so if I'm producing roughly 60 amps nominal, an 80 amp fuse would be good?

 

Ideally, you should try to stay within 10% of the current draw...
Reallistically, there are low chances that something bad will happen with your 80A fuse. Not imposible, just not likely. In any case, a new fuse costs way less than a new car

 

again, start at the amp.... The fuse that it has in it is the MAX that the amp is supposed to be able to draw and that is the number you want to aim for.If your amp has a 60 amp fuse, then run 4 awg with a 60 amp fuse. The fuse on the power wire at thebattery is not to protect the amp, it is to protect the power wire. If you have a power wire with too large of a fuse in it the wire canliterally weld itself to the chassis if the power wire shorts, before the fuse blows...60 amps is a hellofalot ofcurrent... It only takes .01A to kill you......

 

i still say 200

 

The only problem I have is using a fuse the same size as the one one the amp. Is that an amp that pulls 59 amps can blow a fuse that is 60 amps.

I don't have the curves on me, but there are actually fuse response time curves for protecting from various problems such as overcurrent or a dead short.

Really each one has thier own parameters and should be fused accordingly. If you have a dead short, you will blow any fuse that's current rating isless then thatof the resistive effects of thewire on thepower delivered to the amp.

Now now ttocs, .01 amps CAN kill you, but it doesn't all the time.

 

I can agree with that and go with a fuse that is slightly larger. But again if you have the same 60A fuse in the amp, will it not blow that fuse now first?

 

It should.

But that assumes that both fuses are within 100% accuracy andthe wiring is sized correctly.

Really, it would be best to a 61 amp and a 100 amp fuse in series on a wire feeding a 60 amp amp.

You would assume the 61 amp would blow first, but a great voltage difference could still jump the gap if the circumstances are right. The 100 amp fuse should also blow depending on the time needed to melt, but should provide an additional layer of protection.

 

that confuses me. putting two fuses in series?

 

Ok.... That's a bit extreme PReal. Considering that to bridge a 1/4 inch gap you need a pressure of about 3500 Volts, I'd love to know what your "right conditions" within a car would be...

By the way, you don't fuse to protect the wire. You fuse to protect the circuit itself, or the power supply. The main fuse should accomodate the current draw of the entire system, protecting it from damage that may occur. If you wanted to protect the wire, then you would use a fuse that's rated at the maximum current that the wire would carry, but you don't use a 100A main fuse if you have a 250W Amp connected to AWG4 cable.

The amp's internal fuse is only the first tier of protection. Should it fail, then the next fuse up the line should protect the circuit it's attached to, not the wire itself. (And no, that doesn't mean that the fuse could be of higher capacity than the wire...). If the amp starts to fail, then a main circuit blowing in a timely manner can make repairing the amp less expensive than if it continued to bake...

 

spyder you could not be more wrong, the fuse at the battery is to protect the wire and only the wire. Why would the fuse, almost 20 ft from the amp be for the amp? The fuse at the battery is in case the power wire shorts.