Grounding and Bonding
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- Опубликовано: 25 май 2024
- This is a brief walk through of a simple grounding and bonding system, and what happens with the flow of current in normal operation, and in a ground fault condition. There are no Code Rule references, however please be advised terminologies follow the 2015 Canadian Electrical Code.
Please be advised that in the last scenario, where there is only the path through ground, depending upon your location, there may not be sufficiently low impedance to trip the main overcurrent. Always ensure proper continuity of all grounding and bonding systems with the help of a licensed electrician.
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FINALLY! AFTER 3 YEARS OF ELNC ENGINEERING AND 100 VIDEOS ON THE SUBJECT!!! SOMEONE WHO UNDERSTANDS LANGUAGE AND KNOWS WHAT'S GOING ON WITH GROUNDING!!!
Thank you! I don't think I'll ever know it all though.
Peter, if it's language that you are heralding, then you should know that it is incorrect to cite Ohm's Law when speaking about impedance in an AC circuit. Only in a purely resistive circuit, that is also Ohmic, can Ohm's Law be cited or applied.
Many people simplify the term ohms law into a formula. Using the term ohms law as a blanket statement is very common in electrical analysis, which I'm sure you're very aware of. I'm well aware of what it truly means, but 9.9 out of ten people when asked what ohms law is will regurgitate the formula and often substitute Z for R. Does it mean it's correct? No. Does the formula still work to calculate the equivalent current flow in a circuit based on oppositionial ohmic equivalents? Yes.
Should we still use the term ohms law? Yes. To give learners an easier to digest theory for circuit analysis without diving into considerably deeper level physics to get the point across that ohms go up amps go down.
This was a great way to learn power panel's jigsaw puzzle particularly grounding, bonding and neutral. Hope hit 5M in your life. Generations will come and learn from this wow video.
Excellent video. I have been teaching this for years. I find that about 90% of electricians and engineers think that the fault goes to earth ground. Some have even argued with me on this. Again excellent video!
Thanks for watching! I've had the same arguments so I'm glad I'm not alone haha. I tell my students if the current is going to ground you need to fix it or move.
schulerruler I wrote a comment about the current going to ground Electrode. Then I saw all the comments and your response, so I deleted it. Respectfully, Kevin
I think one of the biggest problems understanding this is understanding that when talking about ground all grounds are not created equal. You have your grounding rod or earth ground. You have your metal body of your car or the chassis ground. You have your ground on your outlet, the fault current return ground. You have your shield on your guitar cable and when you get a buzzing sound they say they have a bad or broken ground. When you weld and you can't strike an arc you check the welding ground cable to the work piece. I think you've done a great job explaining ground in this application.
Thank you! I agree, there are many different systems with the same common "ground" term when they are very different systems.
Great! Thank you! Today I tried to explain the reasoning for grounding and bonding to an employee, and your illustration is WAY more efficient than anything I could come up with.
Thank you for watching! I really like your metaphor for grounding as using an anchor in a ship. It's perfect!
Great video , so many people think the grounding electrode will clear a fault or remove shock potential and it won’t and your video clearly shows how you clear a fault or remove shock potential.
Best video so far and it’s been 4 years , thank you good sir 😮💨
Thank you for the support!
@@schulerruler any time !
This was a great help to a noob trying to learn more about this! Thank you for making this available!
Thanks for watching! I'm happy it was able to help you.
Nice video. Showing the path of current step by step makes your explanation very clear. During the last part of your presentation, I would add that there's a non-zero impedance in the dirt between the house ground/dirt location and the transformer ground/dirt location. The breaker will trip only if that impedance has a relatively low value (typically 5 ohms or less). Since it is virtually impossible to configure a low impedance dirt connection in some locations, you should never rely on the idea that a fault into the dirt will trip the breaker. You might ask, if that's true, then what's the purpose of that dirt connection. Its purpose is to dump lightning and static induced charge into the ground. Whenever there's a lightning strike close by, the current flowing in the lightning bolt will create a very large changing magnetic field. That changing magnetic field will induce a voltage in all of the metal parts of the electrical system (conduits, wires, etc). If you don't connect that system to a dirt ground, those metal parts can provide a pretty nasty shock. So, what I am trying to say is that you need to make it clear that there are two types of "grounding" for systems governed by the National Electric Code. First, your "tripping the breaker", "current returning to its source", etc issues are part of "Equipment Grounding". Second, draining charge from lightning and static electricity to the dirt is part of "System Grounding". Bill
I just read my above comment, and it's possible that someone might misinterpret what I meant by "draining charge from lightning". I'm not talking about a direct hit from lightning. I'm talking about lightning going from cloud to cloud overhead. That short, high voltage DC pulse of current will generate an expanding and contracting magnetic field. If your metal conduit, wires, etc are in that changing magnetic field, a voltage will be induced on those metal parts. The "System Ground" connection to earth (the dirt) is installed to drain that charge.
