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#82083 - 10/16/02 11:34 AM High phase  
Steve T  Offline
Joined: Feb 2001
Posts: 306
Oak Park, IL, USA
I had a contractor inform me that the utility required the high phase to be the C phase. I told him it has to be the B phase.

Is it acceptable to install the high phase as C phase in the CT cabinet and then become the B phase in the MDP?

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#82084 - 10/16/02 01:11 PM Re: High phase  
resqcapt19  Offline
Joined: Nov 2000
Posts: 2,148
The high leg must be landed in the right side position in most metering equipment to make the meter work correctly. When you come out of the meter to the service disconnect, you must move it to the center position. Look at 408.3(E) and the exception.

[This message has been edited by resqcapt19 (edited 10-16-2002).]


#82085 - 10/16/02 04:35 PM Re: High phase  
tdhorne  Offline
Joined: Mar 2001
Posts: 345
Maryland, USA
For the sake of my continuing education would that mean that if the metering equipment is in a separate enclosure that the high leg would have to be terminated on the B phase of the service equipment but if it is in the same enclosure as the metering equipment it can follow the metering arrangement? Understand that the only delta power I have done has been derived systems rather than service equipment.

[This message has been edited by tdhorne (edited 10-16-2002).]

Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison

#82086 - 10/16/02 04:45 PM Re: High phase  
resqcapt19  Offline
Joined: Nov 2000
Posts: 2,148
You are correct. If the meter is in the same enclosure, you are permitted to keep the high leg in the C phase position. As soon as you get to a second enclosure the high leg must be in the B phase position. If you use a phase rotation meter, you will find that the high leg is always B phase. It is just something in the meter configuration that requires the high leg to be in the right hand or C phase position.


#82087 - 10/16/02 05:34 PM Re: High phase  
Bjarney  Offline
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
Some highleg whys and wherefores covered at

With modern solid-state meters, aside from old customs and habits, the righthand/highleg location does not matter any more so far as accurate meter registration is concerned.

#82088 - 10/21/02 12:24 PM Re: High phase  
Steve T  Offline
Joined: Feb 2001
Posts: 306
Oak Park, IL, USA
Thanks Don

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