Ground Rods at Metal Poles, NEC 2020 - [250.4(A)(5)], (25min:09sec)
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- čas přidán 28. 06. 2024
- Is a ground rod required at a metal light pole? Join Mike and the team as he discusses why a ground rod doesn’t protect you from electric shock hazards, why you need an equipment grounding conductor, and why ground rods don’t protect pole lights from lightning.
This video is extracted from Mike Holt's 2020 Understanding the National Electrical Code Complete Library, for more information visit www.MikeHolt.com/code or call 888.632.2633.
For over 45 years, Mike Holt Enterprises has been providing quality electrical code training to help electrical professionals learn the code, prepare for exams, and improve their electrical knowledge. Visit www.MikeHolt.com for exam preparation tips and training, instructor and curriculum support, continuing education options, free videos and graphics, and so much more.
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Mike. Shared this video with guys at work. You have created a learning environment and discussion. Your video has helped us all understand the difference between BONDING and Grounding.
Great video , I am a retired maintenance electrician and Love watching these videos . Thank you .
Hello Mike. My Dad told me of a lightning problem they had at the Timken company at their Bruster plant. Lightning would hit the chain link fence, travel down the fence, jump across the opening at the main gate, into the guard booth on the other side and hit a water well casing that was inside the booth. He said they drove and connected ground rods next to each fence post and this helped but didn't completely solve the problem. They finally replaced all of the fence posts with very long post.
Interesting.
Fantastic video. I actually stumbled on it while I was meticulously going through your book. I had more questions about the voltage gradient && contact resistance of ground rods (seeking clarification) and found your video. Thank god! Because I actually think that one job I was on, the foreman had us skip the grounding of the parking light poles, saying "we'll just drive ground rods at each pole". As an apprentice, I know for a fact I'll be pissing off some journeyman foreman by telling him we're doing this wrong if he chooses to install ground rods in place of an effective ground fault current path. Thanks Mike! Love your books. You're literally saving people.
It's unfortunate that in our industry we can['t have adult conversations about this type of thing. Everyone is more worried about being in command than being correct. We are changing over a hundrted years of "tradition" in our industry. Thank you for taking the time to become educated and sharing that with others.
I think some of the problem is people think they have to do this for 'lightning' safety. There seems to be a lack of understanding that lightning protection is its whole other ballgame and a single ground rod isn't going to protect anything or anyone.
Exactly...
Thank you for sharing your knowledge.
I wish more electrical engineers around here would watch this video. Every new construction job i have bid and done has ground rods shown in the drawings at the poles
i think wire fences post for livestock fields are recommended to be connected to ground electrode for lightning protection as per NFPA 780 Standard for the installation of lighting protection
Great video Mike! Thanks for sharing.
Should only be refered to as a short circuit path, not ground fault. Unless it is a stray voltage scenario in which some voltage is seeking ground or gfci.
But as far as a ground fault path it truly is a short circuit path
I was working for a lightning contractor and we had a bunch of small light pole/mail boxes in an hoa. The mail person stopped delivering mail because they were getting shocked. The light poles were fed from buried rmc conduit that was rotted away with no egc. I was belittled because my suggested fix was to replace all the conduit and install a egc. Boss sent someone else out to drive ground rods😕
This doesn't surprise me. Many electricians are obsessed with worthless ground rods. I hate how stupid some electricians are.
@@crissd8283 Not just the electricians plenty of other trades and inspectors with little to no electrical know-how obsessed also!
Your story is one of many. We have to keep educationg those that will listen. Eventually all of the "Electrosaurs" will be extinct and we won't have these issues.
Thanks Mike love your content
Seen lightning hit communication tower with 3 4/0 ground wires going to ground field. Even the guy wires that were hooked to ground field smoke. To protect from lightning is very difficult the only thing that helps is the whole thing went high at one time if that's the right terminology. So minimal damage took place
Thanks Mike very useful
Got You, Mike. I always was aware that most electricians don’t understand the Main Concept of Earth : equal amount of positive and negative in the Earth and as far as we know in Universe. If you intend to get the Deamons throughout this turmoil: Them gonna break loose
Thanks, Mike for all your input
I am an electrician and musician
For 20 years
I had a 277 parking lot 20 amp breaker pulling 45amps on the circuit.
