fuse size question

[Jimg]

I am running a 2/0 welding cable from the front battery to the rear distribution block I was planning on using a 250 amp fuse

I am using a 4 way mini anl fuse block to go from the 2/0 cable
to 4 gauge wire coming out of the fuse block to the amplifiers

slot 1 I will have a US Acoustics 1500 watt amplifier what amp fuse would be used in the distribution block

Slot 2 a US acoustics 4x100 watt amplifier what amp fuse would be recommended?


slot 3 a small power pioneer amplifier to run tweeters

slot 4 Dayton DSP , power relay may also have some led lights

Click to read more...

 

[Dafaseles]

Those U.S Acoustics amps have their own fuses right? If they do, I'd just fuse to the rating if the 4 awg. Which if it's done good ofc stuff, if I'm not mistaken, it's 200-250 amps.... someone will correct me if I'm wrong.

 

[Jimg]

yes fuses included in the amplifier


I am using ofc wire on all runs

power
ground
speaker wires
all ofc

 

[Firewalker]

Need one 18" or so from the battery and then one on the distribution block for each amplifier of course. Mine is setup for 300 at the battery and then 200 amp for the 2k monoblock and then 100 for the small 100x4 4 channel. I use full size ANL though not that makes a difference one bit, just easier for me to acquire here locally is all vs the min-anl fuses.

 

[Popwarhomie 5,000+ posts]

The fuse is only for protecting the wire. Fuse for the amperage rating of the wire.

 

[ThxOne Premium Member]

My setup is similar. I run a Stinger 350a circuit breaker less than 8 inches off the battery. I am running 0awg OFC from the breaker to the distribution block. No other fuses except what comes in the amplifiers. 4awg OFC to the two amplifiers. US Acoustics Barbara Ann, all channels driven @ 4 ohm. Rockford Fosgate Prime 1200-1D. RF DSP. I have popped the breaker twice, both on very hot days and both times on BASS heavy music at full tilt for about 15min with the car idling. Normal battery, stock 125a alternator.

Basically if you are wanting to fuse... something totaling between 300 and 350a should do the trick. The Breaker near the battery allows you to cut power to EVERYTHING downstream so you can work on whatever you want.

 

[Firewalker]

Of course the fuse is for protecting the wire, common sense. And yeah fusing for the amperage of the wire is normal, but at the same time it doesn't hurt anything going over it either.

I have thought about putting in that breaker type like you have as well. I think my fuse holder is about 8-10 inches away from the battery iirc.

 

[ThxOne Premium Member]

Of course the fuse is for protecting the wire, common sense. And yeah fusing for the amperage of the wire is normal, but at the same time it doesn't hurt anything going over it either.

I have thought about putting in that breaker type like you have as well. I think my fuse holder is about 8-10 inches away from the battery iirc.

It is handy. I break the circuit every time I work on something. In the next ride, I will add my fused block. For the OP, hope this helps.

 

[audioholic 5,000+ posts]

When sizing fuses the length of the wire has to be considered along with the wire gauge. This is why fused distro blocks are usually worthless, and even slightly detrimental. If you size your fuse correctly for the longer run from the batt to the rear of the vehicle (and the distro block), that fuse size will still protect the smaller gauge wire you distro'd down to, assuming that rear run is a short length (usually). At that point, adding an additional fuse at the distro block, just because a person might think a smaller gauge wire always needs a smaller fuse, is only additional resistance in the circuit.

As for circuit breakers, keep in mind they are relying on physical resistance to set their fail point. Unlike fuses, if a circuit breaker is used in a harsh environment that causes corrosion, it will alter the trip point. I've seen circuit breakers that were corroded solid, completely eliminating their purpose as a safety feature. So under-hood installations should always be a fuse, and only use circuit breakers in controlled environments like a vehicle's trunk or passenger compartment.

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