That's what I thought; thanks for the reference.
No
There's a table of insulation types with the wet and dry location ratings in the NEC in Chapter 3, Article 310 I think. Away from my computer so I don't have a more exact reference.
No without the -2 it's a 75° C conductor.
No, 75 wet, 90 dry.
If you made wire, would you want to make a second, inferior version?
Southwire makes THWN without the -2 in sizes smaller than #8.
That's what I thought; thanks.
Yes T 310.4
The inferior versions of the wire are previous generations of the same family of products, before the modern THWN-2 rating became available. THWN without the -2, is 75C wet, and THHN is 90C dry, and the inferior wire usually carried these two ratings together. The -2 suffix gives it a rating of 90C in the three most common environments (i.e. wet/damp/dry). THWN-2 automatically implies both THHN and THWN without the -2. You'll see all three designations on the same print legend, despite the fact that THWN-2 already implies the other two. Some datasheets have smaller sizes (e.g. #10 and smaller) carrying only the inferior rating (THHN/THWN only), while you don't get the full THWN-2 rating until you have larger sizes.
One note: If its outdoors but not in a wet location then the interior is not considered wet. The top side of a roof would obviously be, but the underside of a outdoor pavilion roof may be a damp location.
Since what is a wet location is undefined in the NEC it leaves the decision to the AHJ. I can see there being AHJs who don't split hairs and just say all outdoor raceway is in a wet location. That's what I assume, I don't see there being a win by sectioning up a raceway into outside wet and outside dry divisions. I take a wholistic approach. If I have a conduit on the roof and that transitions to running under an eve then the dry section under the eve will most likely be wet also, since water runs downhill.
