Line to Neutral

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rmonroe

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Discovered a lighting panel in our plant which is using a three-wire system. Instead of a neutral wire they are using the building ground for the neutral. We do have a 277/480 Wye system in our plant.

I will run a new service to this panel to eliminate any safety issues. My question is where in the N.E.C.does it state that you cannot use the ground for your neutral?
 
Re: Line to Neutral

Section 250.142 (2002 NEC) prohibits the use of the grounded conductor (neutral) to be used for grounding equipment on the load-side of the service disconnecting means. (see exceptions)
 
Re: Line to Neutral

Section 250.6 requires the circuit equipment grounding conductors to be free of objectionable currents. The EGC is a safety circuit that used for carrying fault current back to the source and to actuate the overcurrent device(s). The use of the EGC as a normal current-carrying conductor causes circulating currents thru out the building structure, metal piping, ducts etc. There can be a potential difference between grounded conductive material which can be hazardous to personnel as well as a fire hazard.
 
Re: Line to Neutral

Great information...The contractor that is quoting this job could not find that article in the N.E.C.. Great web site!

Thank you
 
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