# 8 gauge power with JL 12W7 ???



## duckymcse (Mar 15, 2009)

I am currently running an Alpine V12 (400-500W rms) with JL 12W7 subwoofer. I am using 8 gauge power wire with probably about 8ft from the battery to the amp. I don't know what the fuse amp is rated. I had been running it for about 2 weeks and it work great. This setup handle the JL 12W7 quite well.
I'm getting the JL HD750 next week which rated at 750W rms to replace my Alpine V12. My question is what is the drawback or consequences if I am still using the same 8 gauge power on this new amp?
Will it:
1. Damage the amp or subwoofer
2. Performance will not be at it potential
3. It should work fine

I really hate to change the wire to 4 gauge if it is unnecessary due to cost and labor.


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## JayinMI (Oct 18, 2008)

ABSOLUTELY upgrade. The 750's have a thirst for current. I've had some issues with some of the ones we've installed. Make sure you put a fuse near the amp as well as at the battery. ANd keep an eye on the power plug, they melt sometimes.

Jay


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## Wheres The Butta (Jun 6, 2009)

x2 ^ 

use 4ga


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## duckymcse (Mar 15, 2009)

Yeah, I do have a fuse between the battry and amp. I'm not sure what amp the fuse is rated at.
Melt? Now that is scary. Look like I better upgrade to 4 gauge power wire.
Thanks for the advice.



JayinMI said:


> ABSOLUTELY upgrade. The 750's have a thirst for current. I've had some issues with some of the ones we've installed. Make sure you put a fuse near the amp as well as at the battery. ANd keep an eye on the power plug, they melt sometimes.
> 
> Jay


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## 60ndown (Feb 8, 2007)

run another 8 guage...or 2 more.


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## fredridge (Jan 17, 2007)

actually, you really don't need to upgrade your power wire if that is the only amp you are running...at 8ft it will be fine.

go here WIRE and then about halfway down is a calculator you can use to find out it is enough.

Looks like 8 guage at 8 feet on a 75% efficient amp is good to 1000 watts


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## 60ndown (Feb 8, 2007)

fredridge said:


> actually, you really don't need to upgrade your power wire if that is the only amp you are running...at 8ft it will be fine.
> 
> go here WIRE and then about halfway down is a calculator you can use to find out it is enough.
> 
> Looks like 8 guage at 8 feet on a 75% efficient amp is good to 1000 watts


or that ^ :blush:


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## bassfromspace (Jun 28, 2016)

The real question is who has an amp that's 75% efficient.

I'd upgrade the cable as a precaution.


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## Oliver (Jun 25, 2007)

From basic car audio and electronics>

.................................class AB....class D

8 awg....	52 amps....	430 watts....	537 watts


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## Wheres The Butta (Jun 6, 2009)

a$$hole said:


> From basic car audio and electronics>
> 
> .................................class AB....class D
> 
> 8 awg....	52 amps....	430 watts....	537 watts



gotta love this guy.


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## Oliver (Jun 25, 2007)

If he supercools the wire in it's entirety it should be fine , even as the voltage drops and the current flow increases , if it is just one wire he doesn't have to derate it and with liquid nitrogen surrounding the wire he can actually add a bit to the flow rating.

N.E.C. once you have read the various sections on the insulation type on your wire and the ambient temps recommeded are followed for ideal ratings you'll be fine when the amp is at 1/4 to 1/3 volume and the efficiency has dropped to 15% or 25% of its ideal number that is always quoted . . .

750 watts at 14.5 volts , etc..,


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## duckymcse (Mar 15, 2009)

Hmm...I am really thinking of trying with the 8 gauge first and see how it handle the JL HD750. I think it might handle fine, but the question is there any sound quality different when using 4 gauge vs 8 gauge?




fredridge said:


> actually, you really don't need to upgrade your power wire if that is the only amp you are running...at 8ft it will be fine.
> 
> go here WIRE and then about halfway down is a calculator you can use to find out it is enough.
> 
> Looks like 8 guage at 8 feet on a 75% efficient amp is good to 1000 watts


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## duckymcse (Mar 15, 2009)

Not a good idea for me since I have to drill another hole for the cable to pass throught. 
On the concept of running 2 cables togehter to achieve better signal, does it work with speaker wire?
Currently, I am running 12 gauge speaker wire to the subwoofer. I think it is better if I run a 10 gauge to the subwoofer. Since I don't want to buy a 10 gague speaker wire and I have plenty of 14 gauge speaker wire, can I run 2 14gauge speaker wire to achieve the same level as a single 10gauge?



60ndown said:


> run another 8 guage...or 2 more.


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## Chaos (Oct 27, 2005)

Don't forget that the fuse near the battery must not be higher than the power rating of the wire regardless of what the amp is fused at.


