if i put a fuse holder on my 4AWG power wire how many Amp Fuse will i need, if my amp is a MTX 2300 with 90A fuses altogether.(3 30s)

 

you'll want a 90amp fuse then if I'm reading that right.

 

Since the fuse at the battery is to protect the car in case of a short on the power wire, I usually recommend about 20% over the total draw of the amps, so a 100 or 150 amp breaker should be fine. I believe IASCA rules state this should be no further than 18" from the battery post, the closer the better.

 

where can i get a 90A+ fuse holder?? and how much can i expect to pay for it?

 

Unfortunately, it's pretty hard to find 90 amp AGU(cylindrical) fuses. Your best bet is to pick up a wafer fuse and fuseholder. Generally speaking, they're a bit pricier than AGU fuses/fuseholders, but that's the cost of high current draw. I'd suggest a 125amp fuse.

As for where to get them, most car audio shops stock this kind of thing, but there are a bunch of online places as well. Crutchfield and Sounddomain have a selection, and there's always a bunch of options on ebay.

 

would having a 60A fuse on the power wire still offer some protection in case of a short circuit?

 

I guess you could say that it would protect it too much. If your MTX is trying to draw 90amps from your battery, then it's going to blow every 60amp fuse you try to use. That's the idea behind fuses: they will not allow any current to pass that is higher than it's rating. Essentially, your amp will be telling the battery "Give me 90amps" but your fuse -- which is like an amperage watchdog -- will not allow it and instead will blow, breaking the circuit.

You have to allow the fuse at the battery to be at the very least the same amperage that your amplifier will be drawing. And like coalyard said, it's not a bad idea to overshoot by a bit. You just don't want a fire following your power wire to the passenger compartment.

 

would not having a fuse on the power wire be a bad thing?

 

nah, not until something shorts out and you have an electrical fire.. it'll work without one.. up to you if its worth it tho..

 

Yes its bad.

You should always have a fuse on the power wire, at least 18 inches to 24 inches from the battery.

Dont even mind what that other guy said.

 

If you're really worried about price, check out the ebay listings for "orion wafer fuse". Probably not the best stuff out there (I'm not sure about the Orion Wired wires and accessories), but it's only something like $4.99 for the fuseholder and $2.99 for the wafer fuse. Better than even thinking about going without a fuse.

Anyway, you've already invested in a high current amp, you may as well drop the extra coin to protect it and the rest of your car.

 

Like this one:

Orion Wired ANL Wafer Fuseholder

 

Use a breaker. It will also allow you to easily remove power from the whole system and reapply it without unbolting anything. The appropriate size is determined by your wire size (its the wiring you are protecting), and should be a size larger or at least equal to the total of your fuses, since your wire size should be conservatively chosen.

 

Heres some reminants of the old 3 Amp system. I guess I'm kind of a poser now.

 

Where can i buy one of those 125A stinger fuse holders?