hey guys can you give me some advice on fusing matter? I bought a 0 guage amp kit so later I don't need to upgrade... but right now I'm going to install 2 amps and the total watts running is about 700w... a 250 ANL amp fuse came with the kit....for the inline fuse holder under the hood. I was wondering if 250 amp fuse is safe use to protect a system that only run about 700w??? Should I downgrade its to 150 amp fuse??? for better protection...? any advice on this will be appreciated, Thanks
First find out the total of the fuses for each amp. Then add them together. Then you know what size ANL fuse to buy. I personally add about 5-10 in the total. Example: Amp A has one 45 fuse Amp B has one 35 fuse now lets add 10 and we have a 90 amp ANL fuse hope this helps
you can use the above method, however you can keep the larger one up there, the fuse at the battery primarily safeguards the wire run throughout the car, thus the 250A will effectivly protect that wire.
the above is correct but remember this if you do have a short somewhere the fuse will not blow out and you will still have electrical current flowing through the wire which could start a fire.
I've always prefered to go lower than the sum of the amps fuses... The fuses are set to blow just shy of what the amp can handle, however in a typical setup you'll only see half the amp draw of what is fused for. for instance with the setup that poohchriscd mentioned, with a total fuse rating of 80, you'll typically see a 40-50 amp draw (unless you're pushing it into clipping in which case it could spike). In this instance i'd start with a 60 amp fuse. If you blow it try a 70, this will better protect your amp. I look at it this way, I'd rather replace a $1 fuse than a $400 amp. My current setup includes an amp with a fuse rating of 60 amps, It's split to one 30amp fuse per channel and there are no fuses installed in the amp so i run a 30 amp fuse inline with the power wire for each input (one input per channel on this perticular amp). However at the battery I have a 40 amp fuse which has not blown in the last year of use. The 40 amp fuse would blow long before the two 30 amp fuses would which provides a higher level of protection to my $700 amp. In my opinion it's worth the risk of blowing the fuse...
Well actually, if you have a short, that's nearly 0 ohms of resistance... ...which would technically cause an infinite amount of amperes to flow. Realistically, even with a short circuit, there would still be a tiny amount of resistance... and the battery isn't that fast to respond, and there's internal battery resistance to factor in... but you are still talking about a massive, massive amount of current that would flow from a short circuit. More importantly, in the scenario that you are talking about - enough current flowing to make a 0 gauge wire get hot enough to catch fire - you would be flowing well in excess of 250a - so that fuse is still appropriate.
