Parallel conductors, al/cu

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petersonra

Senior Member
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Northern illinois
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engineer
Can al and copper conductors be used. For example. 1 hot copper and the second hot aluminum?


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Take a close look at 310.10(H), especially 310.10(H)(2).

It is not clear to me what you are actually asking so I do not have an answer for you.

If you are asking if you can make one phase paralleled Al and the other paralleled Cu, the answer is different than if you want to use an Al and Cu conductor in parallel on the same phase.
 

electricalist

Senior Member
Location
dallas tx
My buddy is studying for his masters and said he couldnt find where is says u cant have a phase paralleled 1 al and 1 al

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roger

Moderator
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Location
Fl
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Retired Electrician
My buddy is studying for his masters and said he couldnt find where is says u cant have a phase paralleled 1 al and 1 al

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If both conductors of A phase are AL why would there be a problem?

Roger
 

Carultch

Senior Member
Location
Massachusetts
My buddy is studying for his masters and said he couldnt find where is says u cant have a phase paralleled 1 al and 1 al

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You can use a completely different configuration for all three phases, as long as your configuration OF EACH PHASE is internally identical.

Why you would want to do that, I do not know. It would be difficult in a practical sense of building a phase diverse feeder, and difficult to convince the inspector that it meets the NEC. Plus your voltage drop calculations are going to be confusing as hell.
 

roger

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Can 1 be al and 1 cu

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Petersonra's post has the code section, each phase has to be of the same characteristics but the different phases do not, for example, Phase A can be made up of AL XHHW and B could be CU THWN-2

Roger
 

electricalist

Senior Member
Location
dallas tx
Thanks actiondave. I misunderstood the question my buddy and i were debating. You answer what he was asking.

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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Thanks for all the replies.
Is there a instance where a being co and b being al would be used?

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It is not prohibited so it is strictly a design decision.

For instance, you might have some copper wire left over from an old job that you want to use up so you run one phase in copper and the rest in AL.

Or maybe you run one phase in copper because it lets you use a smaller conduit.
 
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