NM Wire Designation Suitable For 220 V Residential Use ?

[Robert11]

Hello:

I understand that Copper No. 10 AWG is the correct wire size for a
circuit in a residence with a 30 amp circuit breaker.

If the wire used has the typical NM designation, is the insulation rated and
suitable for
220 V, as well as the conventional 110 V ?

Thanks,
B.

 

[John Ray]

Hello:

I understand that Copper No. 10 AWG is the correct wire size for a
circuit in a residence with a 30 amp circuit breaker.

If the wire used has the typical NM designation, is the insulation rated
and suitable for
220 V, as well as the conventional 110 V ?

Thanks,
B.

As others have pointed out, NM is fine voltage wise, but depending on your
application, its temperature rating may not be sufficient (ie. central heat)
in which case SE would be a better choice.

John

 

[John Ray]

NM-B is rated to 90C. But is heavily restricted to the 60C
applications, when rating for amperage.

So unless the OP is using the cable in nonresidential, extreme
environments, he should be ok. But always referr to the NEC for
specifics.

True, but the question refered to using 10AWG NM in a 30A situation.
Depending on what the actual usage is and, more specifically, what the
ambient temp is, he might have to derate the NM. In a case like this he'd be
better off with SE. In reality the NM would work fine, but for NEC
compliance we need more specific information.

John