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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7107
Experience:  Proven Professional 46 years Experience
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I have a 150amp, 480 volt, 3-phase main breaker in a fire

Customer Question

I have a 150amp, 480 volt, 3-phase main breaker in a fire pump disconnect. I'm having the utility company bring in a separate service to exterior meter socket. Local utility company will only bring 4- wire system to building so will have 277/480 volt meter ped. I figured they would stop the unneeded natural conductor in the ped but they are requesting that it stop at first main service disconnect in this case fire pump control panel. Over all I'm trying to size the non-needed neutral conductor as small as possible since there will never be any load on it. Everything is leading me to go off table 250.66 which 1/0 is required for 150amp feeder so #6cu or #4AL should be the minimum size conductor I can use.... Correct or ?
Thanks in advance for your help!
Lance
Submitted: 11 months ago.
Category: Electrical
Expert:  Mike G. replied 11 months ago.

Hi, I'm Mike G and I'll be assisting you. You are correct. Check Art250.102 C 1.