A few more I have been asked several times recently:
Q: If my amp already has a fuse do I still need a fuse on the power wire near the battery?
A: Yes!!! The fuse on the amp
protects the amp. The fuse at the battery
protects the wire. General guidelines state you should put the fuse within a foot or so of the battery and in any case it
must go before the wire passes through ANY metal (make sure to use a rubber/plastic grommet at that point).
Q: How do I know what size wire and fuse I need?
A:The power wire size is determined by the capacity needed for any equipment connected to it and length of the wire. The fuse size is determined by the capacity of the wire over that length. It is OK to use a fuse smaller than required for the capacity of the wire but it is NEVER OK to use a fuse larger than the capacity of the wire. On the other side, it is OK to use a wire size larger than needed but it is NOT OK to use a wire smaller than required for the determined capacity (as soon as I have a few more minutes I'll post a link to a wire size calculator or if someone else has one please post it)
Q: How long can my ground wire be?
A: The length/size of the ground wire is determined by the
capacity of said wire. As long as the ground wire has at least the same capacity as the positive wire you can run it all the way back to the battery if you want (that's how we do it in boats and other situations where you cannot get a good ground elsewhere
). BTW, this of course is assuming you already have a properly sized positive wire to start with
Almost forgot, I actually prefer a circuit breaker instead of fuses
