Fuse Questions

[nick6533]

for some reason, fuses seem to confuse me. I have a few questions:

1. If an amplifier requires a 250 amp fuse, does that mean that its amperage draw is 250 amps? and thus you would need a 250 amp alternator? (obviously it would be more to accomodate the vehicle draw, but I'm speaking hypothetically).

2. If you run two runs of 1/0awg wire to an amplifier, would you fuse both runs with a fuse that is half of the amplifier's fuse rating? i.e. an amplifier that requires a 300 amp fuse, would each run of power wire be fused with a 150 amp fuse?

[MrSkippyJ]

1. No and yes. It's a give and take thing. It's a combination of battery and alt providing power. You can have enough alt power to fully supply the amp's needs, but it's usually easier and cheaper to use batteries to back up the alt. that's the short answer.

2. Fuse to the wires rating typically, not the amps. So in your example, use 2 300amp fuses.

[nick6533]

Thanks for the help!

So there is nothing wrong with having too large of a fuse? This doesn't put the amplifier at any risk?

[Wicks]

Power cable runs should be fused to the current rating of the wire.

Amps should be fused to their power rating.

[nick6533]

Well isn't the power cable's fuse also the amp's fuse? I don't see where you're coming from

[Tim Osburn]

the amps usually have a fuse on the amp. when you are putting the fuse at the beginning of the wire close to the battery that is protecting the wire for any shorts in the wire or over drawing the wire(pulling to much current). so thats why you get a fuse that is rated for what the wire is rated for. i you run wire that is rated for 125 amps thats the size fuse you should go with at the start of the wire run or smaller. if you go with a bigger fuse then the wire isnt protected.

[Sonic]

Normally, the power wire current capacity is greater than the fuse rating of the amp. In the case of one amp, you can use the size of fuse recommended for the amp on the wire, this will protect the wire and the amp. and if you have 2 runs of power wire then run both runs to the one fuse rated for the amp.

If you have more than one amp then use a fused distribution block, where each output is fused for the specific amp's capacity and the main power wire or wires into the distribution block is fused to the capacity of the wire.

The above applies to amps that require external fusing.

[nick6533]

the amps usually have a fuse on the amp. when you are putting the fuse at the beginning of the wire close to the battery that is protecting the wire for any shorts in the wire or over drawing the wire(pulling to much current). so thats why you get a fuse that is rated for what the wire is rated for. i you run wire that is rated for 125 amps thats the size fuse you should go with at the start of the wire run or smaller. if you go with a bigger fuse then the wire isnt protected.

The amps I've been considering are the AQ2200 and Crescendo BC2000, neither of which have fuses on the amp. So what do I do in this case?

[nick6533]

Normally, the power wire current capacity is greater than the fuse rating of the amp. In the case of one amp, you can use the size of fuse recommended for the amp on the wire, this will protect the wire and the amp. and if you have 2 runs of power wire then run both runs to the one fuse rated for the amp.

If you have more than one amp then use a fused distribution block, where each output is fused for the specific amp's capacity and the main power wire or wires into the distribution block if fused to the capacity of the wire.

Thanks for the good advice. So if I'm running an amp that doesn't have a fuse in it, I should fuse to the amps fuse rating? Because in this case it protects the amp and the wire? (being that the fuse rating is at or lower than the wire's rating)

[larrys95civic]

are you running another battery in the back or going straight to your amps?