Wire size

[suemarkp]

But when calculating from hot ambients, you can reduce ampacity from the 90C column with NM-B cable. So #14 NM still has 19A of ampacity in a 130F ambient area.

It may not be obvious, but when increasing the amacity because the area is cold, you can increase from the 60C ampacity. When reducing it because of high temperatures, you can reduce from the 90C ampacity.

 

[James L]

But when calculating from hot ambients, you can reduce ampacity from the 90C column with NM-B cable. So #14 NM still has 19A of ampacity in a 130F ambient area.

It may not be obvious, but when increasing the amacity because the area is cold, you can increase from the 60C ampacity. When reducing it because of high temperatures, you can reduce from the 90C ampacity.

I'm gonna look that over a bit.

 

[infinity]

But when calculating from hot ambients, you can reduce ampacity from the 90C column with NM-B cable. So #14 NM still has 19A of ampacity in a 130F ambient area.

It may not be obvious, but when increasing the amacity because the area is cold, you can increase from the 60C ampacity. When reducing it because of high temperatures, you can reduce from the 90C ampacity.

That's why the NM in an attic is really a non-issue. I've never seen a cable that burnt up due to the ambient temperature of the attic. Besides quite often the cable is under the insulation so it is not in 130° air anyway.