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Discussion Starter · #1 ·
should I run the inline fuse holders with a 150 amp fuse within 1 foot of the battery and then fuses to match the amp fuses (80 amp for one amp and 60 amp for the other) or all three with 150 amp fuses?
[/url][/IMG] heres what my setup is gonna look like-

Should I run 8g wire from the dist blocks to the amps, or just stick with the 4g the whole way through?

Lastly, welding wire or KnuKonceptz Kolossus Fleks Kable? both are oxygen free copper, not the CCA wire. Running Knu 4g to dist and 8g from dist to amps will be $23.24 shipped, running all 4g knu wire will run me $37.94, and the 4g welding cable on ebay is $23 shipped- heres the link- Welding Cable 4 AWG 20
Price is pretty close for any of these options, all under 40$, just wondering what would be the best?

My amps, speakers, fuses and fuse holders all came in today, I went to an electronics store and picked up all of the spade connectors, so I'm getting the last of it all together- Power/ground cables, grounding terminals, and 4g battery terminal clamps are last on my list. It's getting exciting- that moment right before it becomes frustrating hahaha

Thanks again !
 

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That chart is recommended wire size for a load. The recommendation in that chart is based on voltage drop rather than ampacity. In other words, it's a chart designed around performance rather than safety. Which is fine, but fusing is a safety issue. The wire gauge you choose translates to a specific maximum fuse size. You mentioned 4ga wire... the max fuse size for that gauge is about 125A, or lower.

FUSES
 

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Getting ready to put in a new system myself and I've seen lots of different ways to go about it. The way I see it, fuses are for protection, so...

What I'm doing:

Add up all the fuse ratings of your amps.

Figure out the amp rating of your power wire.

Whichever is lower, that's the size fuse you go with. This will insure that nothing (wire or amps) burns up before the fuse does. Ideally the combined fuse total of your amps should be less than that of the wire. If it isn't, I would look at going with a bigger/better wire to get it that way. Always best to error on the side of caution! ;)
 

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Discussion Starter · #11 ·
Getting ready to put in a new system myself and I've seen lots of different ways to go about it. The way I see it, fuses are for protection, so...

What I'm doing:

Add up all the fuse ratings of your amps.

Figure out the amp rating of your power wire.

Whichever is lower, that's the size fuse you go with. This will insure that nothing (wire or amps) burns up before the fuse does. Ideally the combined fuse total of your amps should be less than that of the wire. If it isn't, I would look at going with a bigger/better wire to get it that way. Always best to error on the side of caution! ;)
This makes alot more sense than the wire website, thanks! I'll have to try to read the wire page again that wa posted earlier- thanks!
 

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It might make more sense, but it's not correct. :)

Fusing is for wiring. Period. The size of the fuse should be chosen to adequately protect your wire. For 4ga, it can be 125A. Or it can be lower. It can't be higher.

The fuses on the amps are for amps. Period. If they're fused by the manufacturer, then they're all set. That fuse rating has NOTHING TO DO with how much current that amp will actually draw under normal operating conditions. It was determined by the manufacturer to be the right size to protect it from bursting into flames. Some amps (not generally in car audio) have several fuses inside of them to protect certain circuits from taking out certain other circuits. Some even have specialty circuits that are more effective (ie. faster) than fuses for added protection. Either way, the bottom line is to ignore your amp fuses. They don't provide any useful information to you.

It's really a pretty simple concept, IMO:

1. Choose wire size based on how much current you expect the amplifier(s) to draw. This is sometimes on the spec sheet. When it's not, it can be estimated by dividing the nominal power rating by about 10 or 20 (or even more if it's a class D amp). The answer you get is already a HUGE overestimate of current requirements, so you shouldn't feel like you need to add more overkill to this number. You can if you want, but you don't gain anything.

2. Once you have decided on the wire size, go to the fuse chart on bcae1 and buy that fuse (or lower).

That's all you really have to do.
 

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Discussion Starter · #13 · (Edited)
It might make more sense, but it's not correct. :)

Fusing is for wiring. Period. The size of the fuse should be chosen to adequately protect your wire. For 4ga, it can be 125A. Or it can be lower. It can't be higher.

The fuses on the amps are for amps. Period. If they're fused by the manufacturer, then they're all set. That fuse rating has NOTHING TO DO with how much current that amp will actually draw under normal operating conditions. It was determined by the manufacturer to be the right size to protect it from bursting into flames. Some amps (not generally in car audio) have several fuses inside of them to protect certain circuits from taking out certain other circuits. Some even have specialty circuits that are more effective (ie. faster) than fuses for added protection. Either way, the bottom line is to ignore your amp fuses. They don't provide any useful information to you.

