Amp Power Wire Blowing Fuses

[1991S13]

This is going on in my friend's Saturn. I'm not sure of specifics, but he has a Sony Xplod amp going to two 10" MTX subs...

The fuse on the 4ga. cable going from the battery to the amp keeps blowing. He called me to ask what was going on, and didn't really get into details, just said that the original fuse blew, so he put a new one in and that blew after a day, then the third one blew after working fine for like a week.

I am stumped, but I'm pretty sure this is a common problem. All help is appreciated, as always. Thanks, Kenny.

[PoorManQ45]

Put a meter on it. Check the voltage, resistance, and current draw with key off, at idle, and while driving. You will immediately notice any abnormalities if something is really wrong.

Either one of the wires is touching ground, or the fuse is too small

[Florida240sx]

Probably the fuse is too small.One my amp i kept a 30amp fuse in the power cord.When I put in a bass test cd and cranked he rup it would blow everytime. Amp is just drawing it's max power which is frying the fuse. what size is it do you know?I think my wire is 4ga and i got 150ap fuse. I had 30amp fuse on my 8ga.What size is the amp?

[PoorManQ45]

Florida: a 30 amp fuse is only ~360 watts at 12 volts.

150a = 1800w

[1991S13]

He had a 45 amp fuse in it and when that blew he replaced it with the same. After that blew he got like a 100 watt and that blew as soon as he put it in. I am not sure how many watts the amp is...all I know is it is a 4 Channel Xplod...I'll check later today at lunch.

Thanks.

[Rex]

A few basics ...

A power wire should have 2 fuses. First one should be at the battery to protect the car from burning to the ground if the power cable "grounds" between the battery and the amp (front to back, unless you've relocated the battery). This one should be 20 amp, 40 amp, 60 amp or larger, depending thickness of the wire. The second one should be at or in the amp, refer to manufacturers spec/reco.

Which one is blowing?

[1991S13]

Sorry for leaving that out...

It's the one that is in the engine bay.

[Rex]

Sorry for leaving that out...

It's the one that is in the engine bay.

The it should be bigger than the one "at" the amp, and thus it's preventing the car from burning to the ground (at least that's its purpose).

Assuming nothing wierd was done, more than likely the wire has rubbed against some piece of metal in the car and is allowing the wire to "ground". You need to find that soon.

[PoorManQ45]

Yey. Trace the length of the wire. Check to make sure that the insulation is in tact the whole distance. Then check the connections AT the amp. It's possibly that a single strand of wire is connecting the positive to the negative. It may not be obvious at first glance, but it's still enough to "blow" a fuse.

[Florida240sx]

I had the 8ga with 30amp amp was 300watts but true wattage was probably 330ish then I had a crossover module they said add's about 20-30 more watts.My new amp is 1500watts with my 150amp fuse