[rf17830]

I'm an AV Installer and I have installed many runs of high quality speaker cable in hot attics. I've never seen any degradation of the cable jacket. I wired my van using Genesis brand speaker wire that I had in my inventory. I would recommend using a 2-conductor speaker cable with a "CL2" rating printed on the jacket. Good brands are Genesis, Belden, and even Monoprice.

In no case should you use the zip cord that is sometimes, used by home owners, for speakers. That is the two conductor cable that has a clear jacket. The "real" speaker cable has two individually insulated stranded conductors inside an outer jacket. It will always have the "CL2" rating printed on the jacket. I always buy it by the 500 ft box.

 

[rf17830]

Speaker wire. Decent quality but not expensive. #18 for small puck lights, #12 or #10 for outlets, etc.

18 gauge
14 gauge
12 gauge
10 gauge

Don't use the wire that you linked on Amazon. This wire has an copper clad aluminum core. It isn't good for a van build.

 

[rf17830]

CL2 and CL3 are fire ratings. It means that the cable won't carry a flame into a wall cavity. It is an indication of a high quality cable. The manufacture spent money on UL testing and certification of the product.

The Honeywell Genesis, Belden and Monoprice speaker cables are widely used for AV installations. They are used in hot attics without any issue.

 

[rf17830]

Here is a chart to calculate wire temperature rise.

Temperature Rise by Current | ISRayfast

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