Thankfully nobody died.
Wow.
That why when I work on any pole I check it with ncv meter to the metal to see if it is energized
It's very dangerous when people THINK they know how to do something but really don't.
Thanks for the video very good content. What I found is It’s not an NEC requirement but it’s in the NECA NEIS 501 Standard for installing Exterior Lighting Systems
I call this 'dinosaur do do.' Next time I speak with Mike Johnson (NECA), I'll let him know that it should be removed. Thanks
Just shared this with several of my graduates as a reminder.
Thank you!
It's scary how inspectors here in Nova Scotia require ground rods connected to outdoor event stages... so you have a fault to the stage structure the whole stage becomes live! If a ground rod can't be driven and the stage is adjacent to a large body of water like the ocean or lake they have us throw a ground plate or rod in the water. Scary stuff!!!
Going to literally get killer voltage gradient in fresh water
I have heard nightmare electrical situations in this industry. You just added a couple more. I am happy I don't frequent concerts and outdoor events.
You said in this video that the portable generator did not need a ground rod but if your generator is a bonded neutral generator and providing back up power to a residential house with a switched neutral transfer switch you would then need a ground rod.
Ground rods serve two purposes. 1. To attempt to bring the EGC/metal/neutral to the potential of the local Earth. 2. Provide a path to Earth for lightning. It is not a means to trip circuit breakers.
Mike, learning a lot watching your videos. Question: would the ground rod work to clear the fault on a pole carrying high voltage power lines (i.e. voltage greater than 25,000 volts)? Thanks for your thoughts
I see towers with antenna arrays everywhere with grounding electrodes and their respective conductors at the base. Sometimes up to four or more. Cell tower sites have grounding electrodes everywhere with every metal piece of equipment tied together. Maybe it’s only to prevent a difference of potential for worker safety while in the site area. I’ve seen similar sites where the grounding electrode conductors appear to have been purposely removed but still present. I wonder if they have something to do with the radio frequency and it’s proper propagation. There is a mono pole antenna tower I’m familiar with that the terminations are loose enough you can rotate them around by hand.
Nice video!😆
🥃🥃🍺🍺🍺🎯🏌🏻♀️
Mike. I'd like to hear your thoughts about grounding drums and containers of flammable liquids and storage cabinets for flammable liquids for protection from fires that could be caused from a static spark?
That is a totally different concept and there are NFPA standards that address this issue, particularly NFPA 30, Flammable and Combustible Liquids Code.
@@MikeHoltNEC Thanks.
This reminds me of a argument amongst technicians when i used to install burglar alarms for ADT. 16.5 vac. Transform did not have a grounding conductor. ADT requires we ground the panel. We argued that grounding the panel only made a path for lighting through the panel to the ground. Lighting strikes would often run current through the alarm wires into the panel if it was grounded. Without grounding the panel, the current found a different path. What are your thoughts on this?
The very remote chance that lightning would strike the building vs the possibility of static buildup shocking customers touching the panel or causing interference with electronics. That's my understanding at least
Watch this video on why you should NOT ground the fire alarm panel to the earth. czcams.com/video/WlnFNTay-9Q/video.html
Some jerk really messed people's heads up by saying "electricity wants to go to ground."
Are there any issues installing auxiliary electrodes in addition to having an EGC? The reason I ask is for ground mounted solar array the inspectors always want ground rods installed. Of course we are still running an EGC in addition to the ground rods.
I have a problem with this practice, watch czcams.com/video/WlnFNTay-9Q/video.html and czcams.com/video/Ypo99VRxT44/video.html
Would calling it an equipment bonding jumper be used to clear up confusion?
Hahahaha that example of the fence with the ground rod kills me.
Mike your energizing the ground if the sprinklers were on you'd really get cooked
Love the show Mike I've learned so much here thank you man
Mike, you're making a lot sense as usually.
Isn't a concrete slab like an electrode?
So why do they try to ground a post bonded to a concrete slab?
I don't understand your comment. See czcams.com/video/mpgAVE4UwFw/video.html
If a lightning strikes a pole with effective ground fault current path, what will happen to the cable ensuring effective ground fault path from pole to source. How should we size that cable to ensure the damage don't happen to the cable. What should be the minimum size of that cable considering lightning?
