I'm working on the wiring of my RV.

I don't know how to pick the correct fuse size. If I've got, say, two LEDs (maybe 1 amp together) and a fan which said "no bigger than 4 amp fuse" on the wire, do I combine the total amps of all the electronics to pick fuse size? Or what?

I did an overkill on the wiring, it's all 12 gauge. So fusing according to wire size won't work, here.

I'll have pretty low draw on all the wires.

So how do I go from what the appliances I have on each circuit draw, to deciding what size fuse to put on the circuit?

Thanks!

 

I do not know what the formula is but you have to go bigger than the highest draw. you could start with a 5A and if it blows too often, switch to a 7.5A. I would guess a 10A would be too much.

 

Assuming everything is wired in parallel, the sum of the branch currents should equal the applied current, which is what you need to fuse for. The total current should be your voltage divided by your total circuit resistance.

 

So how does one figure circuit resistance ??

 

Resistance is voltage divided by current(amps).

 

Ok, thanks. I overdid it on the wire. I put in 12 gauge wire for circuits that probably don't have any more than 5 amps ever drawn on them, so the wire burning won't be a problem so long as I fuse for the appliances.