seen.
The transformer is also connected to the neutral on the pole (ignoring rare cases where a neutral isn't used.) It's usually bonded to the metal housing, so it's not as obvious as the tap to the phase. All 3 phases share the same neutral, because it only has to carry the imbalance between the 3 phases, so, the max current it would need to carry is a single phase, which is why it is sized the same.
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.
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.
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.
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 😊
Might not be two code anymore, but what about a subpanel (in a separate building) with a 3-wire connection to the main? Is it safe and should ground and neutral still be separated? I have an existing garage (built 30 years ago) with 3 wires from the main panel; two hot and a neutral, NO GROUND WIRE from the main panel. The building is grounded separately and there are no other metal connections like pipes between the house and the garage. The existing panel currently has ground and neutral on the same bars. Seems like this would be resulting in current through the subpanel's ground wire.
👏 👏 👏👏👏 bravo!!! A most excellent presentation…well done sir! This is a ‘must watch’ for anyone in the electrical trade, from manufacturer tech support, the supply chain staff to installation apprentices ….well done indeed 👏👏👏👏
Thank you so much for this video. There are a wide variety of service and panel scenarios and because of the way your video explains things, its principles can be applied to virtually any panel scenario I can think of. I really appreciate the thought that went into the video and how things were explained so perfectly! THANK YOU!
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?
In my situation, I am looking at a barn that is connected to an overhead feeder line consisting of a bare neutral / support cable plus two power lines, comprising a 240V balanced source. The feeder line connects to a main breaker and a meter panel at the other end of the overhead line. Is it necessary to add another conductor to the overhead line, so that ground and neutral can be entirely separate at the barn? There is a panel with main disconnect at the barn. In general, I am still puzzled about why it is OK to connect ground to neutral at the main panel connecting to the power company. If the neutral breaks in the overhead line from the supply transformer (which seems highly likely since it's also the support cable) then you still have unbalanced voltage at the panel ground. To prevent this, one would need a separate ground and neutral all the way back to the isolation transformer.
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.
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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
You are responsible for your own education. Don't be lazy.
Same? Theirs no way you've been doing this for 20 years.
Same
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.
I have a panel in the garage with a external 240 box for my welder but I want to switch it to a 120v 30amp, the box used is a double 30amp buss fuses. I can't find any posts on doing the switching. The wires running into the 240 box should be 120 and 120, is switching them to 120v 30 amp just using one
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!
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!
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.
You have the best explanations on the platform. Please keep doing what you do!
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!
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!
Its not so much about how you said it but more about the point the the ground would at that point because a parallel return path back to the main panel. That is dangerous.
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.
Nicely done. Many people don’t understand the ground/ neutral scenerios and you explained it very well.
Thank you
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.
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
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!
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
This is I will say the best video I've seen explaining sub panel wiring and faults that could occur if miswired. Good job!
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.
Easily the single BEST video I have EVER seen on this subject! Really, really well done!
Thanks!
I love the what If scenarios. Helps me understand .
Glad it was helpful! Thank you
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❤❤❤
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...
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.
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!
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!!
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 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
11:50 will current not also flow in the metal casing here? Thr ground bus bar in the sub panel is connected to the metal casing, the neutral is connected to the metal casing in the main panel, the two metal casing are connected via the feeder conduit, so wouldn't current be able to flow through the casings to the bonding jumper to neutral?
During fault conditions, yes. The casing and grounding wire will share the parallel current.
But, during normal circumstances, no. The current is limited to the live and neutral wires.
Since current needs a closed loop path to flow, a dead-end bond between neutral and ground will not sustainably allow current to flow between neutral and ground. A little current flows during the first second when they are achieving electrostatic equilibrium, but no current flows continuously thereafter.
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
@10:33 What is the role of the 2- pole breaker in the main panel? Is this redundant?
If the branch breaker trips first, then presumably the 2-pole breaker would not. At 12:03, for a ground fault, you get a huge current, and the "breaker" trips. You show the sub panel breaker tripping but not the double pole breaker in the main.WHY?
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!
The best and most illustrative explanation I have seen!. Wow! The detail, the graphics, the NEC references, the accent! Great video.
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!
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!
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
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.
Spot on !!!
Licensed master electrician of 40 years in NY
Thanx for excellent vids....
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!
@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
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.
This is by far the best explanation I have ever seen. Great job
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 :)
5:28 in video, im automotive DC, i show my new guy's your multi meter will only show difference in voltage.
2 positive wires meeting dont do anything, and measuring with multi meter would show 0 Volts. Is this different with AC current do to the wave lengths? Does multi meter show 240 volts with 2 positives?
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?
A great explanation that I have shared with my son who is new home owner as he tries to understand basic electricity.
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.
This video is so incredibly clear and the animations do a great job of further describing the dialog. Excellent resource, thank you for creating!
Thanks! the visualization with the audio commentary really helped me understand this a lot more.
Wow! The detail, the graphics, the NEC references, the accent! Great video
Finally, a video that explains the WHY of bonded neutral-ground connections! Thank you!
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.