Thanks for clarifying. I thought that was a significant oversight in the video
Wow what a great explanation of the different ways that the N.E.C. establishes rules and regulations to protect the typical person. Keep up the good work. Remember to take out a permit from you local agency if you do any type of electrical work or upgrades in your home and only use qualified electricians to make the changes otherwise if there is a fire and it is traced to defective electrical work your home insurance may not cover the damages.
Thank you so so so much!!! You are an awesome instructor. I’ve been researching and talking to knowledgeable people about this particular subject without any understanding. You definitely have made it easy to understand. Thanks again.
Thanks for watching and commenting! I'm happy it was able to help.
This video really helped me understand how it all worked, this is good to know because if you mess up anything it will still be able to trip the breaker.
Thanks for watching and commenting! I glad it could help. The only questionable scenario is the last one where the ground impedance (earth) may not be sufficiently low enough to trip the overcurrent.
what a great video! the best explanation I have every seen.all the years I have been around electric systems There has never been information this clear . thank you.....
Thank you for the encouraging words!
Excellent video. I'd like to add that scenario #2 also takes place simultaneously in scenario #1 but imagine it's not shown for clarity. Once current hits the ground bar, it's going to flow in the neutral and ground return path and ultimately end up at the source. These paths run parallel from the bus bar to the meter and more current will flow in neutral path since it's likely made of copper vs the aluminum or steel raceway
Very well done explanation that simplifies the NEC Article 250 overall concept. Thanks !
Great presentation schuleuuuler. I am a retired journeyman electrician and I sure miss my trade!
Thank you for watching! A lot of days I miss the tools.
Thank you for your clear animated presentation that makes thing very clear and set up different real scenarios. Great job!
Thanks for watching and commenting!
Great video! I got my degree in Computer engineering, and feel very comfortable with electrical theory. But these kind of explanations, involving EMT, and power coming in from your power pole outside, are not often taught in school. They are the great to bring Electrical systems into reality.
Thanks!
Thanks for watching and commenting! I'm happy it was able to help.
I've moved back to grandpa's farm(Missouri, US) where all the electrical work was done by "touch it to see if its live" hillbillies. I knew nothing about ac so was confused and scared while working on it cause it didn't make sense. Now I know why. Neutral and ground are sometimes tied together at outlets, sometimes only hot and ground at outlets, all the breaker boxes have all the grounds and neutrals going to the bars with jumpers going to the box chassis, and the well only has 2 hot wires and no neutral OR ground. Your easy to understand explanation, the uncharacteristically salient remarks from RUclipsrs, and your polite and thoughtful replies(guess the Canadian stereotype is true) may have(probably) saved my ass from turning into a flash of light or worse... getting hung up on a hot that wouldn't trip the breaker and slow roasting. Pretty impressive for a RUclips, eh? I think I used "eh" correctly. 🤙
Lol. Thanks for the comment. You have definitely used "eh" correctly! Now go say sorry to someone for no reason, pound a bottle of pure Maple syrup and I'll make sure your official Canada touque goes in the mail.
I love farm jobs. Sometimes those old guys come up with the most effective, yet terrifying solutions.
Jacob Harmon
Yeppers, I worked on a 220VAC halogen light out at my in-laws, small desert town. I pulled the lamp, noted circuit breaker was off, aluminum ladder. The metal pole went hot. Luckily it was AC and I didn't fall, lost my breathe for a bit. Took a couple hours to find the problems. One was a missing ground.
