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[sooperxtool 10+ year member]

Searched and searched and searched some more but nothing seems clear or absolute about what inline fuse rating to use and how to determine it. All I think I have figured out is that if I run multiple amps, I should use one fuse in the main power wire, and then one per each power wire that is distributed from the main. Is this correct at least? Who can shed some needed light on this? I'm sure its simple but I can't find jack on the subject.

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[Kangaroux 5,000+ posts]

Every wire gauge has a different amperage rating. 4 gauge is usually fused for 150A, 8g for around 80A, 1/0g can range from 250A to 300-350A whether it is CCA (copper clad aluminum) or OFC (oxygen free copper).

If you are running multiple amps you can buy a distribution block. The distro has a main power input and then branched outputs. Each output is fused. Ideally, you put a fuse for your main power wire right next to the battery. The distro takes care of the rest of the fusing for the smaller wires.

Digital Distribution System

That distro has switchable 1/0g or 4g inputs for the main, and switchable 4g or 8g for either output. When you purchase it you can choose a fuse size. It also has a built in voltage meter.

 

[winkychevelle 10+ year member]

depending on the wire the fuse rating differs gennerally

1/0 300amp max

2gauge 200amp max

4gauge 150 amp max

8 gauge 80 amp max

10guage is 30 amp max

for the main run up to 20 foot then the rating starts to drop

for your distrobution block it is not neccesary to fuse the wire unless the amps connected dont have fuses on them. then the fuse should be within 18 inches of the amp and rated at what the amp calls for.

 

[sooperxtool 10+ year member]

Ok, so in my case, I'll be using Knu Fleks 1/0 from battery, and I should fuse that with a 300a, and then I can run it to a non-fused distro splitting to a 4g and an 8g (and another 8g down the road) and I would not need to fuse each of those assuming each amp has built in fuses?

Thanks for the help

 

[Kangaroux 5,000+ posts]

Ok, so in my case, I'll be using Knu Fleks 1/0 from battery, and I should fuse that with a 300a, and then I can run it to a non-fused distro splitting to a 4g and an 8g (and another 8g down the road) and I would not need to fuse each of those assuming each amp has built in fuses?
Thanks for the help

I would still fuse it to be safe. But yeah that's pretty much how it would go. Snag a 1/0 fuse holder from knu and load it with a 300A, and get a 2-way distro and fuse it with a 150A and a 80A

 

[Bettr n' Revrse 5,000+ posts]

In short you fuse for the wires max rating not for what your amps pull... Since most amps are fused internally they can take care of themselves if something goes wrong...

 

[KyleBechtold 5,000+ posts]

In short you fuse for the wires max rating not for what your amps pull... Since most amps are fused internally they can take care of themselves if something goes wrong...

Yes and no.. If you run a 1/0 line that can handle 300a but you are running an amp that only pulls 180-190max there is no need to put a 300a for the vehicles sake.. you should go ahead and put a 200 in that way the amp can still be somewhat protected as a surge big enough to pop a 300a fuse would probably annihilate the amp.. most amps that are large enough to need 1/0 are not internally fused

 

[bubbagumper6 5,000+ posts]

for your distrobution block it is not neccesary to fuse the wire unless the amps connected dont have fuses on them. then the fuse should be within 18 inches of the amp and rated at what the amp calls for.

Anytime you change wire sizes (i.e. in a distribution block) you need fuses.

 

[KyleBechtold 5,000+ posts]

Anytime you change wire sizes (i.e. in a distribution block) you need fuses.

this! because if they ground out after the distro that wire is smaller so it will melt before that fuse on the main line pops and could cause a fire

 

[sooperxtool 10+ year member]

Thanks for the good info guys. Just want to be sure I do it right.