Just stumbled upon your YT Channel. EXCELLENT VISUAL REPRESENTATION OF YOUR MATERIAL !!!!! THEBEST I"VE SEEN !!!! I help my youngest Son occasionally , he's a RED SEAL JOURNEYMAN ELECTRICIAN here in Canada. He explains things to me , however , they do not stay with me or he totally loses me with his explanation. You've simplified details with this video and , thus , I am eternally grateful for it. I will indeed watch all of your video's. Great , great educational channel. Thank you.
These videos are an amazing training resource. I would love to see similar ones for European standars!
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.
The King of Building services videos!!!
At 12:00, isn't there also a potential parallel path for ground fault current through a metal conduit or person between the two panels? And is it really a big deal if there is? The resistance of the ground conductor should be very low compared to the load resistance, so there shouldn't be much voltage between the metal cases.
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
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.
This is a very clear and thorough explanation of this question. Well done!
Finally. A clear and coherent explanation delivered in a way that even I can understand it!
13:29 If double bonded gournd, will all metal parts from appliances become electricfy? or just the rail way, what happen to the GFCI breaker function in the sub pannel if that happen?
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
The explanation + animation really helps! Thank you!
This is a fantastic lesson. Love the illustrations, love the "what if's"!
Absolute best video for the topic!
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!
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.
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.
Thank you man... This is the best-explained answer to this question I've ever found since this question began plaguing my mind.
When using an offgrid solar setup, where do you run the neutral connection from that goes to the inverter output? Do you run the neutral from the main panel or do u take the connection from the sub panel? Does it matter where it comes from seeing that its the same neutral in the main box as well as in the sub panel?
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 for using your sponsorship to explain how information is being geolocation controlled.
Literally it was this video that provided the lightbulb moment I needed to finish my solar installation. Thanks g!
Glad I could help!
One of the best segues into an ad I've ever seen!
If the pole mounted transformer is only connected to one phase, how can the bus bars have tension between them? Or how does Hot1 and hot 2 (1:49) come out with voltage between them when the PMT is only connected to one phase?
I am reasonably certain that the high voltage side of the transformer is connected between TWO phases. I think that is a mistake in the video, or maybe it is done that way somewhere but not on the transformers that I have seen.
The transformer is also connected to the neutral on the pole (ignoring rare cases where a neutral isn't used.) It's usually bonded to the metal housing, so it's not as obvious as the tap to the phase. All 3 phases share the same neutral, because it only has to carry the imbalance between the 3 phases, so, the max current it would need to carry is a single phase, which is why it is sized the same.
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.
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.
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!
BEST explanation I have ever seen or heard. Bar none!!!! Well done Sir.
Great explanation. I now understand after so many years. Keep up the good work.
What a great video you went all the way to the nitty gritty... This will automatically go on my electrical playlist for UA-cam
Absolutely love your content. Specifically, the visual aids and your ability to teach in a clear and concise way! Thanks 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 😊
The Engineering Mindset drinking game: "Bus bar."
Sounds like a good excuse to drink
This is one of the best videos I've seen on the topic; very good.
Glad to hear that!
I'm glad to see that you're now able to make new videos
Have for months now
Nice 👍👍👏👏😊😊
Might not be two code anymore, but what about a subpanel (in a separate building) with a 3-wire connection to the main? Is it safe and should ground and neutral still be separated?
I have an existing garage (built 30 years ago) with 3 wires from the main panel; two hot and a neutral, NO GROUND WIRE from the main panel. The building is grounded separately and there are no other metal connections like pipes between the house and the garage. The existing panel currently has ground and neutral on the same bars. Seems like this would be resulting in current through the subpanel's ground wire.
👏 👏 👏👏👏 bravo!!! A most excellent presentation…well done sir!
This is a ‘must watch’ for anyone in the electrical trade, from manufacturer tech support, the supply chain staff to installation apprentices ….well done indeed 👏👏👏👏
Am going to watch this video over and over until I understand every scenario. Thanks TEM
Thank you so much for this video. There are a wide variety of service and panel scenarios and because of the way your video explains things, its principles can be applied to virtually any panel scenario I can think of. I really appreciate the thought that went into the video and how things were explained so perfectly! THANK YOU!
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! :)
Thanks!
Thank you!
You did a phenomenal job explaining trunk/branch electrical. Cheers! 🍻
Glad you enjoyed it!
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?
In my situation, I am looking at a barn that is connected to an overhead feeder line consisting of a bare neutral / support cable plus two power lines, comprising a 240V balanced source. The feeder line connects to a main breaker and a meter panel at the other end of the overhead line. Is it necessary to add another conductor to the overhead line, so that ground and neutral can be entirely separate at the barn? There is a panel with main disconnect at the barn.
In general, I am still puzzled about why it is OK to connect ground to neutral at the main panel connecting to the power company. If the neutral breaks in the overhead line from the supply transformer (which seems highly likely since it's also the support cable) then you still have unbalanced voltage at the panel ground. To prevent this, one would need a separate ground and neutral all the way back to the isolation transformer.
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.
Excellent Video and the graphics Really help to show the current flow. I am going to have this added to my technicians study materials! Thank You
Great video. You are so clear in your explanation. The best illustrations I've seen. I will definitely be watching more.
is there a designated spot in my service panel where the ground wire from the subpanel connects. Or does it connect to the neutral/ ground bus bar