Is there anything in the NEC, or anywhere else, that requires the service neutral to be the same size as the phase conductors? I recently installed a 480V, 3 Phase, wye service to an industrial facility. The local power company would't give us power because the neutral was one size smaller than the phase conductors.
Service Neutral Size
- Thread starter JakeW1
- Start date
- Status
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
There is no such requirement. There are rules though governing minimum size. See 250.24(C) and 220.61. I'd be very surprised if the vast majority of services did not comply with 220.61 with just a 1 size smaller grounded conductor. In some cases it could be as small as allowed by Table 250.66 (as directed by 250.24(C)).
Last edited:
ceb58
Senior Member
- Location
- Raeford, NC
The power company doesn't have to play by the NEC. They have their own set of regulations. If this was one of them then they can refuse you service until it meets their specifications.
- Location
- Massachusetts
I agree 100%, but I will add that if they are refusing I would ask to see the written rule of theirs that you are violating.
- Location
- Illinois
- Occupation
- retired electrician
It the conductors in question are on the load side of the service point and the power company rules do not apply, however it may take action by the state utility commission to get them to understand that.
- Location
- Massachusetts
Regardless of which side of the service point I still think they can refuse to power up if they are following their written and approved standards.
For instance some utilities require RMC for a riser even if the NEC allows SE or PVC.
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