I'm running either 1 or 2 gauge wire from my battery into a distro block that will then downsize into 4 gauge and feed my stereo and mono amps. My question is should I fuse the 4 gauge before it goes into the amp. I want to fuse just to be safe but am unsure of how many amps my fuse should be. The stereo amp is going to be pushing 500 watts rms and the mono amp is going to be pushing 650 rms. Both amps have two 30 amp fuses. Should I put an inline 60 amp fuse before the amp? I was also planning on using an AGU type fuse. What do you guys recommend?

 

Try using a 80Amp inline very close to the battery, thats what I would do, a single inline fuse is more than enough, and besides most (not all) distribution blocks have fuses in them as well.

 

yeah, your distro block on your power wire should be fused

 

I'm not buying a fused distro block and I am going to fuse the power wire within the first 18 inches from the battery. I just wasn't sure what my two fuses after the distro block and before reaching the amps should be. I would think that since both amps have two 30a fuses that 50-60 makes sense.

 

Watts divided by volts equals amperage. Problem solved.

 

The purpose of fusing the wire is to protect the vehicle in the event of a short circuit and the fuse should be sized for the wire. You want the fuse to blow before the wire gets so hot that it causes a fire. If you were to fuse to the 1 or 2 ga from the battery, you would need to fuse again when you step down in wire size at the distro block. If you don't want to fuse again at that point you have to make sure that your primary fuse is small enough to provide adequate protection to the smaller wire. IIRC 120A is the recommended size for 4ga.

 

120a for 4 gauge huh?

its not so much about the size of your wire as it is the amperage that is flowing through the wire.

 

The fuse at the battery is very much about the size of the wire and its max amperage not the amplifiers demand. Look at it this way: The wire gets caught in a trunk hinge or wears on a sharp chassis point and shorts to ground. The amperage flowing at that point IS determined by the size of the wire. You want the fuse to blow before your truck catches on fire. The fuse at the battery end protects your vehicle. The fuse at the amp end protects the amp.

 

agreed....that was my point. I HATE when people just assume that a particular size wire needs a particular size fuse. There is a lot more that goes into it other then gauge.

And if your stupid enough to run a power wire through a trunk hinge or door jam, you deserve what you have coming to you.

 

Finally found the chart i was looking for.

http://www.hifisoundconnection.com/S...ker-Wire#chart

No way should you be putting a 120amp fuse on 4 gauge wire in a truck install where the run is usually 15+feet. Hence the reason I run a 60amp fuse.

 

im using a 40Amp on 5G wire in my s-cab with 300.1 kicker amp. Its only about 150 watts cause its only on 4ohm.

 

That chart is not a fusing chart. Its based on voltage drop.

If you read what I posted you wouldn't have a problem with it either way. The OP said that he was running 1 or 2 ga to a distro block and from there 4 ga to the amp. Not sure where you got the 15' of 4 ga from. Regardless, that chart is one of the most excessively conservative that I have ever seen.

 

120A is perfectly fine to keep the wire from catching the truck on fire. That's all you're looking for from that fuse. Wire length has no bearing on how much current it can actually flow safely. It might not do so efficiently, but it is safe. It has nothing to do with the current draw of the system an sizing the wire correctly for that.

 

I have never had need for more than a 60Amp fuse, ever.

Unless you are just running a monster system, I doubt a person would need more than a 80 Amp.

I used to run a 1800D with a cap on two 12"s constantly for HOURS and never had any problem on oct gauge wire.

never had a cut out, or a over heat. Or a fire.

I do personally prefer blade type fuses, they seem to be more common around here.

 

I'm not saying that you need to run a bigger fuse, I'm just saying that you don't have to run smaller than 120A. I usually use a 150A on my 1/0 runs because I have them laying round. I really don't base my fusing decision on what is common because I don't plan on them blowing except in extreme circumstances.