Grounded conductor

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nec4me

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Is a grounded conductor required to be installed with a feeder supplying power to a 3 phase panel that doesn't need the grounded conductor for any of the branch circuits? An electrician told me that you always install the "neutral" to a panel whether it is needed or not, and the reason was that it will carry fault current back to the source. Isn't that what the equipment grounding conductor is for?

[ October 05, 2004, 12:24 AM: Message edited by: nec4me ]
 
Re: Grounded conductor

We have some terms that need to be clarifed
Grounded Conductor
Equipment Grounding Conductor
Ground

An equipment grounding conductor is always required to provide the fault current return path to the source, per 250.4(5), three phase, two phase or two wire.
The grounded neutrtral conductor can never be used in a building per 250.142. A EGC is always required per 150.118 but it can be a wire or conduit.
 
Re: Grounded conductor

This doesn't apply to an ungrounded delta but otherwise yes. when the system supplying the service has a grounded circuit conductor it is required. 250.24(B)

fault current only want's to return to source not Earth. With out a grounded service conductor at the service you will only have the ground rod at the pole and service to fault a short and since the resistance is to high in Earth no OCPD's will open.
 
Re: Grounded conductor

Thanks for the quick replies. So if I understand you guys correctly if I had a 3 phase panel that was 100' from the service equipment that only fed 3 phase motors then you would not need a grounded conductor run to the panel 100' away?
 
Re: Grounded conductor

While it's not required when it's a 208/120 volt system I think it's a good idea to bring the grounded circuit conductor to it as somewhere down the road someone will try to use the EGC for a neutral. But this is only my opinion not of the NEC.
 
Re: Grounded conductor

A neutral conductor does not have to be supplied to a panel that does not require a neutral, such as some motor loads. An equipment grounding conductor must be installed with those feeders, whether that is in the form of a metallic raceway or a conductor.

250.32(A)(2) permits the grounded conductor for dual purposes, as a grounded conductor and an equipment grounding conductor, so you would not be specifically required to install an equipment grounding conductor in that instance.
 
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