conductor sizes

[kingelectric]

Do all conductor sizes for a 3-phase 480v feeder in a conduit have to be the same size? for example I seen a 20amp 480v feeder with 2-#12s and a #10 to each phase or do they have to all be #12s or upsize to # 10s using the same size conductors for each phase?

 

[ActionDave]

Except for rules that cover parallel conductors there is no requirement that all the conductors be the same size.

 

[ptonsparky]

Except for rules that cover parallel conductors there is no requirement that all the conductors be the same size.

Now, what size EG...Nah, never mind, it is in conduit, metallic, hopefully.

 

[Smart $]

As long as the smallest conductor is compliant, no restriction. Regarding parallel, all conductors do not have to be the same size either... but those comprising one phase must be the same size.

 

[ActionDave]

Now, what size EG...Nah, never mind, it is in conduit, metallic, hopefully.

Thought about that. Even if a green was needed the rules just tell us what size it must be, not that it has to be the same size as the other conductors.

As long as the smallest conductor is compliant, no restriction. Regarding parallel, all conductors do not have to be the same size either... but those comprising one phase must be the same size.

The part in bold was the reason I included parallel conductors in my reply.

 

[Smart $]

...The part in bold was the reason I included parallel conductors in my reply.

I was aware of that... but you did not elaborate to the same degree as I.

 

[ActionDave]

I was aware of that... but you did not elaborate to the same degree as I.

And a fine job of elaborating it was.:thumbsup:

 

[ptonsparky]

Thought about that. Even if a green was needed the rules just tell us what size it must be, not that it has to be the same size as the other conductors.

The part in bold was the reason I included parallel conductors in my reply.

If 12s were all we needed and we increased one of those to 10, do we have to increase the EG to 10?:angel:

 

[jumper]

If 12s were all we needed and we increased one of those to 10, do we have to increase the EG to 10?:angel:

Depends..... Is da 'spector lookin'?

 

[ActionDave]

If 12s were all we needed and we increased one of those to 10, do we have to increase the EG to 10?:angel:

I could use 10AWG for the hots and 8AWG for the green and white.

 

[Smart $]

If 12s were all we needed and we increased one of those to 10, do we have to increase the EG to 10?:angel:

I could use 10AWG for the hots and 8AWG for the green and white.

Yes statement... and also yes to answer his question. The EGC size would be based on the largest ungrounded conductor size to the circuit minimum with sufficient ampacity