I had a customer just last week get upset with me that I did not connect his new Generac generator to the ground rod he drove beside it. I tried to explain this very point but I don't believe he understood it. What are the odds this video comes out a few days later! Thanks for another great explanation of the code!
Yes, the adding a ground rod near the equipment originated with trying to mitigate noise issues in a poorly laid out system. When these high speed electronics hit the market, and all the high speed switching and harmonics thereof, was a new animal and there was little understanding of them at first. Hopefully we have since learned more about them and understand them a little better.. Well hopefully..... :)
In the video you discussed how you thought that the auxiliary electrode was not a good idea for the generator example but I was hoping you would expound this to the light pole as its very common requirement for an auxiliary electrode to be driven at a light pole especially when there is also lightning protection on the light pole. So does an auxiliary ground at light poles help or is the same as the generator example, it causes more problems? This has been an ongoing debate about how to keep the surge from a lightning strike on light poles from getting back to the electrical panel feeding the light poles. Any advice here?
Thanks Mike, that is what I was thinking was going to be the answer. May not save the pole that gets the direct strike but at least minimize the damage to equipment inside.
@@mikewhitlock1849 Great question, no. Why not? Because if you follow the lightning surge current between the two electrodes, there is no electronic equipment in the path. Also the NEC requires an electrode at the service [250.24(A)] and at a remote building [250.32(A)] to accommodate both system grounding [250.4(A)(1) and equipment grounding [250.4(A)(2)].
So if the outdoor electrical equipment sets an Auxiliary Grounding Rod, a good additional design is also setting an SPD at the Pannel, to protect the EDS inside the building. SPD should based on the 10/350 test wave.
Surge protection in this example would not make a difference from the induced current from the lighting. SPD are always a good idea. Please watch the entire video, not just the short. Click on the link embedded on the bottom of the short.
Not needed as per code is similar to the EIA/TIA standards that restrict pipe bends to 180 degrees and disallow conduit bodies for communication cables. We had to follow specs on equipment with electronics. Installed them per specs, did not violate code, got paid, went home.
But what about a bonded neurtral generator with gfci? Wouldn't that need a three pole transfer switch to switch both hot legs and your neutral therefore your generator would need its own electrode system correct?
Mike what about lightning supresion systems and more then one grounds that are not connected. My first asumption is never connect this to the main panel ground.
![Grounding, System and Equipment [250.4, 2020 NEC]](http://i.ytimg.com/vi/lyD6gzEze68/mqdefault.jpg)
![Grounding, System and Equipment [250.4, 2020 NEC]](/img/tr.png)
![Grounding, Auxiliary Grounding Electrode [250.54, 2020 NEC]](http://i.ytimg.com/vi/gg4wBI7bWgI/mqdefault.jpg)
I had a customer just last week get upset with me that I did not connect his new Generac generator to the ground rod he drove beside it. I tried to explain this very point but I don't believe he understood it. What are the odds this video comes out a few days later! Thanks for another great explanation of the code!
You are most welcome.
I like superfluous better because it really puts a pin in how unnecessary it is.
Yes, the adding a ground rod near the equipment originated with trying to mitigate noise issues in a poorly laid out system. When these high speed electronics hit the market, and all the high speed switching and harmonics thereof, was a new animal and there was little understanding of them at first. Hopefully we have since learned more about them and understand them a little better.. Well hopefully..... :)
Excellent comment.
In the video you discussed how you thought that the auxiliary electrode was not a good idea for the generator example but I was hoping you would expound this to the light pole as its very common requirement for an auxiliary electrode to be driven at a light pole especially when there is also lightning protection on the light pole. So does an auxiliary ground at light poles help or is the same as the generator example, it causes more problems? This has been an ongoing debate about how to keep the surge from a lightning strike on light poles from getting back to the electrical panel feeding the light poles. Any advice here?
Driving a rod or not will not reduce any surge backfed current. But maybe having SPD on the circuits to the outside pole lights would be helpful.
Thanks Mike, that is what I was thinking was going to be the answer. May not save the pole that gets the direct strike but at least minimize the damage to equipment inside.
@@jeffl3506 a ground rod serves 'no' purpose at a metal light pole and doesn't protect the wiring inside the metal pole (Faraday Cage).
Wouldn't this same issue arise from driving a ground rod at a detached garage that is being fed from main house/building?
@@mikewhitlock1849 Great question, no. Why not? Because if you follow the lightning surge current between the two electrodes, there is no electronic equipment in the path. Also the NEC requires an electrode at the service [250.24(A)] and at a remote building [250.32(A)] to accommodate both system grounding [250.4(A)(1) and equipment grounding [250.4(A)(2)].
I'll add that in industrial electronics, grounding is a type of black magic...
You are so correct!
So if the outdoor electrical equipment sets an Auxiliary Grounding Rod, a good additional design is also setting an SPD at the Pannel, to protect the EDS inside the building. SPD should based on the 10/350 test wave.
Surge protection in this example would not make a difference from the induced current from the lighting. SPD are always a good idea.
Please watch the entire video, not just the short. Click on the link embedded on the bottom of the short.
@@MikeHoltNEC Ye, thanks Mike:)
Not needed as per code is similar to the EIA/TIA standards that restrict pipe bends to 180 degrees and disallow conduit bodies for communication cables. We had to follow specs on equipment with electronics. Installed them per specs, did not violate code, got paid, went home.
But what about a bonded neurtral generator with gfci? Wouldn't that need a three pole transfer switch to switch both hot legs and your neutral therefore your generator would need its own electrode system correct?
Yep, per 250.30(A). Wow... you are one sharp cookie...
Mike what about lightning supresion systems and more then one grounds that are not connected.
My first asumption is never connect this to the main panel ground.
@@chauvinemmons Lightning protection systems are required to be bonded to the building grounding electrode system in accordance with 250.106.