how to determine inline fuse rating

[mat3833 10+ year member]

ok, so im going to be doing the Big 3 as well as pos and neg runs of 0ga to the trunk of my new car. i have 2 questions:

1. do i need to fuse the alt to battery wire for the big three and if so what size fuse?

2. how do i determine what size fuse to use for my power wire?

im goign to be running 0ga to a dristo into the 2 amps, then the 2 amps will run grounds to another distro which will run 0ga to the battery. i kno i fuse the pos wire, but im not sure what size to fuse it with. i will be running a kicker ZX-750 and a Autokek MM 1400.4(new model, 50 amps of fuse i think)

Matt

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[sacsking916 5,000+ posts]

ok, so im going to be doing the Big 3 as well as pos and neg runs of 0ga to the trunk of my new car. i have 2 questions:
1. do i need to fuse the alt to battery wire for the big three and if so what size fuse?

yes. the fuse rating is what the wire is capable of handling

2. how do i determine what size fuse to use for my power wire?

again, you are fusing for the wire. so whatever amperage the wire is capable of running at that is the amperage fuse i would get.

im goign to be running 0ga to a dristo into the 2 amps, then the 2 amps will run grounds to another distro which will run 0ga to the battery. i kno i fuse the pos wire, but im not sure what size to fuse it with. i will be running a kicker ZX-750 and a Autokek MM 1400.4(new model, 50 amps of fuse i think)

Matt

answers in red

 

[mat3833 10+ year member]

i thought you fused the amps power wire to what the amp would be drawing+10%. hmm, oh well. so 0ga is rated at 200 amps right?

Matt

 

[sacsking916 5,000+ posts]

i thought you fused the amps power wire to what the amp would be drawing+10%. hmm, oh well. so 0ga is rated at 200 amps right?
Matt

nope you fuse for the amperage that the wire will safely allow. so OFC 1/0 is 300a and CCA is 250

 

[NASTY08IMPALA 5,000+ posts]

If its ofc 1/0 its 300a if its cca its 250a yes u fuse for wiring capacity not amp

 

[NASTY08IMPALA 5,000+ posts]

nope you fuse for the amperage that the wire will safely allow. so OFC 1/0 is 300a and CCA is 250

^^^this..beat me to it

 

[mat3833 10+ year member]

hmm, ok. so looks like i need 2 inline fuse holders that accept 0ga.

Matt

 

[sacsking916 5,000+ posts]

hmm, ok. so looks like i need 2 inline fuse holders that accept 0ga.
Matt

yup. 1 from alt to battery. 1 from battery to rear. and if you have a rear battery 1 right in front of the rear battery. then 1 to the amp(s)

 

[itsblown 10+ year member]

For the power wire going to the amplifiers ive always looked at the total fuse rating on both amps, added them together and added another 10. Haven't blown a fuse ever

 

[mat3833 10+ year member]

wait, so i have to fuse BEFORE the distro block AND after the block before each amp?

Matt

 

[itsblown 10+ year member]

wait, so i have to fuse BEFORE the distro block AND after the block before each amp?
Matt

you dont have to run fuses at all, but it would be way more safe to have one upfront at the battery, think of how long of a run it is from the front battery to the back at the distro block. If anything happened in that run before the distro block like the wire was cut it would short to ground and there would be no fuse to blow and stop it and your car could burn to the ground... all hypothetical but, its possible

 

[mat3833 10+ year member]

well i was planning on fusing ~ a foot before the power distro. and not fusing before each amp, 0ga fuse holders get expensive and i already need 1 waterproof one plus another for the power wire.

Matt

 

[sacsking916 5,000+ posts]

well i was planning on fusing ~ a foot before the power distro. and not fusing before each amp, 0ga fuse holders get expensive and i already need 1 waterproof one plus another for the power wire.
Matt

youd be safer to fuse after the distro to the amp instead of before. IMO

 

[mat3833 10+ year member]

well ****, now i need 5 inline fuses. 1 for the Big 3, 1 in the engine bay for the power wire, one just before the distro, and 1 for each amp. god you guys make me spend money! lol, need 3 0GA and 2 4GA. anyone have a suggestion for a good quality inline fuse? id prefer them all to be weatherproof and secure.

Matt

 

[sacsking916 5,000+ posts]

well ****, now i need 5 inline fuses. 1 for the Big 3, 1 in the engine bay for the power wire, one just before the distro, and 1 for each amp. god you guys make me spend money! lol, need 3 0GA and 2 4GA. anyone have a suggestion for a good quality inline fuse? id prefer them all to be weatherproof and secure.
Matt

like i said, if it was me i would do after the distro in between to the amps.

so you should have

alt to battery

battery to distro

distro to amp 1

distro to amp 2