Big 3 Fuse

[texicanz 10+ year member]

i am doing the big 3 steps and i wonder if its ok to put a 80a fuse on a jeep grand cherokee 90 amp alternator

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[PaulThompson229 10+ year member]

If the alt really puts out 90A it will probably pop the fuse, and while it is reccomended fusing in the big 3 is not nessacary, I don't do it with 0 problems.

 

[Buck 5,000+ posts]

The only way I see that you could have a problem with fusing the big 3 is if you had more current than the wire could handle. Say if you have 0 gauge, and a 200 amp h/o alt. Most 0 gauge is rated at 300a, so I don't see a way that you could possibly have a wire catch on fire, expecially with that short of run. Not unless you have a 300a+ alt.

 

[boomzilla 10+ year member]

You fuse that wire with what amps/ voltage the actual wire can carry, not the alternator. If you're using 1/0 wire use a 200-250 amp fuse. Some people don't do this, which can lead to your car on fire if anything bad happens.

 

[PaulThompson229 10+ year member]

You fuse that wire with what amps/ voltage the actual wire can carry, not the alternator. If you're using 1/0 wire use a 200-250 amp fuse. Some people don't do this, which can lead to your car on fire if anything bad happens.

Agreed, which is why it is reccomended, and most 1/0 is rated at 300A not 200A.

 

[Buck 5,000+ posts]

You fuse that wire with what amps/ voltage the actual wire can carry, not the alternator. If you're using 1/0 wire use a 200-250 amp fuse. Some people don't do this, which can lead to your car on fire if anything bad happens.

I realize that, but as far as the alt goes I don't see how anything can happen to the wire if the amperage of the alt is less than what the wire can handle.

 

[aturcotte127317 10+ year member]

I realize that, but as far as the alt goes I don't see how anything can happen to the wire if the amperage of the alt is less than what the wire can handle.

yea that is what i was thinking....

 

[texicanz 10+ year member]

well my old stock wire to the alternator did not come with a fuse so i was wondering if i can add another 4 gauge at the postive of the alternator attachin to the old stock wire and run the new 4 gauge with a fuse seprate way to the battery and leave the old stock wire where it was with no fuse and heres a picture link to show you what i am kind of talking about

http://i480.photobucket.com/albums/rr162/hifonics98/jeep_grand_cherokee_engine.jpg

 

[NoSq 10+ year member]

If the stock thin ass wire hasn't burned up yet, i highly doubt the thicker one your putting on will.

 

[dman4486 5,000+ posts]

well my old stock wire to the alternator did not come with a fuse so i was wondering if i can add another 4 gauge at the postive of the alternator attachin to the old stock wire and run the new 4 gauge with a fuse seprate way to the battery and leave the old stock wire where it was with no fuse and heres a picture link to show you what i am kind of talking abouthttp://i480.photobucket.com/albums/rr162/hifonics98/jeep_grand_cherokee_engine.jpg

Pic shows you running wires to the Air Conditioning Compressor......This will not help:fyi:

 

[texicanz 10+ year member]

Pic shows you running wires to the Air Conditioning Compressor......This will not help:fyi:

i know that because the alternator is under the ac compressor and could not show it in the picture

 

[dman4486 5,000+ posts]

i know that because the alternator is under the ac compressor and could not show it in the picture

as long as you realize this....//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

If you are worried about Fusing, then there should be a fuse between any power source(batteries/alternator) and a potential grounding situation. I did not fuse my big 3 and have had no issues, but I also have not been in a wreck and ran my wire such that it did not have any chance of being pinched and grounded.

And the fuse is intended to protect the wire....So fuse according to wire gauge being run.

 

[loopkiller 10+ year member]

The stock wire is effectively a fuse due to how thin it is. The manufacturer never used a fuse because the wires they run are out of the way of any moving object. They also assume that if you get in a crash that might cut that wire, the engine will stop running anyways. That wire coming from your alt usually goes directly to the fuse box, then to the battery. So if the engine is not running due to the crash, and then the wire is grounded, the fuse will pop due to the battery supplying the current.

Cliffs, to be safe, always fuse any POS+ wire you add. It is a $10 insurance policy. Fuse based on wire rating.

 

[05AztecRed 10+ year member]

I realize that, but as far as the alt goes I don't see how anything can happen to the wire if the amperage of the alt is less than what the wire can handle.

Its fused for any electrical SURGES that MIGHT happen...

ANY wire, nor matter WHAT size, can have a HUGE momentary surge that will overheat the wire and start an electrical fire which is VERY difficult to put out...

 

[texicanz 10+ year member]

as long as you realize this....//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

If you are worried about Fusing, then there should be a fuse between any power source(batteries/alternator) and a potential grounding situation. I did not fuse my big 3 and have had no issues, but I also have not been in a wreck and ran my wire such that it did not have any chance of being pinched and grounded.

And the fuse is intended to protect the wire....So fuse according to wire gauge being run.

i am adding a new 4 gauge wire to the stock wire and the stock wire is 4 gauge and in my car manual its says it has a 175a generator mega fuse so idk if it was removed so would it be fine if i just buy a new 175a mega fuse and add the stock wire and the new 4 gauge wire