I have an outdoor transformer that feeds a commercial building. The contractor believes we don't need an equipment grounding conductor but can use the neutral (grounded conductor) only. The transformer will be grounded outside and the service inside the building will be grounded. I can't find anywhere in the NEC that allows this. I think that a Neutral and Equipment ground is required, please advise.
Serivce grounding via neutral
- Thread starter guywilson
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Re: Serivce grounding via neutral
The contractor is correct.
The transformer outside will have the neutral bonded to the case and ground, the service inside will have the neutral bonded to the enclosure and ground.
A grounding conductor between these two bonded items will be nothing more than a undersized parallel neutral, do not run it.
[ February 26, 2004, 06:02 PM: Message edited by: iwire ]
The contractor is correct.
The transformer outside will have the neutral bonded to the case and ground, the service inside will have the neutral bonded to the enclosure and ground.
A grounding conductor between these two bonded items will be nothing more than a undersized parallel neutral, do not run it.
[ February 26, 2004, 06:02 PM: Message edited by: iwire ]
highkvoltage
Senior Member
Re: Serivce grounding via neutral
iwire. Nicely stated. Have you ever ran into an inspector that will argue this?
I have. He claimed after the utility substation we were on the costumer side and that the grounding conductor had to be ran since we were subject to the NEC. We were feeding the X-mer with a delta feed and secondary was wye. The project engineer somehow changed his mind.
iwire. Nicely stated. Have you ever ran into an inspector that will argue this?
I have. He claimed after the utility substation we were on the costumer side and that the grounding conductor had to be ran since we were subject to the NEC. We were feeding the X-mer with a delta feed and secondary was wye. The project engineer somehow changed his mind.Re: Serivce grounding via neutral
This has been a hot topic. I agree with both the above. The method used by utility companies is designed and approved by engineers.
It makes no sense to install a smaller conductor for fault current when there is already a larger one present, namely the neutral.
This same situation is indicated on schematics of generator connections.
I will blast the generator connections later on.
I have connected generators from the Sahara Desert in Libya, to the South Pole,in Antarctica. I sure hope I did it right.
This has been a hot topic. I agree with both the above. The method used by utility companies is designed and approved by engineers.
It makes no sense to install a smaller conductor for fault current when there is already a larger one present, namely the neutral.
This same situation is indicated on schematics of generator connections.
I will blast the generator connections later on.
I have connected generators from the Sahara Desert in Libya, to the South Pole,in Antarctica. I sure hope I did it right.
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