Fuse question

[nsxdemon]

Quick question regarding fuses:

So I'll be running 1400W RMS from two amps in parallel. So from a 12V source (the battery), I'll have an RMS current output of around 116 amps. So first question...do I use a 100-amp or a 150-amp fuse?


And second, (and more importantly) why should I bother even using a fuse in the first place. Our stock alternators are 90 amps, so if I exceed that, the entire electrical system will go to hell right? I'm assuming the electrical system goes Alternator -> Battery -> Electrical components, so if the car's running, the stereo's going and the alternator can't keep up, major problems will ensue!


Just wondering since I'll be getting the fuse holder, fuse, and distribution block asap and I don't wanna get the wrong specs!

 

[changedman]

use a car audio circuit breaker, and run an amperage thats equal to the highest output.

 

[Rider69]

the fuse or c/b is there to protect in case of a short in the wire. If there was not a fuse or c/b and the power wire shorted, it coudl short out your battery and really F up your electrical system or even cause a fire. I would use a 100A fuse or a 110A C/B. Fuses usually have a little more leeway as far as blowing when the A is exceeded. SO you could go lower than your actual Amp draw, C/B are not as lenient. And will open easier when there is excess than the rated amps of the C/B. Save $ on fuses but C/B are a little more expensive to start.

 

[sndsgood]

your protecting the wire, your are not protecting your amps. in an accident if the wire is pinched it can ground out and instantly melt and catch fire. so now you could possibly be stuck inside the car with your carpet on fire, not to mention that the shroud covering the wire is toxic to breathe and can cause lung damage. your protecting the wire. simple as that. as far as what fuse to use. use a fuse that is large enough to cover your amps draw but not to big to be useless to the wire. for instance. say you have 2 gauge wire that is around 15' long. it can problaby handle somewhere in the 150-200 amp range. now say your amps equal 75 amps draw. if this is the case, dont waste money on a 75 amp fuse. get a 150 amp fuse. remember your protecting the wire, not the amp. if you get a 75 amp fuse, who knows, a year down the line u may get a bigger amp and now your buying a bigger fuse. i tend to prefer fuses over circuit breakers, i just trust them more. and if your always careful when you install, you wont have to wory about fuses, in 15 years ive never blown a fuse.