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Wire/Fuse Guide

Guest SyKo13

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12 hours ago, audiofanaticz said:

Buy a DC clamp meter, clamp your power wire and see what the max draw is when your stereo is full tilt. Fuse for as close to that as possible.

If you pull 180 amps use a 200 amp fuse.

If you pull 210 amps, a 200 amp fuse will still probably work just fine.

Or just buy a a few different size fuses. Instead of buying a 300 amp buy a 200 amp and a 250 amp, maybe a 300 amp if you think you will need it.

But start small with a 200 amp fuse, if it blows use a 250 amp fuse. If the 200 amp fuse never blows just leave it installed and your good to go.
Clamp meters can be very useful in the car audio industry for anyone that dicks around a lot, and you can get a halfway decent one from the craftsman professional line for $60ish use or $125-150 new.


Ok so the most precise way to go about it and be exact is to use a meter THEN fuse it just slightly above ur max draw? That way if anything wierd happens and it starts to draw more then it did at max, hopefully ur closely rated fuse will blow? That does make more precise work of it. 

Would one of the smd tools be able to do this? Like the DD-1+? Or maybe the amm-1?

also is there a brand of fuses that are known to work as its rated? Like blow when its supposed to, or atleast closer than most others.

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6 hours ago, srp365 said:


I didn't tell anyone to run it that way, and I didn't say you were wrong, or tell you your info was "wack", but also I see it a different way. smaller fuses are going to have more resistance than a larger fuse. That's current limiting. May not be much, but it's current limiting. Now in the real world, if there's any real short circuit, either a cut in the insulation, or a wire pops out of the terminal on the amp, the current going through, even 500A on 1/0, isn't going to make the wire heat up enough to be an issue before the fuse blows... Still safe, in it's own context.

This is how it was explained to me, by Ray, and confirmed by a few other people I'd consider experts in the field. 


I purposefully didn't go on a rant before because opinions are different, even yours, and everyone gets so butthurt in here when your opinion misaligns in the tiniest way.

I can see why VS threads aren't allowed lol

A smaller fuse having more resistance is a myth, if your not pulling 300 amps of current through a wire than using a smaller fuse will not cause resistance.

I know that is something extremely hard for some people to wrap their brain around.

So for example if your piece of 1/0 wire has only 200 amps of current traveling from point a to point b, than using a 250 amp fuse, or even a 220 amp fuse will not limit anything or cause resistance, putting a 300 amp fuse in the wire will do nothing!

I have 18 runs of 1/0, 9 of which are power and fused at 120 or 150 amps.

2 s3400s under the hood, 3 DC Power 390xps, 4 5krms amps ran at .35 ohms each, 5 d3100s in the rear.

Never blew a single fuse.



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I can wrap my head around it just fine. And I'm sure your fusing is just fine. Running CCA is a personal preference. Using an oscope vs a DD1 is a preference.

I can disagree without getting bent out of shape, its cool. 

I will still fuse for the wire. Added resistance isn't a myth, that I disagree with. It may only add up to hundredths of a volt difference, but the coat of a fuse is the same for 125A or 300A. 

If you fuse for the wire, the wire is protected from conducting enough current in a short-circuit situation to cause a fire.

With multiple runs like you're doing, you are spreading the loss of resistance quite a bit, so the impact isn't as high than with guys running single runs (me and most of us) and I'm fighting to get as much current to my amps as possible.

You have your reasons for fusing the way you do, and that's fine. But I'm not wrong in the way I fuse.

2007 Pacifica
Rebuild. Less quiet. Still not loud.

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