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Discussion Starter · #1 ·
ok I picked up my new amp today for my subs, it's a JVC KS-AX504, 320 watts RMS and 640 max. It has a 30 amp fuse, and im stuck on which gauge wiring to get. The guy I know at Canadian Tire said all I need is 8 gauge, but the guy I talked to on the phone at Electronic Depot said i need 4 gauge because it's a big amp. So I'm stuck on what gauge wiring to buy. Also 4 gauge is $3 per foot, whereas 8 gauge is $1.50, so obviously i want to go with the 8 gauge if I can =P

Sorry for the long post, but I also have another question. Is there anywhere i can run the wiring through the firewall without having to drill a new hole, on the driver's side? I ran my old amp off of the fusebox since it only had a 5 amp fuse but obviously i can't do that anymore.

Thanks,
Chris
 

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Discussion Starter · #2 ·
I've decided that I'm just gonna drill a new hole and put a grommet in the firewall, right beside the cable for the hood latch. But I'm still stuck on which wiring to buy. Also should I put a fuse on the wire beside the battery, or not worry about it since there's a fuse on the amp?

Thanks
 

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If there's a fuse along the line, you shouldn't have to worry about putting a second one on.
 

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Based on the amp specs you listed, your amp is going to draw about 60 Amps of current. 8 gauge wire will be just fine for this. You dont need to go up to 4 gauge until its drawing over 80 amps.
 

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Discussion Starter · #5 ·
Thanks, you're the first one to tell me to go with 8 gauge. But if there's a 30 amp fuse on the amp, how can it draw 60 amps??

Thanks for helping me out
 

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Well, there are multiple equations you can use to figure this. The one I used last night was not really a good example since it relied on the fuse in the amp. A better equations is to take your total RMS power (320), multiply that by 2, then divide by 13.8 (system voltage) That puts you at about 46 amps. Still a good candidate for 8 gauge. That means you should put a 40 - 50 amp fuse inline on the power cable. Not sure why this number is bigger than the amps fuse...

Here is a cable selection chart
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Jason Bradwell
Webmaster, V6Z24.com
1992 Cavalier Z24
 

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For the wiring of a car id suggest the 4 gauge. the higher the gauge the more power your amp will recieve. ALL WAYS PUT A FUSE ON ANY THING THAT YOU PUT ON THE BATTERY!! ive blown more amps then anyone here (i got a total of 7 blown amps sitting on a shelf because i thought that a fuse in the amp would stop it from popping **WRONG**) its much safer if you put a fuse just after the battery (i recommend at least a 20 for 12 gauge, and a 60 for 4 gauge) and that way there is no danger of blowing anything anywhere and if the wire for some reason makes it to ground in your car the fuse will blow before it blows your amp or even worse starts a fire.
 

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And,

when you're putting the fuse in on the line, try to put it in as close to the battery as possible..
 
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