Thanks! I used the 10/3 SJOOW from Home Depot that they sell by the foot. I'm not sure what the temp rating is I'll have to look at it when I get a chance. I don't know what the temp rating actually applies to either. If its just the outer insulation it doesn't really matter since I removed it to fit the wire down the tube.
I've only had time to use it for one brew so far, but I'm not really worried about the temp rating on the wire whatever it is. I can't imagine it being soft enough to actually melt at boiling temperatures and I haven't seen any signs of anything getting too hot. If you have easy access to a higher temp rated wiring for a reasonable price it sure couldn't hurt, but I wouldn't go out of my way for it.
I still need to find someone who can put a 90 degree bend in mine since I ordered it without the bend. The only reason being that it won't fit in my HLT on the top tier of my stand because its too close to the ceiling.