On the main panel (first one after the meter) the neutrals and ground bars are bonded. Every sub panel after that the neutral and grounds are separated. The neutral bar connected to the neutral feeder wire from the main panel and the ground bar connected to the (usually #4 insulated ground wire) ground wire running back to the main panel connecting to the physical ground. I was recently working on a house where the wiring was quite old and I had to make sure all the metal boxes were grounded and the receptacles were grounded as well because the idiots who did the remodeling didn’t really know what they were doing. Tedious work.
Great video with explanation and working illustration makes it a lot easier to understand. Thanks.
Very informative, you answered my question in depth. Thanks! 👍
Sir I would like to say that all of your educational video is useful and easy to understand... Thank you for teaching 👍
Happy the videos are helping! Thanks for the support!
Great video, Thanks for explaining it step by step. The animation is awesome, it made it so easy to understand.
Thanks for watching and commenting! I'm happy it was able to help.
Super and easy to understand presentation. not those confusing Talkarounds right to the point
Thanks verry much
Chris Schmidt
Amazing graphics and quality explanation. Thanks for sharing.
Wow! Great graphic explanation. New to the channel. A graphic is worth a thousand words. You have a new subscriber
Thank you for making this video, it is well done and clear.
Thanks for watching and commenting!
Thank u so much about this whole explanation, hopefully u can post more about this based on the NEC, like gfci, afci, all different wiring system, that kind of stuff thanks again
I am looking at creating an animated walkthrough of a GFCI receptacle and how it works. Thanks for watching!
Your videos are amazing, its so easy to follow. You really helped me when I did Electrical Theory 1 last semester with the 3 wire Edison Video. Our books and instructors are good, but you explain a 1 hour concept in like 10 minutes which really helps when theres something we need help on.
Thank you for the encouraging comments!
Does this also apply to underground service cables? I have only a main panel in my garage and there is no grounding rod. Excellent presentation! Thank you for sharing.
New meter sockets have a separate lug for ground now and the panel bond screw would be green.
New to channel. Excellent video and graphics.
Best explaination Ive seen! Thanks for sharing!
Thanks! I appreciate that.
Splendidly Lucid. Deserves a subscription. Done!
Good and simple explanation. Got the guys into a good discussion about old mentality/perception thinking that the current goes thru ground and back to panel ! Like you videos, kind of like Mike ones. but it's about CEC witch is more for me :)
Superb video, clear, easy to understand explanation with animated diagram. I’m now a subscriber.
Thanks for the support!
Love ur presentation; I use the toast theory at work, the young guys love it:
Awesome! Always the most practical resistive load I can think of.
I asked my self why do you have only 13k subscribers....you do a big job and help a lot of students
Thank you for the encouragement! Always appreciated!
Excellent tutorial with superb graphics.
Thank you for the encouraging words!
one of the best teachers at SAIT.
Thank you my friend. I appreciate the encouragement.
Outstanding explanation. Thanks.
Thank you for the explanation on grounding and bonding.
You are welcome! Thank you for watching!
Excellent video and explanation. Thank you.
Thanks for watching and commenting!
Mr. SchulerRuler, you have made an EXCELLENT video! Your animated diagram is an excellent visual tool that allows the viewer / student to 'see' the electrons, which is what understanding electricity is all about.
However, I do wish you kept the yellow short-circuit path on the screen longer, and speak to it more, so the viewer has more time to absorb it; you take it away quickly.
I have subscribed and look forward to seeing more of your videos!
Thanks for the video, well done! Still confused on one thing though. If the meter and main panel both have the neutral bonded to the case/ground, would that cause objectionable current on the ground wire or metal conduit anytime there is normal current flow through the neutral? Being that there is a parallel path from the panel to the meter it seems as there would be. Just like if a sub panel was had the neutral and ground bar bonded together there would always be current flowing on the ground when there is current flowing on the neutral back to the main which would be a problem. Why is it not a problem when it’s flowing on the ground from the main panel to meter? Or am i just misunderstanding something?
Great video, I have a 65yr old panal that I have to use a generator on while new 100amp service is installed. I second guessed myself for a minute, should work ok.
Beautiful demonstration.
Nice! Kratos taught me electrical topic more than school.
Great graphic, excellent explanation.
