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Sub panel grounding

e hilton

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Reading a discussion on another forum, the HO wants to add a subpanel next to his main panel, because the main is full. Separation is just a few inches. Question about grounding the new panel. Will a ground wire be required between the panels, or is the metal nipple sufficient?
 

Joe.B

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Dec 4, 2020
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Arcata Ca
Separate Bonding Jumper required. Also, "grounds" and "neutrals" will need to be isolated at the subpanel.
 

steveray

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250.28 would apply to a service or SDS. The sub panel would fall under part VI of 250. As long as the metal nipple meets the requirements of 250.118 no additional wire type EGC is required.
That is what I was thinking...and they would just have to not bond the neutrals to the enclosure as the enclosure is now the EGC path...
 

Joe.B

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I would have said 250.80/250.86, but I'll stand corrected by 250.118, good work.
 

ICE

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As much as I like the code there are some areas that beg for improvement.....using conduit for grounding is one of those areas. I seldom see an installation where the conduit is used for grounding. For one thing, the ground path is supposed to be a low impedance path....that translates into good old American made copper wire.
 
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jar546

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As much as I like the code there are some areas that beg for improvement.....using conduit for grounding is one of those areas. I seldom see an installation where the conduit is used for grounding. For one thing, the ground path is supposed to be a low impedance path....that translates into good old American made copper wire.
Commercial jobs we see it a lot. There is a lot of testing data showing that metal conduit is a better EGC than the required wire.
 

ICE

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Commercial jobs we see it a lot. There is a lot of testing data showing that metal conduit is a better EGC than the required wire.
True enough. I used to inspect more commercial than residential and even then not many jobs relied on conduit for EGC. Maybe it’s a left coast thing. For the last few years I have inspected mostly residential and it is work done by grossly inexperienced workers. The drawback for me is that a raceway EGC is only as good as the workmanship.

All it takes is one loose fitting and then what have you got. That and if I say EGC they wonder if that’s going to require a trip to the hospital.
 
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steveray

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True enough. I used to inspect more commercial than residential and even then not many jobs relied on conduit for EGC. Maybe it’s left coast thing. For the last few years I have inspected mostly residential and it is work done by grossly inexperienced workers. The drawback for me is that a raceway EGC is only as good as the workmanship.

All it takes is one loose fitting and then what have you got. That and if I say EGC they wonder if that’s going to require a trip to the hospital.

Was trying a remote video inspection on a 3000A school service/ electrical room and asked the electrician if the conductor was the EGC or GEC and he said "Hunh?"
 

Rick18071

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Nov 28, 2009
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That is why in CA we require fulltime inspectors for schools and hospitals.
What does that mean. The inspector is at the school or hospital 40 hours a week, they have to be a electrical inspector full time, or they can be a full time building, mechanical, plumbing, electrical inspector? Why couldn't they be part time?
 

chris kennedy

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Oct 24, 2009
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Miami Fla
Was trying a remote video inspection on a 3000A school service/ electrical room and asked the electrician if the conductor was the EGC or GEC and he said "Hunh?"
I recently had an inspection on a new service for industrial equipment. (No Romex involved)
The inspector looked at my GEC landed on the grounded conductor bus in the main disco and said that needs green tape. I told her its a GEC not an EGC and she started Googling???
I pulled out one of my code books and showed her 250.119 then flipped to 250.50 and asked her to show me the article for "Identification of Grounding Electrode Conductor", which there isn't one.
She kept Googling so I put green tape on it which I removed after she left.
West Palm Beach inspectors Jeff. Thought you were educating these people.
 
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