Re: Boat Wiring
Is there a problem with having 20amp fuses on the lights? also one more question...should I have an inline fuse on the red wire near the battery? The fuse box has a fuse for each electronic already, just wanted to make sure. I am going to go buy some smaller amp fuses for my fish finder. I think 20amps is too much. I'm thinking 5amp should be good for the fish finder.
I would not run 20 amp fuses for anything... except maybe a lighter socket.
Your lights will probably be only 2 amps max for standard nav and anchor lights (1004 bulb is about .94 amp) and sonar (fish finders) are often less than one amp draw. My old Eagle has run on a 3A fuse for 14+ years without ever blowing. Think it is rated at like 3 watts.
I run 12 gauge or 16 ga wire for everything (less voltage loss)- usually 12ga when more than one load will be on one wire. Then I still use the smallest fuse that works for the load. While theoretically 12 ga stranded wire may be able to sustain a higher load (according to the insulation imprinting, which could even say something like 20A at 600V), I would try to avoid loading wire in a boat to the max of its rating. I try to limit one run of 12ga wire to 10 amps combined load at 12V which
is overkill, but safe. The small amount of wiring in a boat makes the additional cost and weight really a small sacrifice to pay.
It is likely there are many in the forum here who know more than I, but overkill has worked quite well for me in boats. I also would add a circuit breaker for your each main wire from the battery.
Hope this helps.