What's the difference between RHW and RHW-2 insulation? 1

[plastcc]

Just poking around on US supplier websites it seems to me that the H indicates 75C and the HH indicates 90C. I also found where H indicates 75 C and the "2" indicates 90C. Then I ran into XHHW-2 and now I'm really confused. Anyone know?

 

[davidbeach]

-2 is 90 wet. HH is 90 dry.

 

[plastcc]

That's interesting. Does the same thing go for USE and USE-2? I always thought that USE was made for wet locations anyway.

 

[davidbeach]

For instance XHHW or THHN is 75 wet, 90 dry while XHHW-2 and THHN-2 are 90 wet or dry. So, (no code book at hand) USE is likely 75 wet and USE is likely 90 wet.