ANL fuse size???

[king ranch 5,000+ posts]

How do you choose exactly what size of fuse is right, i came across some threads where people say you fuse for the amp draw of the amps others say you fuse for the size of the wire, so which one is it.

I am using 300amp fuses for my 1/0 from my front battery to back battery using knu klmx wire is that fine or should i drop to a 250amp fuse, then from my back battery to my zx1500 i am using kicker 1/0 with 300amp kicker fuse is that too big?? then for my zx850.4 i am running 4 gauge from my back battery with a 150amp fuse i think thats about right.

So is the 300amp fuses too big and why is it bad to have too big of a fuse, i searched and shows 1/0 wire is capable of 350amps but some say you fuse for your amps not your wire.

So which is it fuse for wire or amps??

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[jco1385 5,000+ posts]

fuse for the wire. the 300a between the batteries is fine. just make sure there is a fuse at the front AND the back battery. and i'd drop to a 150a for the amp.

thats exactly how i have mine.

edit* if the fuse is too big, it defeats the purpose of the fuse.

 

[king ranch 5,000+ posts]

yea i have fuses by the back and front battery and a fuse on the 4 gauge for my zx850.4 is 150anl and the fuse for my zx1500 is 300 prob should drop that to 200 or so

 

[king ranch 5,000+ posts]

polls up see how many people fuse for the size wire or for the draw of the amps

 

[LOW ET 10+ year member]

can someone shed a little more light on this subject.

i'll be installing my new setup soon.

i'm running 1/0 from the battery to the trunk, going into a distribution block which then will use 4awg from the distribution block to the amp. (hd600/4 only needs a 50amp fuse)

so how would one fuse that?

 

[ultimate157 5,000+ posts]

can someone shed a little more light on this subject.
i'll be installing my new setup soon.

i'm running 1/0 from the battery to the trunk, going into a distribution block which then will use 4/0 from the distribution block to the amp. (hd600/4 only needs a 50amp fuse)

so how would one fuse that?

300A at the front battery. and 4 gauge is NOT 4/0. 4/0 is massive.

 

[nimrod 10+ year member]

Well, first of all you have to figure out what your amp draw will be and size your wire accordingly. Once you have your proper wire size, THEN you size your fuse to the WIRE ampacity. You do not want to put a fuse in that can handle more amperage then the wire, because if there is a problem, then the wire could heat up and start a fire before the fuse would blow. You can put a fuse in that is rated LESS than the wire , but never more than the wire.

 

[LOW ET 10+ year member]

300A at the front battery. and 4 gauge is NOT 4/0. 4/0 is massive.

fixed for you

4awg going to amp

 

[LOW ET 10+ year member]

Well, first of all you have to figure out what your amp draw will be and size your wire accordingly. Once you have your proper wire size, THEN you size your fuse to the WIRE ampacity. You do not want to put a fuse in that can handle more amperage then the wire, because if there is a problem, then the wire could heat up and start a fire before the fuse would blow. You can put a fuse in that is rated LESS than the wire , but never more than the wire.

so when using both 1/0 and 4awg in the same run i would assume you would fuse to the 4awg rating or do you need to run a fuse at the battery then fuses after the distribution block?

 

[ultimate157 5,000+ posts]

so when using both 1/0 and 4awg in the same run i would assume you would fuse to the 4awg rating or do you need to run a fuse at the battery then fuses after the distribution block?

I fused my 1/0 at the front battery, and didn't fuse after the distribution blocks. You can fuse if you like, but the runs from my D-blocks to the amp were really short and I wasn't going to worry about it.

 

[Buck 5,000+ posts]

If your distro block goes from 1/0 to 4 gauge, you could fuse it but it's not really necessary unless the run of 4 gauge is long.

 

[nimrod 10+ year member]

so when using both 1/0 and 4awg in the same run i would assume you would fuse to the 4awg rating or do you need to run a fuse at the battery then fuses after the distribution block?

Correct, fuse at the #4AWG rating. If you are feeding multiple amps, and the main inline fuse that was rated for the #4 wire won't hold the load, then you may want to fuse to the 1/0 rating (at the battery), and then use a fused distribution block so that each # 4 wire has its own fuse. Better safe than sorry.I don't care how long the #4's are, If a problem does arise, it dosen't take long for the wire to get EXTREMELY hot and start a fire.