For people who are wondering if their 4 or 8 gauge wire is long enough or good enough for their amps.

 

BTW, that's continuous power ratings. If you have an amp that peaks at 1000W (real Watts, not "printed on the box" Watts) and you're running a cable from your engine compartment to your trunk (let's call it 20'), you don't need 1/0 Ga. You only need that if your amp pulls 1000W RMS.