Fuse for power wire

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Aug 27, 2007 | 01:50 AM

Vette-kid

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Melting Slicks

Joined: Oct 2006

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From: Navarre FL

Fuse for power wire

Im running two amps, a JL 300/2 and a Kenwood Excelon KAC-X10D (rated at 600WRMS). I have a 4 ga. running from the battery into a fused distro block and seperate 8ga wires to the amps. My question is, Do I need to have a 3rd fuse on the 4ga wire near the battery? And what size is appropriate for the distro block? I have 55amp fuses in it now.

Aug 27, 2007 | 02:01 AM

Kale

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Joined: Feb 2000

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From: Sacramento CA

You MUST have a fuse within 12" of the battery. For 4 gauge, 115 amp fuse would be fine.

This fuse protects the wire. Otherwise, you short that wire out, it's car fire time.

Aug 27, 2007 | 02:15 AM

Vette-kid

Thread Starter

Melting Slicks

Joined: Oct 2006

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From: Navarre FL

Wow, glad I asked! So are the fuses at the distro block still necassary, will they be ok to leave in if not (so I dont have to pull that out...more work

)

Aug 27, 2007 | 02:27 AM

Kale

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Joined: Feb 2000

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From: Sacramento CA

Quote:

Originally Posted by Vette-kid

Wow, glad I asked! So are the fuses at the distro block still necassary, will they be ok to leave in if not (so I dont have to pull that out...more work

)

Yes.

You must fuse every time you have a power wire size reduction.

Otherwise the small wire might /become/ the fuse.

Aug 27, 2007 | 02:34 AM

Vette-kid

Thread Starter

Melting Slicks

Joined: Oct 2006

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From: Navarre FL

Got it! Sounds like you saved me from some major headaches later. Is there a formula or even simpler, a website, for finding the right fuse size? It should be based on the wire size right? Thats what your protecting, not the amps...right?

Aug 27, 2007 | 08:48 AM

BAND1T

Burning Brakes

Joined: Aug 2000

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From: Colorado

Quote:

Originally Posted by Vette-kid

Is there a formula or even simpler, a website, for finding the right fuse size? It should be based on the wire size right? Thats what your protecting, not the amps...right?

The fuse is used to protect both - either to protect the power source which includes the wire that connects the power supply to the electrical device, or to protect the electronic equipment.

Suggested Fuse Sizes:

Wire Gauge Recommended
Maximum Fuse Size
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

These are the recommended maximum fuse ratings for the corresponding wire size. Using a smaller fuse than what's recommended here will be perfectly safe.

(courtesy from BCAE)