That was a great video. Really clear and informative.
Thank you! I'm happy it was helpful for you.
Good video nicely made and looking at the comments it has surely brought some intellect's here to discuss their knowledge
Thanks for watching and commenting! Some very good points have been made, and some good discussions too!
Thank you! Nicely explained!
Thanks for watching and commenting! I'm happy it was able to help.
best I've seen so far.
Thanks, I appreciate that.
@Mister Brookes Please keep in mind this is not a US video and other locations require less than 5ohms, as opposed to 25.
Also it is dependant upon the soil conductivity, moisture content and saline content. You are also assuming all services are 120v. If you are going to apply some ohms law for calculation purposes, don't forget about 480v and 600v services as well.
The NFPA or IEEE? Both state resistance to ground should be less than five ohms. The NEC states less than 25, and less than 5 for buildings with sensitive equipment.
Mr brooks, unless I misunderstand your comment are you saying that paralleling two rods would increase the resistance higher than 25 ohms? Adding the second rod would decrease the total resistance bringing it below 25 ohms, which is why the NEC requires the second rod. As an aside, Some localities will require a second rod in situations where a building does not have any code permitted electrodes, such as a garage where there is no water main, foundation rebar or building steel. This of course has no bearing on the original subject matter.
I removed some old (unused) knob and tube wiring from my garage. Although there was no equipment ground conductor or raceway conductor, the neutral wire was much heavier than the hot wire. The hot wire was I think 10AWG and the neutral was 8 AWG. Was this their way of doing what you say about creating a low impedance path to ground?
thanks man. The visuals were great
Thanks for watching and commenting!
Great explanations thank you very much...
Thanks for watching! Hope it helps.
Thanks for this info sir, I have only one question, assuming the grounding wire from the panel disconnected (the grounding wire going to ground rod), will still be tripped the breaker if the load's body touched to the hot wire or live wire? If someone touched the body of the load which touched the hot wire, will not he or she be electrically shock because someone touched a hot wire and he or she is grounded, he or she will become a load of the circuit.
Thank you sir.
Great explanation Sir. Thanks
Thanks for watching and commenting!
awesome video Chris!! Ya toast!
Thank you. Good video.
Great info: I have a question? on a short . net. to power....will the main breaker only trip when the current exceeds the main breaker amps? it will only trip the load breaker if short only exceeds the load circuit amps?
A standard thermal magnetic breaker will trip from a short circuit current, meaning line to ground or line to line due to very low impedance causing a strong enough electromagnet in the breaker to pull open the trip coil.
In an overload condition, meaning higher than regular current but far less than short circuit (say 18 amps on a 15amp breaker) the higher current will cause excessive heat inside the breaker (resistor or simar device) that will cause a bimetallic strip to bend and actuate the trip latch.
Not sure if this answers your question or not.
Nice simple explanation
Excelent video, one question: if an isolated solar inverter has voltage between neutro and ground can I bond neutro and ground to eliminate de neutro voltage? Thanks a lot.
jose olavarria you inverter is a source of power like a generator and should be bonded at the first means of disconnect/ over current protection
The neutral buss or terminal in the solar service disconnect should be bonded to ground. If you have significant voltage between neutral and ground, then your neutral is not bonded at the main service disconnect or possibly the bonding path is broken somewhere.
That made a lot of sense, thanks
Love the visual 👍🏼
Thanks for watching!
Great video. Thanks
Thank you... Most helpful !
Thanks for watching and commenting!
wow thank u so much for this video
Excellent presentation. Should be mandatory viewing for everyone working in
this field. Question, I see step down transformers where that units earth ground is either broken or missing, taken for whatever reason. So it would seem
that in the event OF AN OPEN NEUTRAL back to the transformer, the EMERGENCY back up would not work. RESULT HOT NEUTRAL toward the
transformer. Your thought please. thank you.
Great video. Very helpful!!!!!!!
Genius. May you make a video teaching how to wiring a lighting contactor? Thank you for share your knowledge.
Hi! I understood everything you said except the last part. You said the current doesn't go to ground but rather finds its way to the system ground, travels back, and then trips the breaker.
I'm not sure if this is true. But if it were, how far away can that current travel to find that system ground at the transformer?
