I'm planning on installing 400W amp for sub bass, and a 140W amp for mids and highs. From the battery I'll run this wire to a distribution block in the trunk to feed both amps. I'm thinking a 4ga wire should handle the load from both amps. Also what fuse rating should be used for this wire. One fuse for the main power harness, and two seperate fuse for the amps.

 

If you only have 2 amps, that more than enough. As far as amp fuses under the hood, I have 2 amps, and each amp is wired as 2, so each amp is fused at the amp at 50amps. I have an 80amp circuit breaker under the hood that is fine.

 

Definetly 4 ga is enough and the fuses he mentioned are plenty big.
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