Whats the difference in THHN/THWN besides the W for wet locations. Are these one in the same wire? I see it advertised as such. sometimes with and with out the THWN part. Just really curious about this

M

Washington1

Hope this helps:


THW-2: Thermoplastic Insulation (usually PVC), Heat Resistant (90°C rating), suitable for Wet locations.


THWN-2: Same as THW except Nylon jacket over reduced insulation thickness. Also rated THHN.




THHN: Thermoplastic Insulation (usually PVC), High Heat Resistant (90°C rating), dry locations only, Nylon jacket. Also rated THWN.

Key: Suitable for wet locations THWN
Key: Not suitable for wet locations THHN

People think they can run Thhn in coduit in wet locations, but they can't. Unless it has a dual THHN/THWN rating

stanfortyman

As a quick note, yes, todays they are one in the same. You will be hard pressed to find single rated THHN or THWN. Pretty much all THHN is dual rated with THWN.

mr500

I was thinking they were the same. BUT I'm gonna make cure it reads that on the sheathing I hate to do this twice. BUT Im sure its all the same with the new stuff out today.

Thanks Been a great help Off to spend that 1.78ft and dive into this stufff!!

Mike