Equipment Grounding Conductor

[jdhklh2]

GIVEN:
Metal ?U? shaped pole barn.
Service panel 200 amp 120/240v 1p3w.
Service panel with grounded conductor, equipment grounding conductors, and grounding electrode system all bonded to the enclosure.
Service panel has a 60/2p feeder breaker serving a feeder panel.
From service panel in metal conduit to weatherhead, 3 insulated conductors.
Overhead triplex conductor connected between two masts. Attatched with open air splices
Weatherhead and metal conduit with 3 insulated conductors to feeder panel.
Feeder panel 120/240v 1p3w.
Feeder panel with grounded conductor insulated from enclosure and isolated from all other conductors. Equipment grounding conductors and ground rod bonded to the enclosure.

QUESTION: 250.2
Is an equipment grounding conductor required to return the ground fault to the service panel ( electrical supply source ) or earth?

 

[hurk27]

Re: Equipment Grounding Conductor

The Earth will never be able to open any breaker that is at 120 volts potential. and that is all you will have to Earth on a 240/120 volt system. think about it at the required 25 ohm's it will only produce 4.8 amps of current. you must have a low impedance path that is capable of faulting the Maxim current likely to be imposed on it. This means you must have a solidly connected conductor capable of faulting a short circuit all the way back to the source (transformer neutral)

Earth should never be used as that path.

 

[hurk27]

Re: Equipment Grounding Conductor

You are allowed to bond the grounding to the neutral at a out building if there is no other metal paths between the out building and the building where the feed originates. 250.32(B)(2)

Metal path's:
water pipe, Gas pipe, phone wire, cable coax, Etc...

[ October 04, 2004, 07:36 PM: Message edited by: hurk27 ]