power wire fuse

The amp dont have a built in fuse..  and it calls for a 300 amp.. im just doing everythign by the book..

A ~3kW amp? Funny that they don't supply it..... I think you may need 000 gauge cable though.... else 2 lots of 2G. (And don't forget your GNDs!!)

got 0 gauge power adn ground.. made by monster

So does 0G handle 300A? HERE says 245A. 300A will generate 50% more heat than 245A.

In a 12V system 1/0 AWG will handle 300 amps. The site listed above says their ratings are conservative. Short Distance, not bundled and not in conduit. You are running a single wire with 90C or 105C jacketed copper. The load is not 100% duty factor and in less than 20 feet in most cases.

Thanks ACG. Amazing as it sounds, I never use such tables (except for mandated stuff - but that's usually AC and rarely if ever 12V-24V DC etc) - I go by resistance etc. Though I might sanity-check with certain handy tables.... But isn't 20' too long for heat conduction?   2' ok, but 20'? (That's more of a general inquiry - 10W per foot at 300A isn't too bad for 0G... - I'd guess warm, but far from hot.)