60 degree or 75 dgree?

[westelectric]

mc and bx cables. Which column do you use to size ampacity? I know romex is 60deg

 

[jwjrw]

The way I read Article 330.112 it's 90 deg insulation. But you use 75* to size OCP

 

[Jim W in Tampa]

You use 90 degree for derating and 75 for breaker size

 

[Ponchik]

http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet66

If the equipment is marked for use at higher temperatures, the conductor ampacity shall be limited to the following per NEC 110.14(C).
60?C - When terminated to equipment for circuits rated 100 amperes or less or marked for size 14 through 1 AWG conductors.
75?C - When terminated to equipment for circuits rated over 100 amperes or marked for conductors larger than size 1 AWG.
90?C - For ampacity derating purposes.

 

[augie47]

Basically what Edward stated... except there is a bit more to it.
110.14 would be your guide.
In practical applications you can normally use the 75? rating for termination, but 110.14 provides the "rule".
Don't overlook 310.15(B)(2) Exception 5 if the MCs are bundled.

 

[jwjrw]

Basically what Edward stated... except there is a bit more to it.
110.14 would be your guide.
In practical applications you can normally use the 75? rating for termination, but 110.14 provides the "rule".
Don't overlook 310.15(B)(2) Exception 5 if the MCs are bundled.

Augie what does " type ac or mc WITHOUT AN OVERALL OUTER JACKET" in 310.15 (b)(2) excp 5 mean?

 

[augie47]

There is such an animal as "jacketed MC".
I believe it is a type required in Art 547

 

[Ponchik]

http://www.southwire.com/products/AlumaflexTypeMCPVCJacketedALConductors.htm

 

[jwjrw]

There is such an animal as "jacketed MC".
I believe it is a type required in Art 547

Thanks! That makes sense.

 

[infinity]

Type AC cable in insulation must be used at it's 60? C ampacity, switch to MC and you can go to 75? C.