Outside feeder

[hhsting]

I have two outside conductor feeding building: one is a feeder feeding panel A 240/120V single phase and another is 208V three phase circuit feeding air compressor in building.

I know i would need to ground Panel A to grounding electrode system of building. Do I need to bond the 208V three phase circuit equipment ground bus to the building grounding electrode system too? I am confused

 

[augie47]

Yes. Both need to meet the requirements of 250-.32

 

[hhsting]

Yes. Both need to meet the requirements of 250-.32

Would not NEC 2017 Article 250.32(A) exception regarding a single branch circuit apply with equipment grounding conductor so not providing the grounding electrode apply to the 208V three phase circuit for air compressor?

 

[wwhitney]

Would not NEC 2017 Article 250.32(A) exception regarding a single branch circuit apply with equipment grounding conductor so not providing the grounding electrode apply to the 208V three phase circuit for air compressor?

The exception only covers the case of a single branch circuit supplying the structure, no other supplies. Since you have a single feeder plus a 3-phase branch circuit, the exception doesn't apply.

Cheers, Wayne