Wire and fuse question

[someone16 10+ year member]

My friend is going to be running a 750 watt rms class d amp and then a 300 watt rms and the shop recommended 8 awg wire but i think he should go with 4 awg. Would 8 awg be enough? Also what size fuse should the main power wir to the distro block be fused with? I was thinking a 125 amp fuse would do nicely.

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[jb2xx 10+ year member]

For what your friend is going to be running, I would recomend 4guage. Don't even consider 8guage. If I were him, I would even maybe consider 2guage from battery to terminal block. From terminal block to 300w amp I would do the 4guage. For the 750W amp, I would go 4 guage as well.

The fuses are to protect the wires since the amps already have fuse protection. It is recomended that the primary fuse be as close as possible to the battery within or less than 12 inches. 100A fuse at the battery I suppose would be ok. At the terminal block, I would do 40A for the 300W amp & 60A for the 750W amp.

If anybody has other suggestions, please provide your input. If fuses begin to blow, it's a sign of a grounding problem. Not so long ago I had a grounding problem on my fused distro block.

 

[johnecon2001 5,000+ posts]

For what your friend is going to be running, I would recomend 4guage. Don't even consider 8guage. If I were him, I would even maybe consider 2guage from battery to terminal block. From terminal block to 300w amp I would do the 4guage. For the 750W amp, I would go 4 guage as well.

2awg would probably be best, but the 300watt amp doesn't need a run of 4 awg off of the distro. 8awg for that amp would be fine, but do use 4 awg for the other amplifier.

The fuses are to protect the wires since the amps already have fuse protection. It is recomended that the primary fuse be as close as possible to the battery within or less than 12 inches. 100A fuse at the battery I suppose would be ok. At the terminal block, I would do 40A for the 300W amp & 60A for the 750W amp.

100-200A on 2 awg, 80-120A on 4 awg. I would do 60A for the 300 however and 80-100 for the 750. You want to get as close as possible to the wires main capacity to leave your self enough headroom to draw the power needed.

If anybody has other suggestions, please provide your input. If fuses begin to blow, it's a sign of a grounding problem. Not so long ago I had a grounding problem on my fused distro block.

if fuses begin to blow it MIGHT be a grounding problem.. it could also mean you have too small of a fuse in place and your overdrawing it thus it goes "pop". You can fix this by upping the ampers size of the fuse.

 

[forbidden 10+ year member]

The fuse on the main power line is not to protect the wires, it is to protect the vehicle first and foremost. Protect the vehicle, you are obviousely protecting the wire. Lots of people assume that it is solely to protect the wire, this is far from the truth.

 

[n2audio 5,000+ posts]

The fuse on the main power line is not to protect the wires, it is to protect the vehicle first and foremost. Protect the vehicle, you are obviousely protecting the wire. Lots of people assume that it is solely to protect the wire, this is far from the truth.

You're chasing your tail.