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ungrounded 2400 volt feeders

Posted By: Yoopersup

ungrounded 2400 volt feeders - 08/30/17 01:17 PM

2400 volt ungrounded customer owned feeder from OCP .
Run underground in PVC

, Equipment ground required ?? Shield as ground ???

2017 NEC Part X.
I'd prefer EGC. But I think Shield allowed in some cases.
Code section with answer Please.

If EGC required sized by 250.122.

Posted By: ghost307

Re: ungrounded 2400 volt feeders - 08/30/17 04:16 PM

You would need to run an actual ground conductor.
The shield won't do the job.
Yes; size it per 250.122.

Although technically the NEC doesn't mandate that you ground the 2400V system; I have always run a ground conductor...even if later someone tells me to not connect it.
Posted By: gfretwell

Re: ungrounded 2400 volt feeders - 08/31/17 04:58 PM

250.4(B) talks about grounding equipment on ungrounded systems. Although it does not specifically reference 250.122 it is implied as a good guideline with these words

250.4(2) Bonding of Electrical Equipment. Non–current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected together and to the supply system grounded equipment in a manner that creates a low-impedance path for ground-fault current that is capable of carrying the maximum fault current likely to be imposed on it.
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