The National Electrical Code is not a standard that has anything to do with lightning. If lightning struck a pole, then everything that was damaged needs to be simply replaced. Nothing you can do about this, except to provide lightning protection system per NFPA 780 for the pole. Of course that would make no sense.
In your view, do outdoor metal poles with only POE devices (WAPs/Cameras) fed from building require an EGC? I've watched the entire video and reviewed the code but I can't find a clear answer. Is the pole "likely to be energized" by POE fault? By the letter of the Article 100 definition of "energized", the answer is yes. So do you run a dedicated EGC from the building telecom/electrical ground bar to the pole?
This is a very tricky subject. The wire bonded to the light pole metal structure providing the fault current return path should theoretically be at ground(0v) voltage. However in practice this may not be the case and again lead to electrocution. Tricky indeed!
The earth will be zero volts related to the phase conductors, but that is irrelevent. Please watch my video MikeHolt.com/Fundamentals.
Do you have to ground a roof mounted over the air TV antenna? If you do, do you have to ground it near the main panel existing grounding, or can you ground it near where that antenna is separately?
Please watch this video for your answer.
@@MikeHoltNEC I always watch videos before I comment. So either I’m not getting it, or it’s not covered.
@@bob847vid I understand, please watch this video and let me know if you now 'get it.' czcams.com/video/mpgAVE4UwFw/video.html
@@MikeHoltNEC so following the video which I watched before but watched again thinking about this particular application, I’m assuming we treat the TV antenna like a solar array on the roof. In that case no separate earth grounding rod should be installed. I still don’t know if a the antenna mast or coax cable shielding should be attached to any grounding though? Should
It run to the existing grounding rod at the service panel?
@@bob847vid This video is about why the grounding of a metal pole serves no purpose and that we need an equipment grounding conductor to the metal pole to clear a ground fault. Questions related to TV and satilite antennas - Watch czcams.com/video/cwB9xd-CzTU/video.html, questions related to Solar - watch czcams.com/video/NkDYphpg8sM/video.html and czcams.com/video/Ypo99VRxT44/video.html
What is the implication for grounding rods at sub-panels that have equipment grounding conductors to the main panel? Thanks
It doesn’t have to be a grounding rod, any kind of GE(grounding electrode) will work as the one required by the NEC at remote buildings with electric power.It has the same purpose than the one at the service and is among other things to bleed out any kind of induced and dangerous voltages preventing arching fires,damage of equipments and electrocution by voltage accumulation on metal parts.
No that is not the reason - watch czcams.com/video/mpgAVE4UwFw/video.html
You my friend are 100% correct!
@@MikeHoltNEC Why does the code keep changing on grounding electrode separate buildings isolated groundlng conductor versus Grounded Conductor Bonded as a main panel. 2 ungrounded conductors one grounded conductor. Versus 2 ungrounded conductors and one grounded conductor and one Isolated grounding conductor bonded to the grounding electrode? When the utility provider loses its ground from the transformers you’ve got problems either way.Potential difference in grounds becomes apparent water pipes always Stray voltage
@@danielsullivan9865 I have no clue what you just said. There have not been any NEC changes on the practice of 'grounding' for at least the past fifty years I'v been in the electrical trade.
What’s the reason for all the ground rods and ground ring on cell towers. All the ones I inspected were pretty much design the same way
That type of grounding has nothing to do with the National Electrical Code. It's purpose is to reduce the difference of potential between metal parts in the even of an lightning strike.
@@MikeHoltNEC I thought it had to do with noise and interference with signals
@@danielsullivan9865 What do you think 'noise' is? Grounding of a cell tower system has nothing to do with reducing the interference of the signal. It simply is a way to reduce the difference of potential between the metal parts of the cell tower to the earth. If you get any documentation otherwise, please share it with me.
Hi Mike. I was wondering if the provenance of your name is Overholtzer. You kind of remind me of that side of my family. Thanks. Great video, as always.
...lol... maybe!
Mike I have questions ! Don't we all say that the earth is neutral or it's zero? And if you hit the hot wire with neutral will trip the breaker? So "If we hit the hot wire to ground rode will trip the breaker "?
Why it didn't trip in your live example?
