NM Cable

[sparks1]

Art 334.80 The Ampacity of Type NM cables shall be determined in accordance with Art 310.15

What table deals with the temperture rating and ampacity of NM cables as decribed in Art 334.80?

 

[ken987]

Re: NM Cable

310.16 60 degree

 

[sparks1]

Re: NM Cable

I thought you'd say that!
Why isn't NM cable listed in the 60 degree colume in table 310-16?

What type of insulation is on the NM conductors is it TW ?

[ April 15, 2005, 03:06 PM: Message edited by: sparks1 ]

 

[suemarkp]

Re: NM Cable

NM-B is strange because in the end you are limited to the 60C column at the most. But NM-B has 90C conductors and you can use the 90C column for ambient temp derating and deratings due to bundling of conductors.

All recent NM I've seen looks like THHN, whereas UF looks like TW.

 

[charlie]

Re: NM Cable

It probably is THHN without the nylon and markings. It is only required to be rated for 90?C.

 

[sparks1]

Re: NM Cable

It's odd stuff alright! In the smaller sizes NM looks TW insulation and in larger sizes, such as 6/3 the conductors looks like THHN .

[ April 15, 2005, 04:37 PM: Message edited by: sparks1 ]