Size of fuse?

[Puppet Master 10+ year member]

How do I tell what size of inline fuse I should use when wiring up an amp? Does it have to be more or less than some other factor in the setup?

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[JimJ 5,000+ posts]

Should be fused to protect the wire in case of a short...so you want something that will blow before the wire exceeds its maximum current rating.

 

[Puppet Master 10+ year member]

so if I used 4 gauge wire, how big of a fuse would i need?

 

[05AztecRed 10+ year member]

125 A is large enough.

 

[Elton 10+ year member]

should be about the same as the ones on the amp like if you amps has two 40amp fuses then the inline should be the same

 

[profundus-sanus 10+ year member]

125 A is large enough.

that is what size i would reccomend.

you should only fuse to protect the amp if it has no internal fusing. So as long as the wire is adequate for the amp the amp shouldn't considered in fuse size.

 

[n2audio 5,000+ posts]

that is what size i would reccomend.
you should only fuse to protect the amp if it has no internal fusing. So as long as the wire is adequate for the amp the amp shouldn't considered in fuse size.

I disagree. If the power wire is capable of supplying a lot more current than the amp needs it makes sense to fuse the wire closer to the amp's max current draw.

For example - running a 600w (60A) amplifier with 4 ga wire. 125A fuse would be fine, but I would suggest something 60-80. The reason being if there ever WERE a problem - there would be a much higher factor of safety with the smaller fuse vs a big one.

 

[profundus-sanus 10+ year member]

I disagree. If the power wire is capable of supplying a lot more current than the amp needs it makes sense to fuse the wire closer to the amp's max current draw.
For example - running a 600w (60A) amplifier with 4 ga wire. 125A fuse would be fine, but I would suggest something 60-80. The reason being if there ever WERE a problem - there would be a much higher factor of safety with the smaller fuse vs a big one.

The fuses on the amp would still blow, unless its a pos amp.

But i guess i should have said it isn't required but Some may suggest it. You do have a valid point.

 

[bri487 5,000+ posts]

I disagree. If the power wire is capable of supplying a lot more current than the amp needs it makes sense to fuse the wire closer to the amp's max current draw.
For example - running a 600w (60A) amplifier with 4 ga wire. 125A fuse would be fine, but I would suggest something 60-80. The reason being if there ever WERE a problem - there would be a much higher factor of safety with the smaller fuse vs a big one.

the fuse under the hood is to protect the WIRE. a fuse in front of the load is to protect the load. 4 gauge can carry a maximum of 135 amps, so fuse it at that.

 

[ultimate157 5,000+ posts]

should be about the same as the ones on the amp like if you amps has two 40amp fuses then the inline should be the same

So very wrong

the fuse under the hood is to protect the WIRE. a fuse in front of the load is to protect the load. 4 gauge can carry a maximum of 135 amps, so fuse it at that.

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