3-phase delta

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travis

Member
Re: 3-phase delta

B Phase although I cant give you a code article because my code book is not with me at this time but im sure it is b or center phase.
 
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george t. everett

Senior Member
Location
New York
Re: 3-phase delta

The Power Company in my area requires The high leg tobe connected to C phase in metering equipment. Would it be a code violation to connect the high leg to C phase in the meter and to B phase in the panel?
 
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websparky

Senior Member
Location
Cleveland, Ohio
Re: 3-phase delta

NEC 2002 408.3 Support and Arrangement of Busbars and Conductors.(E) Phase Arrangement. The phase arrangement on 3-phase buses shall be A, B, C from front to back, top to bottom, or left to right, as viewed from the front of the switchboard or panelboard. The B phase shall be that phase having the higher voltage to ground on 3-phase, 4-wire, delta-connected systems. Other busbar arrangements shall be permitted for additions to existing installations and shall be marked.
Click to expand...
 
roger

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Re: 3-phase delta

George, YES it would, look at Ryans post.

Edit: And Websparky's

Roger

[ August 06, 2003, 07:44 PM: Message edited by: roger ]
 
S

sjaniga

Member
Re: 3-phase delta

As stated 408.3, does specify to place the high leg in a switchboard or panelboard on the B phase, unfortunately this does not apply to meter cans and it is very common to place the high leg on C phase, this would be a poco requirement, and as long as both ends have an orange marking this would not be a violation.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Re: 3-phase delta

Many of the older meters had to have the high leg in the right hand position to make the meter work correctly. Even when the utility put the high leg in the right hand position it was still "B" phase as far as the actual rotation. Where the utility requires the high leg in the right hand position in the metering equipment the electrician must place it in the center position in the panels.
Don
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: 3-phase delta

Originally posted by george t. everett:
If it is a violation, then I have to connect the high leg to C phase, because that's where I have to connect in the meter.
Click to expand...
Look at 408.3(E) for the phase arrangement and then take note of the exception.

The following is from the NEC Handbook:
"The high leg is common on a 240/120-volt, 3-phase, 4-wire delta system. It is typically designated as ?B phase.? Section 110.15 requires the high-leg marking to be the color orange or other similar effective means of identification. Electricians should always test each phase to ground with suitable equipment in order to know exactly where this high leg is located in the system.

The exception to 408.3(E) permits the phase leg having the higher voltage to ground to be located at the right-hand position (C phase), making it unnecessary to transpose the panelboard or switchboard busbar arrangement ahead of and beyond a metering compartment. The exception recognizes the fact that metering compartments have been standardized with the high leg at the right position (C phase) rather than in the center on B phase.

See also 110.15, 215.8, and 230.56 for further information on identifying conductors with the higher voltage to ground. Other busbar arrangements for making additions to existing installations are permitted by 408.3(E)."

The bolding above is mine. :) We require all metering where a high leg is present to be marked and located in the R/H position (bottom if the CT's are mounted vertically.)
 
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