ECN Forum Forums General Topics of the Trade General Discussion Area Using THWN on automotive circuits

Since I retired I am back into my lifelong passion for working on my vehicles, I'm up to 5 now. I've been buying automotive primary wire at the parts store but we all know how expensive that is, and the rolls are small. So I have a lot of stranded THWN left over that I'll probably never use, today I used some of my #10 THWN for a fan circuit on the RV. Not much difference that I can see, the strand count looks a bit less on the THWN but the insulation feels tougher. They both seem to have about the same flexibility and unruliness I sleeve it all in corrugated split loom anyway.
Anyone else do this or see a problem?

My boat is wired with THHN/THWN in FS boxes, conduit bodies and RNC. 35 years in salt water hasn't fazed it. I even have some yellow wirenuts in there (EEEK!!). They do have a squirt of silicone grease in there. The only warning I would have is "flexible" doesn't mean the same thing in a car or boat. If this wire is just going to lay there, well restrained it will outlast that auto parts store wire. If it's going to move every time you hit a bump, buy the good stuff.

Ditto with Greg.....

Thanks, no movement or bending/flexing expected. It's secured to the frame rail over to the auxiliary oil cooler fans. This is on my RV chassis, inside the RV itself they used Romex.

I usually put that black plastic loom over wires I am installing to give them some protection similar to the OEM. Napa and most auto parts places have it or you can order it online a little cheaper.

I use that stuff as well, on all my wires and hoses for protection as well as aesthetics. It is a lot cheaper online. Autozone sells 10 feet of 3/8" made by Dorman for $9.99. I just bought 100 feet of the same 3/8" Dorman product on Amazon for $14.20

I have used it also in similar cases though I highly recommend THWN-2 for the temperature rating, and once I am in the engine compartment I change completely. There I worry about oil resistant and a much better heat resistance based on where the wire may sit.

The black plastic loom protects the THWN from road oils but not in the engine compartment unless I am far from any possibility of spray and heat can be much different.

Shane

I have to fess up that I used THHN/THWN on my boat, after running out of 'Marine" conductors doing a rewire job. Secured with loom and ty-wraps and had no issues.

Back in my younger days, working on my cars, "whatever was around" worked fine.