Thread: Which side of the distribution block should the inline fuse be?

I would put a big one one the main line close to the battery. And then a fuse for each "accessory" on the power distributor, close to the distributor. That way if 1 thing is bad, the individual fuse blows, and if something catastrophically bad happens, then the big one blows. Always good to have a contingency plan too, so 2 fuses essentially to each device is good, in my opinion.

Not to mention the smaller cables comming out of the distro block have a lower current rating. Whilst you might have a 250amp fuse near the battery which is fine for the main cable, 4 guage would melt with less than 250 amps I'd say, and you can see where that would lead to.

250A fuse will stand even starter

anyway one big fuse on main cable max. 30cm ( 1 feet) from battery and if you will notable lower cross-section of wires running from distribution block it is definitely good idea put smaller fuses on each wire right behind the block.

So what size fuses do you think I need for these?

computer
120 watt 4 channel amp
250 watt mono amp

there is simple formula : wattage peak + 10%

if your numbers is peak so let say:
-main source 90 - 100A fuse


if your wires from distr. block is short enough , apms and PSU has its own fuse, so you don't need any other fuses. But I think that your 8awg wire from battery to block is insufficient ...you need 4awg.

and here is recommended maximum fuse for vary wires
00 awg 400 amps
0 awg 325 amps
1 awg 250 amps
2 awg 200 amps
4 awg 125 amps
6 awg 80 amps
8 awg 50 amps
10 awg 30 amps
12 awg 20 amps
14 awg 15 amps
16 awg 7.5 amps



and here http://www.bcae1.com/wire.htm you can find a lot of information you need

Okay, so here's my plan of attack then.

4 gauge wiring from battery to distribution block in trunk.
125 amp fuse in this wire near battery.
8 gauge wiring from 250 watt mono amp to distribution block with 50 amp fuse.
8 gauge wiring from 120 watt 4 channel amp to distribution block with 50 amp fuse.
Computer power wire to......????

how long will be wire from block to amp?

for carputer you need wire rated for at least 10A ( I am not familiar with awg sizes 'cause I'm from europe but I think 14awg will be enough )

The amps and computer will be in the trunk and I guess I can put the distribution block anywhere it needs to be. I was thinking about the trunk to cut down on the length of wire from the amps to block.

so once again

if your wires from distr. block is short enough (about 2feet) , apms and PSU has its own fuse, so you don't need any other fuses put to wire.