I'm wiring 240V/50amp Cal Spa tub and am concerned about the wire I picked up at the hardware store.
I bought Red, Green and White 6 awg THHN wire but the store was out of black. They sold me black wire labeled 6 AWG, USE-2 or RHW-2 (600V) to use instead. Its all copper, and all #6, only the insulation is different. Its for a fairly short run of about 25'. Should I be concerned??
Thanks,
Tony

No problem for this application. THHN and RHW-2 are both rated for 600V.
The only difference is the insulation as you noiticed.

Thanks!