Supply Connection conductors

[arnettda]

I have a piece of equipment that states for Supply connection use 90 degree C copper wire. Does this mean just the wires that connect to the piece of equipment? Could I run 60 dg C wire to a disconnect on the wall and then 90 deg C wire to the piece of equipment. That as how I read it since it says supply connection and not supply conductors?

 

[James L]

I have a piece of equipment that states for Supply connection use 90 degree C copper wire. Does this mean just the wires that connect to the piece of equipment? Could I run 60 dg C wire to a disconnect on the wall and then 90 deg C wire to the piece of equipment. That as how I read it since it says supply connection and not supply conductors?

That's how I see it. I have the same situation with a pool control panel. It says used 90 degree copper. I thought about running aluminum to a disconnect, then copper from the disconnect to the control panel

 

[petersonra]

I have seen this kind of stuff too and I have no idea why they would ask for it. What I suspect is it is a misreading of the UL listing requirements for the piece of equipment. I've seen this kind of thing on UL 508A control panels. Usually it ends up saying something like use 60° c copper conductors only. I'm not sure where that comes from, other than there are some field terminals that maybe do require 60-degree copper conductors but I think it's something somebody decided was a good idea 20 or 30 years ago and people are afraid to change the marking.

In the case of UL 508A, what I think they probably meant was to use the ampacity numbers from the 60°C column, although I'm not entirely sure why they would want to do that.

 

[infinity]

Same thing would apply to a light fixture that requires 90°C conductors. The entire circuit would not require a 90°C conductor only the potion connected to the equipment.