Multiple amp fuse wiring question...

[jwild4x4]

Multiple amp fuse wiring question (fun w/ numbers)...

Ok, I have an Alpine HU which requires a 20A inline fuse, and I'm getting a RF 451s amp which requires a 40A fuse. I plan on running 4 guage wire from my battery to a fused distribution block. I want to have a fuse right at the positive battery terminal in addition to the two in the fused dist-block.

My question is what is the rating i should use for the fuse by the pos battery terminal. Do I:

1) add the two 20+40=60 amp fuse
2) take the inverse of their additve inverses (1/x=1/20+1/40) = 13.3 amps, or
3) use a 40 amp fuse as it is the highest rated fuse in the system.
4) Quit being so damn **** and throw an extra .357 bullet I found laying around in there (going for the darwin award here).

Thanks in advance.

 

[VairKing]

#1

 

[Alec]

Except make sure every other component in the line can handle 60A.

 

[silver stripe]

your inline power fuse should be no more then the max amount of your fuses added up.

all the fuse packs you see with the crazy fuses like the one i got, 150amps , is just a show piece, and in the back its gone through another fuse pack to the back that you cant see thats got a 60amp as i have 3 x 20 amp fuses

 

[jwild4x4]

Alec, would I need to make sure every component can handle 60? I thought that the components downstream of the fused distribution block would be protected by their respective 20A and 40A fuses.
PS: I miss Splat!

 

[Alec]

They will be, but the wiring between the battery and split will need to handle 60.

 

[expo5.0]

yes, put a 60 up front then fuse the others as needed downstream.

one thing though- just fyi (you may already know) but most amps already have built in fuses, so the fuse you are adding in are only protecting the power cable. Many of my good friends a few of them who even install professionally (me included here) do not usually fuse every wire in this type of a situation. What i've done in my own truck is to run a 200 amp cb up front... and thats it. of course if you blow something up don't blame me

 

[jwild4x4]

Thanks for the input.... Yeah i've had a power cable ground on me before, and would rather not re-live that experience. The amp im getting has an external fuse protection, but i didnt want the wire to burn up under my carpeting etc should it accidently ground somehow. Thanks for your help gentlemen.

 

[mhn3773]

when i grounded the power cable in my car it just killed my batt took a few days to went to start and nothing so i learned the hard way to fuse even if the amp has one built in =) o yah also unplug the neg terminal on the batt when working but thats another story lol