# Big 3 Question (Wire Size)



## ssmith100 (Jun 28, 2007)

What gauge wire are you guys using to do your big three. I'm assuming 4g but are some going as big as 0g. I need to do this and have plenty of 4g to do it with. Should that be sufficient ??

Thanks,

Shane


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## tcguy85 (Oct 29, 2007)

i just did mine with 0 gauge. used the knukonceptz klm wire. 10ft and 6 ends shipped for $36 shipped to my door.


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## kyheng (Jan 31, 2007)

Depending on what type of system you are using, normally 4AWG can do the job, unless you are going very high powered system(>1000W)


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## tcguy85 (Oct 29, 2007)

my setup consists of 1220 class a/b watts. i did mine with 0 gauge. it might be overkill but there is no kill like overkill! spend the $36.


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## HondAudio (Oct 19, 2006)

What's the Big 3 again? I'm redoing my ground wires this weekend but that's something different.


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## tcguy85 (Oct 29, 2007)

HondAudio said:


> What's the Big 3 again? I'm redoing my ground wires this weekend but that's something different.


simply a big wire from battery positive to alt positive, a big wire from battery negative to frame, and then one from the engine to the frame. thats it!


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## HondAudio (Oct 19, 2006)

All I need is the wire from the alt to the battery then. I have my engine and battery grounded together and to the frame in multiple spots


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## BLD 25 (Apr 13, 2007)

4ga is usually enough for most people i would assume. i mean my car looks like it was 8ga stock, so now when you have both, that is far better, especially on such short distances. Remember that wire can carry almost exponentially more current and amperage the shorter the distance, so over 3 feet, 4 is usually enough, especially if you already have it.


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## Fixtion (Aug 25, 2006)

*wire.sizes*

*statement*

check specifications of your eletrical system: 

+*alternator output [amps]*
+*battery output [amps]*
+*ampacity of copper wire*

electricity is fun!


*example*

volkswagen rabbit specifications:

+alternator *140*amp
+battery *60*amp

according to this chart: http://www.wiktel.com/standards/ampacit.htm

+*8awg* is rated at *60amps* @140 F close to engine bay temps. this can be derated further due to heat.

but our biggest power supply is 140amps, supplied from the alt.-to-bat.!

+*2awg* is rated at *140amps* @ 140 F

so what do we do?


*solution*

for the purposes of the *big3* buy wire based on the alt. output [amp rating]. this will ensure max/consistent amperage to the battery.

even though the battery will only ever release 60amps, making certain 140amp reaches the battery is most benificial.


*futher.calculations*

you can calculate amperage drawn from your system:

http://www.sengpielaudio.com/calculator-ohm.htm

*inputs* [constants]

+ohm rating
+target wattage

*ouputs* [variables]

+voltage to achieve for target wattage
+amperage drawn.

*example*

*system*

+*zapco dc reference 1000.4* x 2
150w x 4
500w x 2

+*hiquphon owii*
-8ohm
-75w target

+*scanspeak 12m/4631g*
-4ohm
-40w target

+*peerless 830491* _xls 8_
-8ohm
-75w target

+*diyma 12"*
-4ohm
-500

*owii *= 24.50v @ 3.00A

*12m *= 12.56v @ 3.00A

*830491 *= 24.50v @ 3.00A

*diyma12 *= 44.72v @ 11.00A

*total amperage draw* 20.00A @ 880w !!!

i only need *12awg* or even as low as *14awg* run to my amps!

i would go with 14awg b/c deratting happens due to heat and other factors.

my systems wire is taylored specifically to my demand.

*benefits*

+*cost*
+*flexibility*
+*techflex **size*
+*efficiency*

*-fixtion*


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## ZoNtO (Sep 20, 2005)

Wouldn't it make more sense to fuse to the total amount of your amp fuses for redundancy? Say for instance in my situation I'm planning on using an eD nine.5 which has a 120A fuse, but eD recommends 0 gauge wire. The amp won't ever need to see 250A so why not just set it for the same amount?


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## 89grand (Nov 23, 2006)

0 guage wire is ridiculous for that amp. If that's what ed recommends, they're insane. You're only fusing to protect the car from the wire buring up incase of a short. Just use a fuse that's large enough not to blow from normal operation of the amp. Using the amps fuse rating makes sense.


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## ZoNtO (Sep 20, 2005)

89grand said:


> 0 guage wire is ridiculous for that amp. If that's what ed recommends, they're insane. You're only fusing to protect the car from the wire buring up incase of a short. Just use a fuse that's large enough not to blow from normal operation of the amp. Using the amps fuse rating makes sense.


