High leg on phase other than B

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hambone1216

Member
Location
Rochester new york
I work in the Rochester NY area, and the local power company, is requesting that i place the high leg on the outside set of lugs (c phase)in the CT cabinet for metering purposes. Then code requires that i place the high leg on B phase in the panel.

My problem is that some of the panels that will be fed from my new service have the high leg on C phase. Do the sub panels all have to be changed to having the B phase as the high leg. Or does the main service only fall in the category of B phase only for high leg?
 
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fmtjfw

Senior Member
Location
Fairmont, WV, USA
Power company metering typically expects the high phase to be on C.
Typically the B and C phases are interchanged between the metering and the service disconnect to put the high leg on the B (center) of the service disconnect.
In some cases when the metering is embedded in the switchgear, the high phase remains on C.
 
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texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
hambone1216 said:
I work in the Rochester NY area, and the local power company, is requesting that i place the high leg on the outside set of lugs (c phase)in the CT cabinet for metering purposes. Then code requires that i place the high leg on B phase in the panel.

My problem is that some of the panels that will be fed from my new service have the high leg on C phase. Do the sub panels all have to be changed to having the B phase as the high leg. Or does the main service only fall in the category of B phase only for high leg?
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I gather you are building a new service in an existing facility. This is a problem in older installs as the NEC did not require the high leg to be "B" until around the mid seventies. Prior to that it was customary to put it on the "C" position as that was what the POCO's did (and still do).

I think I would talk to your inspector and see what you can work out. Maybe do all the new stuff on "C" to match the old for consistency and agree to have all panels well signed and maybe a sign on the main disco. indicating the premises has the high leg on "C".

I don't think it would be reasonable for the AHJ to make you change all existing panels to conform if you are not touching them.
 
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