It's really a pretty simple concept, IMO:

1. Choose wire size based on how much current you expect the amplifier(s) to draw. This is sometimes on the spec sheet. When it's not, it can be estimated by dividing the nominal power rating by about 10 or 20 (or even more if it's a class D amp). The answer you get is already a HUGE overestimate of current requirements, so you shouldn't feel like you need to add more overkill to this number. You can if you want, but you don't gain anything.

2. Once you have decided on the wire size, go to the fuse chart on bcae1 and buy that fuse (or lower).

That's all you really have to do.
well why didn't you just say that?? ;);)
Okay this makes more sense. So the fusing doesnt have anything to do with the amp because the amp apready has onboard fuses, in my case the ts1440 is 2x 30A fuses and the alpine is 2x30A fuses, so they dont need any further protection, nor do these fuse rating have anything to do with the rating of the inline fuses- the inline fuses are ONLY for protecting the power wires.. it is not necessary to fuse ground wires, only the power wires, and those fuse ratings are based on what the wire can handle. those fuses have to be the same or lower amp rating than the power wire. the example on the fuse site was a 200a fuse protecting a 8g wire, in which case there is no protection because the wire would burn far before the fuse were to blow out.
On the website, it said at ANY time the wire size is reduced, you must add a fuse in the line (at the point of distribution) to protect the smaller wire. Does this mean I cant use the unfused dist blocks I purchased and use the inline fuse holders immediately after the split at the dist block? Would this be okay or do i HAVE to use fused dist blocks if im reducing size?
for the alpine 4x110=440, 440/10=44, 8AWG is rated for 52a, so 8g to this amp,
and the ts1440, rms is 720w, 720/10=72a, so the best gauge for this is 6, which is rated at 82a, right?
 

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You have to fuse the smaller wire with smaller fuses. But there is an acceptable shortcut. You could undersize your main fuse.

For example, if your main wire is 4ga and it splits to three 8ga wires, you could put a single fuse on the main line sized according to what 8ga calls for. Then you wouldn't have to individually fuse the 8ga lines.
 

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Discussion Starter · #15 ·
You have to fuse the smaller wire with smaller fuses. But there is an acceptable shortcut. You could undersize your main fuse.

For example, if your main wire is 4ga and it splits to three 8ga wires, you could put a single fuse on the main line sized according to what 8ga calls for. Then you wouldn't have to individually fuse the 8ga lines.
would this be safer than individually fusing the 2 lines after the dist block? wouldnt this "choke" the amount of power going through the 4g?
 

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would this be safer than individually fusing the 2 lines after the dist block?
can fuse the 4ga for 125A and then the individual 8ga lines at the distro or do like Mark suggested with a smaller fuse at the 4ga. you can always fuse smaller and not hurt anything.

BUT! if you fuse the 4ga wire for the 8ga distro wires. you might be under fused for total amperage draw. This wont hurt anything, but it will make the fuse on the 4ga keep blowing. you need to work that up in your design.
 

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can fuse the 4ga for 125A and then the individual 8ga lines at the distro or do like Mark suggested with a smaller fuse at the 4ga. you can always fuse smaller and not hurt anything.

BUT! if you fuse the 4ga wire for the 8ga distro wires. you might be under fused for total amperage draw. This wont hurt anything, but it will make the fuse on the 4ga keep blowing. you need to work that up in your design.
It could make it blow, but this is typically not the case.
 

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It could make it blow, but this is typically not the case.
just wanted to make sure he understood the posibility. if he is on the edge with the 8ga, then 2 8ga runs could support more current than 1 4ga. would this happen very often, no. that is why I said he needs to work out his current demands.

this is also why I jsut run the same gauge wire across all paths. makes things simpler.
 

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Discussion Starter · #19 ·
can fuse the 4ga for 125A and then the individual 8ga lines at the distro or do like Mark suggested with a smaller fuse at the 4ga. you can always fuse smaller and not hurt anything.

BUT! if you fuse the 4ga wire for the 8ga distro wires. you might be under fused for total amperage draw. This wont hurt anything, but it will make the fuse on the 4ga keep blowing. you need to work that up in your design.
okay, but is it a safety concern to fuse the 8g individually immediately after the dist block? or do I HAVE to have a fused dist block? I'd prefer to not be constantly replacing fuses
 

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Discussion Starter · #20 ·
this is also why I jsut run the same gauge wire across all paths. makes things simpler.
if this will eliminate complication i don't mind running all 4g, but if it complicates things by changing wire size then I'll just run all 4g. if i run all 4g then I only need to fuse once at 125a within 1 foot of the battery and then I'm done, right? It was suggested by another user that I should fuse multiple amps individually...
 
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