Everything you said is 100% false, please watch czcams.com/video/mpgAVE4UwFw/video.html
Electricity travels back to the source. When you connect the hot wire to neutral it sends a very large amount of current through the circuit back to the source tripping the breaker
@@nicnac2400 Why would you connect a hot wire to the neutral? What does your statement have to do with the silly practice of grounding a metal pole to the earth (when it's already connected to the earth via the metal bolts)?
So your saying the neural is all you need in your home? Code just made me put 2 ground rods over 6 foot apart s house I'm restoring bonded with the neutral
The video is about a ground rod at a pole, not a home. Please watch this video - MikeHolt.com/Fundamentals.
With that video of you putting in that ground rod and the generator, what would you have to do to get hurt. Why didn't you get shocked when you touched the metal of the equipment
I don't know what video you are describing.
How to protect a light pole from lightning - replace as necessary.
?
Can FMC used in old house consider as effective ground fault current path?
Read 250.118 and let me know what it says please.
@@MikeHoltNEC yes I read the article. OCPD should be less than. 20 A. But 250.118 5 d got me confused. It said combing length of conduict not exceed 6 feet. So that mean FMC used in old house ran mor than 6 feet are not consider as effective ground fault current path?
@@benzaguru4548 If the NEC says a maximum of six feet, then clearly anything more is a violation. What about this is confusing?
@@MikeHoltNECthanku. not any more. That's why we need seperate equipment grounding conductor in FMC that used in old house. All those FMC are ran longer than 6 feet. So we can not use three prong receptacle without seperate equipment ground conductor.
@@benzaguru4548 You my friend are sounding like a Code expert. Congratulations. But when replacing receptacle, they don't need an EGC, see 406.4 on the rules for replacing receptacles, and the GFCI option.
I think mike knows Joe “ a buddy of mine” Rogan
Sir, how can I get the books and the price?
Call our office at 888.632.2633, they will take care of you and get you the best price. Thanks, we look forward to helping you!
Really love the content of the videos it’s excellent.
But the room Echo picked up by the microphone is so much trying to listen to the video on a phone in a mobile location makes it inAudible .
Turning up the sound to maximum sound volume just trying to listen to the word content with any background noise in the listeners area still cannot pick up all the words meaning in contacts.
Still great content listen to all your videos just have to go home and listen to this one in a dead silent room on a larger speaker system
I messed up the audio (dead battery), so I had to go with what I had. Sorry,.
Could ground rods at light poles help protect from lighting strikes affecting poles down stream? It would obviously not stop it in its tracks but with the high impedance down stream for the electrical system for the high energy pulse of lighting i would imagine it would at least have a chance at saving down stream light poles.
Nope. When lightning hits the first pole, it simply destroys the light fixture, and not likely to damage the copper wire to the fixture. So it's not going to damage the wire to different pole.
Do some research, on conductor, transmission of Energy "WAVES", it is not moving of electrons, inside of wire, its the field surrounding, of conductor, that moves Power. Lightning is air gap, field power, yes that ground rod is required, of 30ft larger metal poles, as in traffic light standards, I Installed a "LOT", of em.
First part of your statement is Correct . This video proves it...
czcams.com/video/bHIhgxav9LY/video.html
Are you saying that we need a ground rod at a metal pole for the electric energy to get to the light for it to illuminate? Are you an electrician in the US?
Are you saying that we need a ground rod at a metal pole for the electric energy to get to the light for it to illuminate? Are you an electrician?
Shouldn't it be bond fault then?
Yea... but the NEC uses the term 'ground fault' so we are stuck with that term.
@@MikeHoltNEC what would be the right denomination? Neutral bonding mass fault or something of the sort?
@@0786RICARDO Since all my work is related to the National Electrical Code, the proper term is 'ground fault' in accordance with Article 100 Definitions.
Great job Mike... I hope these ''old'' engineers wake up...
They are dinosaurs, we'll need to wait until they and others move one...
@@MikeHoltNEC , thank you Mike, your knowledge is so valuable and yet, people watch your content and do not fight back... Perhaps, the contract specs do call for those ''details'' but, the contractor could push liability back -- simple, reference the ''unsafe condition'' and ask for another review addressing the ''path'' that may be created by using this ''extra bonding''...
Mike, I recall your video; the water and the military guy... it was interesting...
