Which fuse do I need

[Kfra315 10+ year member]

I am running 900w RMS on 4 gauge wiring. I need a fuse that can handle that much wattage since a few shops I went to told me the glass 80 amp fuses can overheat on that much power. What kinda fuse do you guys recommend and also what amperage fuse do I need for the power I'm running?

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[ShakesAllDay 10+ year member]

100-150 amp ANL

 

[ShakesAllDay 10+ year member]

Wrong. Check the amps fuses on the side if it has any. There may be like 3 30A fuses, 3 40A fuses, etc. Add those up and thats the size ANL you need for your inline fuse. Look at knukonceptz.com. If it doesnt have fuses on the side read the manual and it should say

Excuse me? What do the fuse sizes on the amp have to do w/ anything? Protecting the wire here, not the amp(s).

 

[Rich B 5,000+ posts]

Excuse me? What do the fuse sizes on the amp have to do w/ anything? Protecting the wire here, not the amp(s).

X2

But 4 ga should be no more than 125a I believe.

My Kicker 4ga kit came with a 100a fuse, and I believe the Knu kits come with 125a.

 

[ShakesAllDay 10+ year member]

X2
But 4 ga should be no more than 125a I believe.

My Kicker 4ga kit came with a 100a fuse, and I believe the Knu kits come with 125a.

Yeah, I believe *max* to be 150 amps for 4-ga. I would shoot lower just to be safe.

Good reference... Fuse/wire guide

 

[ShakesAllDay 10+ year member]

Yes your wrong. 4 gauge is fine to 1400W depending on length of the wire. You use fuses to protect your amps not the wire. Your wire shouldnt be over heating as long as you use the correct gauge wire for the amount of power you are running. If he was running 2kw Id say upgrade your wire no your fuse size. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

BAHAHAHA!

You are right on one count... upgrade the wire (not the fuse) when in doubt. But, you, my internet acquaintance, need to quit spreading misinformation.

We are protecting against shorts/faults in the wire. //content.invisioncic.com/y282845/emoticons/*******.gif.a649d21efc0d1fd4890a6428166586c1.gif

 

[starkfu 10+ year member]

you always fuse at the battery to protect the wire, but you fuse at the rating of the amp, not the capacity of the wire......

If you run 4 gauge to a 90 amp rated amplifier, and put in a fuse at the battery for the wire's rating (about 150) you run the risk of blowing your amplifier if the wire shorts. Thus the fuse at the battery should be rated to the amplifiers you are running to protect them as well as the wire.

 

[ShakesAllDay 10+ year member]

The fuse rating of the amplifier(s) has no bearing on a shorted power wire.

Where do you guys come up w/ this stuff?

Amplifier fuse(s) = amplifier protection

In-line fuse = wire/battery protection

 

[starkfu 10+ year member]

The fuse rating of the amplifier(s) has no bearing on a shorted power wire.
Where do you guys come up w/ this stuff?

Amplifier fuse(s) = amplifier protection

In-line fuse = wire/battery protection

You are correct in that amplifier fuse = amplifier protection

You are correct in that In-line fuse = wire protection

Where you are wrong is how you value the size of the fuse on that in-line at the battery.

where do I come up with it? how about the MECP advanced test, you never put in more then you need.

You are still protecting the wiring, but you do it at the amps amperage rating.

 

[ShakesAllDay 10+ year member]

Where you are wrong is how you value the size of the fuse on that in-line at the battery.

where do I come up with it? how about the MECP advanced test, you never put in more then you need.rating.

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

I understand the logic, but find it unnecessary. I suppose using a fuse to handle a wire's maximum amperage is unnecessary, as well. Let's just ditch all fuses! //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif j/k

Different strokes for different folks.

 

[05AztecRed 10+ year member]

You use fuses to protect your amps not the wire. Your

INCORRECT... You fuse to protect the WIRE, NOT THE AMP. Taht is why amps have on-board fuses!

The ONLY case you would fuse down a wire is if you have a much smaller amp that does NOT have any on board fuses.

Why use a 300A fuse on a 1/0 wire to power a 100W RMS non-fused amp? The Amp would fry before the fuse popped.

 

[Kriszilla 10+ year member]

You fuse for the wire. Then again, what do I know, I'm only an electrical engineer... //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

 

[starkfu 10+ year member]

You fuse for the wire. Then again, what do I know, I'm only an electrical engineer... //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

As am I.

 

[azbass 5,000+ posts]

Wrong. Check the amps fuses on the side if it has any. There may be like 3 30A fuses, 3 40A fuses, etc. Add those up and thats the size ANL you need for your inline fuse. Look at knukonceptz.com. If it doesnt have fuses on the side read the manual and it should say

for future reference DO NOT listen to this

 

[starkfu 10+ year member]

actually, that is quite correct, you take the max current draw of all items placed on the power line and fuse at the battery for the maximum current draw of your system, not the maximum current draw of your power wire. Correct the fuse at the battery is to protect the wire, but you don't allow 150amps of current to openly feed a maximum current rated 90amp amplifier. Now I wouldn't just base this on the fuse ratings at the amp, but I would consult the owner's manual to find maximum current rating, or just use ohm's law.