Comparable code section to UL508A

[aNerdyEngineer]

Hi,
I'm looking to see if anyone knows of a comparable code section in NEC to that of UL508A section 29.1.2 and it's exception:

29.1.2 All internal wiring shall have insulation rated for the maximum voltage involved.
Exception: The voltage rating of conductors connected to a dc circuit, such as a dc bus or dc motor
circuits supplied from power conversion equipment, shall be the peak equivalence of the rms voltage
(rated voltage of the conductor multiplied by the square root of 2) marked on the conductor.

 

[tom baker]

See 300.3 C

 

[petersonra]

See 300.3 C

Has something been added to a recent code because I don't remember anything like this in 2017.

 

[tom baker]

300.3 c 1 is about insulation values. It is the closest section to what the OP asked

 

[petersonra]

300.3 c 1 is about insulation values. It is the closest section to what the OP asked

But it does not say that you can use a much higher value for insulation just because it's a DC bus on a drive

 

[jaggedben]

Right, the NEC does not have anything like the exception in the UL citation, afaik. Otherwise 300.3(C) is a similar idea.

 

[jaggedben]

But it does not say that you can use a much higher value for insulation just because it's a DC bus on a drive

Do you think the UL exception says that? I find the language somewhat inscrutable, but I don't think it says that.

 

[petersonra]

Do you think the UL exception says that? I find the language somewhat inscrutable, but I don't think it says that.

It does say that pretty explicitly.