i have a question about fuses....

[gnatnoop 10+ year member]

so i was doing the big 3 earlier today and i was telling my dad about it.. and i told him im going to run a 300 amp fuse between the alt and battery (i have a new 200 amp alt.) and he told me that i need to get a fuse that is 200 amp or less... is this correct?? (my dad has been a mechanic for 35 year btw).. but for some reason (reading on here) i think he may be incorrect.. help?

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[lantz 10+ year member]

depends on what size wire you are using.

i use 250 but 300 would be fine....he's probably matching the fuse with the alternator but the fuses are really meant to match the size wire you are using.the fuse sizes listed are the biggest you can use for the wire specified.anything bigger would be like having no fuse at all.make sure you fuse the wire close to the battery and not the alternator.that way the battery cant continue to discharge through the length of the wire if something happens.

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.

 

[Varinabassing 10+ year member]

I wouldnt go less but 200 amp should be fine your alt can only put that out max so it wouldnt hurt i would still run 250 just because doesnt cost more and to me seems ike you get cooler flow but some of the guys on here may know better

 

[gnatnoop 10+ year member]

ok, i have another question for you guys....

if i get this kit.. http://www.knukonceptz.com/productDetail.cfm?prodID=KFX-PK20

which fuses should i get if i am running about 900-1100 rms

 

[gnatnoop 10+ year member]

bump..

 

[lantz 10+ year member]

use a 250 or 300 amp fuse for any 1/0 wire you run,regardless of how many watts you have.

 

[91Chevy 10+ year member]

Fuse based on the wire, not the system.

 

[jpexpc 10+ year member]

If you read what they are telling you then you would realize they answered your question 6 posts ago.

 

[gnatnoop 10+ year member]

use a 250 or 300 amp fuse for any 1/0 wire you run,regardless of how many watts you have.

Fuse based on the wire, not the system.

If you read what they are telling you then you would realize they answered your question 6 posts ago.

my new question was what fuses should i be running at this fuse block... http://www.knukonceptz.com/productDetail.cfm?prodID=KNF-12 for a system that is 900 watts rms- 1100 watts rms.. and i dont see 250 amp //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[KyleBechtold 5,000+ posts]

use a 250 or 300 amp fuse for any 1/0 wire you run,regardless of how many watts you have.

wrong.

 

[KyleBechtold 5,000+ posts]

Fuse based on the wire, not the system.

you too

 

[gnatnoop 10+ year member]

lol, who is right

 

[smoka 10+ year member]

use a 250 or 300 amp fuse for any 1/0 wire you run,regardless of how many watts you have.

Fuse based on the wire, not the system.

Sorry guys, but I disagree.

If you know what the max continuous load is, then you fuse to protect the equipment.

Here is how you calculate your fuse size:

You take your max continuous load, which is 200a in the example above. Multiply that times 20% to get your correct fuse size. So you would use a 240a (or 250a) fuse for the above example. 20% is a 'rule of thumb' that electricians often use. (the details can get pretty technical)

If your correct fuse size is less than the max ampacity of the wire, then use it. If its higher, then you need to upgrade your wire.

Between the alt to batt, and amps to batt, you can easily calculate the fuse ratings, so why would you oversize it?

 

[jpexpc 10+ year member]

Sorry guys, but I disagree.
If you know what the max continuous load is, then you fuse to protect the equipment.

Here is how you calculate your fuse size:

You take your max continuous load, which is 200a in the example above. Multiply that times 20% to get your correct fuse size. So you would use a 240a (or 250a) fuse for the above example. 20% is a 'rule of thumb' that electricians often use. (the details can get pretty technical)

If your correct fuse size is less than the max ampacity of the wire, then use it. If its higher, then you need to upgrade your wire.

Between the alt to batt, and amps to batt, you can easily calculate the fuse ratings, so why would you oversize it?

Your equipment has fusing to protect it. The inline fusing is so you can enjoy your car not being on fire for as long as possible. Why buy 1/0 wire and fuse it at 125A? Think about it. Fuse the wire...............

 

[smoka 10+ year member]

my new question was what fuses should i be running at this fuse block... http://www.knukonceptz.com/productDetail.cfm?prodID=KNF-12 for a system that is 900 watts rms- 1100 watts rms.. and i dont see 250 amp //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Power = Current * Voltage

1100 watts / 13.8v = 80 amps