What is the meaning of "-2" in RHW-2, THW-2, etc?

[Electricallearner]

Hi All,
I remember this question from the exam. The question asked what does the "-2" signify in these cables. Is it 90C, Wet/Dry or both? I just want to make sure... Sorry if this is asked many times before...

Thank you!

 

[Dennis Alwon]

If there is a -2 then the wire is rated 90C wet or dry. I believe that is correct

 

[LarryFine]

Correct; the wet rating = the dry rating.

 

[Dennis Alwon]

Hi All,
I remember this question from the exam. The question asked what does the "-2" signify in these cables. Is it 90C, Wet/Dry or both? I just want to make sure... Sorry if this is asked many times before...

Thank you!

If the -2 is missing then you will see that dry is 90C and wet is often 75C

Here is an example

 

[kwired]

Common is THHN/THWN/THW-2 marked conductor.

without the -2 it is only rated 90C as a THHN conductor and 75C as a THWN conductor. THHN is not rated for wet locations so you must use the THWN rating for wet locations.

With the -2 rating you have a conductor that is 90C rated for both wet and dry.