Same Q. You said, it travels through the dirt and finds a path back to the other grounding electrode. If it did, would this not involve a great deal more resistance--inhibiting current flow and preventing the breaker from tripping?
If there was enough current to find the ground in the transformer and then trip the breaker all the kittens and dogs and people walking barefoot between the house and the transformer would get toasted the same way the bread was about to get toasted. This makes no sense.
The center tap of the utility transformer is not grounded, the core is. That is why the return path has to be through the neutral conductor. Grounding the return current will not clear the fault because the impedance is too high.
Excellent teaching. could you explain when the main ground to the panel get disconnected at 115v outlets can read 220v
Thanks for watching and commenting!
If the reference to ground is removed at your neutral point, or if the neutral is broken, your supply voltage (240v) will distribute proportionally amongst the loads. Higher impedance loads will have higher voltage drops while lower voltage loads will have smaller voltage drops. At this point we have to think of the circuit as a 240v supplied series circuit as opposed to 120v individual circuits. The grounded reference was what maintained the 120v.
Check out my channel as one of the latest videos I've uploaded deals with open neutral situations in an unbalanced Edison three wire distribution.
This is excellent. Thank you
Thank you for the support!
Great explanation. Thank you
Thanks for watching!
Very good explained
Thanks for watching! Hope it helps.
Thanks for sharing. I have a pull out breaker next to the service box meter box. the main box is inside the house without a ground but the metal tube from the meter box to the main panel is wraped around with a ground but it never is attached to the ground bar. Should a ground be attached to the ground bar in this situration?
Thank you for the video - very helpful. @7:30 wouldn’t dirt provide a decent amount of impedance depending on the distance of the two grounding rods? If that we’e the case, the current would never be too high and the breaker would never trip. What am I missing? Thanks!
It is highly unlikely the breaker would trip in that scenario, and also very unlikely a situation like this would occur, as there would need to be many points of failure before getting to that. Though i would like to see dtudies from an area with a higher moisture content, or closer to seal level to find out for sure.
Thanks for watching!
Flash pan you are correct. If you were to connect a wire from a circuit breaker to a ground rod, that breaker would not trip. I’ve tried it.The impedance is too high, enough current will not flow.
Awesome, well explained.
great presentation, thanks
Thanks for the encouraging words!
Great! Thank you! Plez tell me what happened remove earth wire in db board
Hi, great video. Explains quite a bit. Question - why do we remove the bond screw in a sub panel situation?
Thanks for watching and commenting! If the brass screw were not removed it would create a parallel path back to the supply neutral via anything bonded. It creates touch potential on metal components and this is not a situation that would trip a fuse or breaker. A GFCI would most likely trip, as there is a differential in current out to load and back on identified neutral.
If this situation were to occur, someone touching metal (ie conduits, boxes etc) would then be at the same potential as the bonded metal and could recieve a shock by touching something grounded. Not ground itself, but something connected back to the supply grounded (neutral) connection. You would be essentially completing the path.
schulerruler - thanks for explaining.
Really good and interesting
Thanks for watching and commenting!
Thanks for the presentation, but I'm unsure if this is code compliance because the bonding conductor was not addressed here? so how the fault current will travel through the natural conductor ? or grounding conductor for the branch circuit, you provided only grounding but no bonding.
Great teacher, very nice 👍
As well.....if the short is grounded by a ground wire that goes to the ground bar in panel and goes into the ground via ground rod and system neutral grounding. If the metal boxing, panels, metal raceways, etc are bonded to ground, yes they are energized too by the short but are safely carried away to grounding mechanisms. All this to protect YOU from becoming a big resistor going to ground.
how do i know if my gas csst piping is bonded? Im looking at the icc evaluation notes on this and it says its considered bonded if "connected to the equipment grounding conductor of the circuit supplying that appliance." so does this mean that there's an extra piece required..the csst is not just coming from the floor and connected to the appliance gas connection?