I recall, turning on water and putting an electrical meter in the ''hot leg'' and the the leg in the water flow... yes, I was able to get a volt reading (of course)...
Again, thank you for your eduction.
Add ground rods to provide shortest paths to Earth from conduit that goes to the roof or to poles or elevated antennas. You want lightning to form plasma paths to the Earth. You don’t want lightning wrapping around the house or traveling through your house. Call these lightning grounds if you wish. Extra ground for motors or whatever not required by NEC are absurd.
I believe “Mythbusters” tried the male dog thing, except it was a person and the third rail of a subway. Could get it to happen.
That episode has nothing related to the discussion of opening the circuit protection device by using the earth.
If lightning hits a pole with a ground rod it will glass the rod making it unaffective in the future.
That is possible - www.rakov.ece.ufl.edu/Gas.html
Dr Phil? Is that you?
Lol....
It’s in the architectural drawings, engineer asks for those stupid ass ground rods on those light poles or near machinery.
Yes, but some inspectors require even if not on the plans and others require the plans to include this design. How sad...
Gonna step out on a limb here. Taking the lighting's perspective, i imagine it's goal in life is to connect the clouds to the dirt. If that involves a tree, the aerial service of a building, the ground rod at the utility pole, the ground rod at the service, a building's wiring or plumbing, or whatever else is conductive enough to get the job done, it will use. Of course the rebar, the threaded studs, and concrete of a pole light's base functions as a sort of concrete encased electrode. So, I'm guessing here, the auxiliary ground rod MIGHT(purely hypothetical here) help prevent the circuit conductors from getting fried when lightning hits the pole.
Of course our goal is not to help lightning get to the earth... Also a metal pole is already in the earth and doesn't need any additional grounding, but remember grounding is not needed in the first place. See czcams.com/video/mpgAVE4UwFw/video.html
the grounding is that it is not really taught anywhere even in university
I know, please watch czcams.com/video/mpgAVE4UwFw/video.html
It seems to me that installing a ground rod at a sub panel in a shed is begging for a lighting strike at a nearby tree to travel from the tree roots,to the ground rod, to the equipment grounding conductor in the sub panel, bringing it to the main service panel in the house. WHY ?
What purpose is it serving at the shed?
Probably, the reason the designers and contractors spec and use ground rods at these locations are LAWYERS.
Please watch this video - czcams.com/video/mpgAVE4UwFw/video.html
great presentation. lol solar DC systems are much easier it is much more difficult to design and implement AC systems. I remember designing a synchronous generator for a power station that was my most difficult class in electrical engineering in college
What, you watch a video about ground rods and you don't think I'm that smart to do Solar? When you get a chance, visit MikeHolt.com/Solar, it contains the books and videos that I produced on this topic...
@@MikeHoltNEC sorry I mistyped. I was not talking about you specifically. I was really saying AC systems are much difficult than DC solar systems
@@MikeHoltNEC I learned all my grounding know from you actually
11:32 is literally the dumbest thing I’ve ever seen. 🤣
The sad thing is that this is 'reality.'
mike thats a globe ????????????????
?
I'm going to assume that you've never been in Coral Gables or Florida period. It's sand....
What is your point? By the way, I went to Miami High and attended UM in coral gables.
@@mikeholt9781 watch and listen to what you said.
A post driver was in the picture.
That was not in Coral Gables, that was in Kendal.
Ground rods are for the grid not your safety.
This is a metal pole, there is no requirement to ground the pole, and there is not requirement to ground the 'grid.' What the heck is a 'grid?' Please watch this video - MikeHolt.com/Fundamentals.
@@MikeHoltNEC what’s the point of a ground rod ? It’s not to keep you safe and it doesn’t disperse enough energy to make a bit of difference on a home that has a surge. Now if you have a couple hundred grounding rods on the homes connected to the the POWER GRID !!! It will make a difference it’s only to protect the power grid. So if you think you need an extra grounding rod on your home you better call an electrician that knows wth he’s talking about to find the lose or broken common or ground that’s causing your appliance to become electrified. Let’s see why would they want or need a grounded metal pole on their grid ? Hmm 🤔 probably because they need it to divert a surge.
@@slickruler2336 Grounding of the metal pole does not assist in diverting a surge, whatever that means. Please watch MikeHolt.com/Fundamentals