Ok, I'll admit THWN is not the best choice for under hood automotive. I still say it will be ok.

Some automotive primary wire is only rated for 80 or 90 C at 50v.

Most wire is run thru wire looms or wrapped in tape from the factory for additional protection. It is good to protect the wire in this way and secure it. Things can rub thru with vibration. One key is to keep the wires away from the more hot pieces like the exhaust which can run in the 400 F range or more if somethings wrong.

Everything except the battery cables is fused or has fusable link wires (except for a few slip ups from the factories). An electrical fire most likely is from a shorted batery cable or an unfused wire shorted. Too many people just hook on a wire to the battery. Also don't delete the fusable link (a short piece of smaller gauge wire by a power distribution point).

Some vehicles do run hotter under the hood like if it has a turbo. But for a typical POS it will last until the next thing breaks.

Auto wire distribotor spec's:
http://www.jaguarind.com/products/pvc/wire/gptprimary.html
http://www.condumex.com/ing/cableautomotriz/cable_primario_pvc_xlp.html
http://64.233.179.104/search?q=cache [Linked Image]jhFr4ke5EQJ:www.awcwire.com/pdf/ct-c1-sxl-sgt-gxl-txl-gpt.pdf+automotive+wire+temperature&hl=en

Tom

[This message has been edited by Active 1 (edited 04-20-2005).]