Just wondering what is the difference and what is better for my different applications.
Thanks.
W indicates sutiable for use in wet locations.
most thhn wire is dual rated as thwn.
check to be sure the wire you purchase is so.
THHN is a code for heat-resistant thermoplastic wire which is allowed for use in dry to damp locations and rated for a maximum temperature of 90єC (194єF).
THWN is a code for heat- and moisture-resistant thermoplastic wire which is allowed for use in both dry and wet locations but has a lower maximum temperature rating of 75єC (167єF).
As nap said, wire can be dual rated (THHN/THWN). Be careful not to misread the code as there are similar ones for different type wires (such as THHW) while others have suffixes (such as -2) which change the wire’s rating.
the temperature usually also indicated on the wire?
I don't recall seeing a temp rating on the wire I generally use although it could be. Never really paid that much attention to it. I'll have to take a look.
The temp rating I have is within the NEC.
So if the wire is dual rated thhn thwn is it usually 75C or 90C and/or is it
If the wire is duel rated it can be used at 75 c if used in a wet location or 90 if used in a dry location.
THHN/THWN-2 can be used at the 90 deg rating in a wet or dry location.
Keep in mind that the 90 deg columb is rarely if ever the final amp rating for a given wire size. In DIY work, it will likely never be the final amp rating of the wire. The purpose of the 90 deg columb is for a starting point when doing bundling, ambient temp, etc calculations.
If running conduit and individual conductors, most of the time the limit will be the 75 deg columb, as the lugs on the equipment will only have a 75 deg rating.
If running NM or NMB cable (romex) the limit will be the 60 deg columb, regardless of the wire type.
Apologies in advance for slightly hijacking this thread but is dual rated acceptable for over head (in air) use to supply power to another structure? (Four # 10 suppling a 30 amp sub panel for example.)
duel rated just means rated for more than one thing. If the wire is duel rated for thhn/thwn, then no not for overhead wiring. If the wire is duel rated for overhead and something else then yes.
Ray,
Overhead wiring must carry a UV/sunlight exposure rating which THHN/THWN does not have.
Overhead wires must also be supported by a load-bearing messenger wire which is only included in the triplex/quadplex cable assemblies that are sold for overhead services.
ibpooks, thanks for figuring out my somewhat unclear post. (I left out THHN/THWN). So I'm assuming the way I learned with individual conductors fastened to individual insulators is no longer permitted.
I assume if you were running to a garage with other metallic pathways you'd need a four wire cable assembly. I doubt fourplex even exist when you get down as small as #10, correct? Dang, didn't want to go the burial route.
I assume if you were running to a garage with other metallic pathways
you'd need a four wire cable assembly.
Yes. It's highly recommended anyway.
I doubt fourplex even exist when you get down as small as #10, correct?
The smallest I've seen is #2 aluminum which is rated for 100A as a dwelling feeder. In any case, I hardly ever recommend feeding an outbuilding with anything less than #2 aluminum.
If you really want a smaller feeder, I know the power company uses #4 aluminum, so you might be able to get your hands on that somewhere.
Thanks all. Guess I'll have to dig.
I think anxiter wire and cable or windy city both sell retail.
Let your fingers do the walking. if a wire is made, those two companies can get you some.
Quadplex is fairly common, but as stated not in smaller sizes.
Tags: difference, thwn, thhn, wire, dual rated, duel rated, wire cable, wire dual, wire dual rated, wire duel, wire duel rated
