External Sensor and Communications for UL 508A Panels

[vinceawolfe]

Hello, I am new to the panel design world and have questions after talking with a UL engineer about several topics. He insisted that I could only use connectors with a NIWT2 or PVVA category control number for thermocouples and RS-485 ports, which we have not been using. I have several years of inspection logs for the company I am with and there is no mention of anything special in our Procedure. Is there a path to this through the low voltage limited energy circuits portions of 508A that allow me to use the standard components we have been using for years? None of which have a UL rating. Thank you for any guidance you can provide.

 

[petersonra]

The answer is somewhat convoluted. generally components entirely within a class 2 circuits are not required to be evaluated.

However field wiring terminals for class 2 circuits are.

Whether a connectors is a field wiring terminal or not I really don't know.

I don't see how PVVA would be applicable since it seems to only apply to power circuit conductors. I didn't find NIWT2 in the component list at all.