1000V rated wiring in UL1741 Listed assemblies

[MWh_Pro]

Hello Everyone,

I have an issue where I will need to run short lengths (<6 ft) of 1000V insulated wiring for ampacities up to 400A. Typically for UL 1741 listed equipment we were able to use THHN or AWM, since only the 600V insulation was required. Now, I am looking to find a wire that could be used in a manner much like AWM, but UL 1741 does not mention anything about acceptable wiring methods. I need 1000V rated insulation, minimum. I have looked to UL 508A for guidance, but its ampacity table only goes up to 75 degrees C. Frequently terminals of PV equipment are rated to 90 C, and I would like to use the full ampacity afforded by the conductors-- at these ampacities wire is incredibly expensive! I've identified several types of wiring that might fit my purpose, but I was just wondering if any of the users here had encountered an issue like this before. Could you help me out?

The main candidates I have are:
RHW-2 (not sure how the ratings would apply for internal appliance use) - UL category code (CCN) "ZKST"
PV Wire - UL CCN "ZKLA"
Power & Control Cable - as used in NEC 336, UL CCN "QPOR"
Wind Turbine Tray Cable - UL CCN "ZGZN"
Telco, Battery Cable - UL CCN "ZGZN"

A couple questions:
1. Which wire type do you think would be the cheapest?
2. Are there any you think would be inappropriate for this application?
3. Which ampacity tables should I apply for the internal wiring? UL 1741 does not contain this information. NEC 2011 310.15(B)(16) = 3 conductors in a raceway, @ 30 deg C, then derate to 50 C per the expected ambient temp?
4. It seems that the scope of UL1741 intentionally omitted constraints to wire sizing and type, and perhaps if I merely size my wire such that the terminal temperature ratings and wire insulation ratings are not exceeded, then I am in the clear. Would you agree?

I'm thrilled to have found this forum--I hope to contribute, myself--and I greatly appreciate all of your help!
Dave

 

[MWh_Pro]

In reviewing my post, I see now there was too much filler. Here's the lite version:

I imagine that more common wire is cheaper. Type RHH or RHW-2 should do nicely, since they both can be used up to 2000V, RHH 90 C (dry) and RHW-2 90 C (wet/dry).

Given the properties of the above types--and the apparent lack of information regarding appropriate wire types in UL 1741--I should be able to use the minimum size/gauge that does not violate the wiring insulation ratings for temperature and voltage. This will be demonstrated in thermal testing. Do you agree or disagree? Thanks!

 

[ron]

In reviewing my post, I see now there was too much filler. Here's the lite version:

I imagine that more common wire is cheaper. Type RHH or RHW-2 should do nicely, since they both can be used up to 2000V, RHH 90 C (dry) and RHW-2 90 C (wet/dry).

Given the properties of the above types--and the apparent lack of information regarding appropriate wire types in UL 1741--I should be able to use the minimum size/gauge that does not violate the wiring insulation ratings for temperature and voltage. This will be demonstrated in thermal testing. Do you agree or disagree? Thanks!

Sounds reasonable and the RHH or RHW is a valid insulation type in the NEC.

 

[MWh_Pro]

Thanks for your reply, Ron!
Dave