Well not really if you think about it. They give you headroom and good advice for solid operation. Bridging the two front channels and with a 1 ohm load on the sub it would be over 1300W at 12.5v. Assuming a 15-17 foot wiring run, 0 awg would make sense in that case wouldn't it?

Those little charts based on wire length and power run really are quite helpful, and for the majority of installs that I've checked on they recommend 2 gauge for optimum results which basically means 0 awg from an availability standpoint.


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## 89grand (Nov 23, 2006)

The problem I have with those charts and the people recommending huge wire is that even if this 5 channel amp _could_ produce a total of 1300 watts...it never will while listening to music. I'd be willing to bet that even during what is perceived as loud peaks, the amp isn't drawing even half of the maximum current it could. 

About the only way to get the amp to draw that much current would be to play pink noise at maximum volume.


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## ZoNtO (Sep 20, 2005)

That's true, I guess I do overlook that fact quite often. Still for those rare occasions when we demo pink noise to our friends, 0 awg is teh gr8est!11!


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## Fixtion (Aug 25, 2006)

Autiophile said:


> You just calculated required wire sizes for your speaker wire, not your power wires to the amplifiers. At no point did you take into account the efficiency of the amps or the voltage input to the amplifier.
> 
> Example, your 500 watts going to the subwoofer will require 590 watts of input power (assuming class d efficiency around 85% which is pretty good). That would require 40.8 amps @ 14.4 volts.
> 
> ...


*statement*

all target wattage is maxed. amps are pushed to limits.


*controlled.limits*

+ohm rating
+amps power rating


*adjustment.calculation*

i adjusted my calculations to 13.6v; which is more realistic.

and the total amerage is 64.71A

falls under 6awg wire @ 80A

i'm currently running 4awg, so i'm fine.

thanks for pointing out my methods. that's why i love the forums.

*-fixtion*


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## ssmith100 (Jun 28, 2007)

Well,

Guess I'm going to order some 0 Gauge and some ends for my big three. I know if I do the 4 gauge I'll always wonder "what if" if i had done the 0.

Shane


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## HondAudio (Oct 19, 2006)

I don't see the harm in doing the biggest wire possible. Think of it this way: One day I hope to be the architect for my own house. One of the things I'm going to specify is that the pipes be extra large, so they don't get clogged. 

Just think about that. You won't ever need to call a plumber


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## 89grand (Nov 23, 2006)

HondAudio said:


> I don't see the harm in doing the biggest wire possible. Think of it this way: One day I hope to be the architect for my own house. One of the things I'm going to specify is that the pipes be extra large, so they don't get clogged.
> 
> Just think about that. You won't ever need to call a plumber



While there is some logic to this thinking, it really depends on whether you see yourself running a lot more power in the future.

I usually know pretty much what I'm going to be running when choosing power wire and such and never anticipate drastically changing things.

0 gauge wire also costs a lot more than say 4 gauge so it's wasted money for those that don't need it. It's also a ***** to run through the car too.


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## tcguy85 (Oct 29, 2007)

^^^ funny post. lol


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## t3sn4f2 (Jan 3, 2007)

Autiophile said:


> I know. I'm an engineer, I can't help it.


Sounds like you know your _****_


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## rockondon (Jan 18, 2008)

t3sn4f2 said:


> Sounds like you know your _****_


Now thats funny.


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## HondAudio (Oct 19, 2006)

t3sn4f2 said:


> Sounds like you know your _****_


Yes, I happened to bring this up because recently I had a _****-clog_ in the toilet. It was somewhere out of sight, possibly in the toilet's s-bend or where it met the floor. Plunging was useless. I had to get a snake :blush:


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## Fixtion (Aug 25, 2006)

HondAudio said:


> Yes, I happened to bring this up because recently I had a _****-clog_ in the toilet. It was somewhere out of sight, possibly in the toilet's s-bend or where it met the floor. Plunging was useless. I had to get a snake :blush:


that *****s* gross. . . lol

*-fixtion*


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## Oliver (Jun 25, 2007)

Saw a "Honey sucker" driving thru town with the name "Security Septic" on the side.

There motto popped into my head , or actually what I thought it should be..."We keep your **** to ourselves"


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## Oliver (Jun 25, 2007)

WOW, talk about **** going down !!


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## t3sn4f2 (Jan 3, 2007)

Autiophile said:


> You haven't lived until you've seen a turd the size of a ferret get stuck on a bar screen at a municipal treatment plant.
> 
> *Occasionally bodies get stuck on the bar screens in some rougher areas. Some operators also listen to police scanners so they can retrieve baggies of drugs and cash that get flushed during raids.*



No ****?! 






lol


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## Fixtion (Aug 25, 2006)

*aight!*

this ****s got to stop!

*seriously.*

bwhahahah, we're so ot.

**

*-fixtion*


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