Perfect example of why neutral in ground are hooked together with the bonding screw so the breaker will trip when there's a short circuit to ground if not ground will become hot because of the resistance to Earth ground
Great Video, thank you indeed, also would have a quick question, would you please let me know, how a metal conduit will be grounded if it is used for mechanical protection? is it grounded at one end? or two ends? the same question for the shield of the cables, do they need to be gronded at both ends? is there any certain rules to determine when the ground loop could be occurred and not to ground at both end? (for instance, communication cable/ control cable/power cable ..) thank you in advance for
Generally the connections in couplings and connectors are what create bonding continuity.
Single conductor cables generally have only one side (commonly the supply) bonded to eliminate the flow of sheath currents.
This is interesting and informative video but I haven't seen many if any residential services with a full all metal configuration, they're mostly PVC and romex with plastic boxes. I'd like to see that representation.
Great video, just one question...What's a Conductor?
In this case, a wire. Generally, anything that conducts electricity.
Hi Schulerruler, thanks for the detailed explanation, I have one dumb question though! if the netral and ground wires are connected at the panel, In a normal no fault condition if the return current is making its way back to the main panel via the neutral wire and once it reaches the bus bar where it bonds with Ground wire, why will the current not flow back via the ground wire into the connected metal devices body(eg: say back to a washing machine's metal body inside the home connected to Ground wire)? how does it always flow back to the center tap of the supply transformer?
It wants to return to its source due to potential difference at the source. Through the metal components there is not a return path to supply source, but the neutral is a return path, which completes the circuit
@@schulerruler Thanks a lot for taking time to explain, now I understood.
Great video! Thanks. But is there a difference if the fault is on the neutral, after the load?
A fault in the neutral can mean two things, a short or an open. In the case it is a short to ground, nothing would happen as far as breakers tripping because the neutral is already bonded to ground. If the fault is an open, then there is no complete path for current from from the load back to the source and so the toaster in this scenario would turn off.
@@ryndroma So you're saying that if a neutral, in a 4-square box, comes in contact with the side of the box, after the load, nothing will happen?
That's correct. In a solidly grounded system as mentioned above, the neutral and all metal components are effectively the same point, so it's like you hung the wire to itself.
The identified (what we commonly call neutral) and metal box are at the same potential. This is done deliberately at the service disconnect, or meter base (one or the other) to create an equipotential between them. It is what provides the low impedance path to facilitate the operation of overcurrent devices.
Remember, past the service disconnect, the neutral or identified is absolutely isolated and not permitted to intentionally contact anything metal.
This would not trip an AFCI but most certainly would trip a GFCI as an alternative path would carry normal operating current back and create the necessary differential in current between the identified and hot conductor.
This is not a dangerous scenario, because as mentioned, the identified conductor and square box are already at the same potential. No potential difference between them means no sparks.
The issue that arrives from inadvertent contact between identified conductors and metal past the service disconnect is now you have objectionable current flow as a parallel path back on metal components, this the reason for neutral and identified isolation. Long story short, don't connect the white wire to metal. As electricians we are trained to know this and not do it.
What size wire would be best for grounding a residential circuit break box?
The grounding electrode conductor is sized per the NEC based on the rating of the service disconnecting means (main breaker or fuse). It would be #8 copper for 100 amps and #4 for 200 amps. The grounding conductor to the supplemental rod never has to be larger than #6, although it can be #8 for a 100 amp service. But #8 would need to be protected from physical injury.
If I use a bonded ground Gen is a ground rod ok? Have 2 100s and nutrual to box. Thanks
Good job
Thanks for watching and commenting!
Question: Service raceway is made of metal and is in contact with the panel. Say, if I don’t have both the neutral wire and service raceway bonding jumper I will still have return path to transformer neutral. The fault current will flow through the panel -> service raceway -> Meter Neutral Screw terminal -> back to transformer neutral. Is this correct ?
If your meter base is the point where the neutral is bonded to the system, then yes, you are correct.
Very well said. Thank you
Thank you for the encouraging words!
Do you have a video explaining grounding electrodes and why or why not they're necessary?
THANK YOU ! i GOT IT ! What would you think of running a buried ground wire back to the utility pole ground ?
It would provide an alternate path back to the supply transformer, but would there be a potential for transient lightning voltage on residential systems if a power line was struck?
There would also always be a current flow through that conductor as it would now essentially be a neutral parallel path.
I am with shuelenruler on this one. Many reasons not to do this.
Nice explanation.