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## jdzumwalt (Jul 13, 2009)

duckymcse said:


> Hmm...I am really thinking of trying with the 8 gauge first and see how it handle the JL HD750. I think it might handle fine, but the question is there any sound quality different when using 4 gauge vs 8 gauge?



Yeah I hope you wire doesn't melt then you have a nice little fire.
grab ahold of the wire check and see how hot it gets if it's warm to the touch you need much larger


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## psud3ity (Mar 10, 2009)

By all means. Definatley made a huge difference for me. I did 2 gauge for everything after I tried it on my amp's ground alone. I went the cheap route and went to advanced auto, if you ask for battery cable, they have it by the foot in the back. It's not pretty or anything but it's $1.88/ft. 1/4" techflex is a little tight but 3/8" probably fits perfectly over it.


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## danssoslow (Nov 28, 2006)

psud3ity said:


> I went the cheap route and went to advanced auto, if you ask for battery cable...


Is that wire in the pic bare?


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## Oliver (Jun 25, 2007)

Yes , it appears to be a grounding wire [ he is going to cover it with flex if I understand him


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## jstutzman (Aug 11, 2009)

I have read somewhere a long time ago that a .5V drop across the power wire is considered acceptable and very safe. I tried to find it to post a link but i thought it come from that BCAE website. If this is correct which im sure someone shortly will confirm or deny, you could calculate the current it would take to drop .5v, and fuse the wire at that current. Standard copper wire has a R of .0006401/ft so at 10 ft you are allowed to draw 78 A to maintain a max of .5V drop. So if your car is runnig at 14V that is about 1092W that is save for that wire. Now account for the Eff % which is probably 60% ish so you an OPP of 655W. If you know better specs such as the actual Eff or exactly the R of your wire you can redue the math but the method will still hold true.


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## E60M5Straw (Aug 9, 2009)

Hello,
I'm new to this forum. Do you think there is anything wrong with using my RCA interconnects and 8 ga power wiring from an old install (12 years ago). What about the speakers, amplifiers, and cross overs.

JDS


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## psud3ity (Mar 10, 2009)

danssoslow said:


> Is that wire in the pic bare?


It's coated in plastic, it's not completley bare.

I just am going the techflex route to kind of make it prettier.


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## danssoslow (Nov 28, 2006)

OK. 
I wasn't concerned so much with how it looked, but rather how it would hold up to oxidation and tarnishing. Leave that green copper stuff to old architecture.


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## beafer (Dec 14, 2008)

4 gauge, definitely. if the wire doesn't burn, that fuse block will. I made that mistake of running 4gauge to a block and 8 gauge out. everything under 7ft total and my block was melting its ass off. 8 gauge wire burned the hell up. I'm now 0 gauge in to 4 gauge out of the block and hoping for the best with this setup. Those HD750s demand plenty power and they can take 4 gauge input. I wish they could they can 0 gauge LOL.


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## t3sn4f2 (Jan 3, 2007)

beafer said:


> 4 gauge, definitely. if the wire doesn't burn, that fuse block will. I made that mistake of running 4gauge to a block and 8 gauge out. everything under 7ft total and my block was melting its ass off. 8 gauge wire burned the hell up. I'm now 0 gauge in to 4 gauge out of the block and hoping for the best with this setup. Those HD750s demand plenty power and they can take 4 gauge input. I wish they could they can 0 gauge LOL.


A distribution block can handle way more then the cable that goes in or out of it. It _your_ block is melting, it is due to inproper cable connection not improper wire gauge. The simple fact that the heat is at the area that can carry the most current and not at the cable somewhere points to that.


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## beafer (Dec 14, 2008)

t3sn4f2 said:


> A distribution block can handle way more then the cable that goes in or out of it. It _your_ block is melting, it is due to inproper cable connection not improper wire gauge. The simple fact that the heat is at the area that can carry the most current and not at the cable somewhere points to that.


It was melting where the 8 gauge for the 750 came out of the block. No place else. And the wiring wasnt faulty. It was snug. Just not big enough (wire).


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## t3sn4f2 (Jan 3, 2007)

beafer said:


> It was melting where the 8 gauge for the 750 came out of the block. No place else. And the wiring wasnt faulty. It was snug. Just not big enough (wire).


So you had 7 feet total and even less if you only count the 8 gauge by itself?


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## beafer (Dec 14, 2008)

No. it was 5ft of 4 gauge and like 1.5-2ft of 8 gauge wire to the amp.


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## t3sn4f2 (Jan 3, 2007)

beafer said:


> No. it was 5ft of 4 gauge and like 1.5-2ft of 8 gauge wire to the amp.


2 feet of 8 gauge copper wire can carry *389* amps (not watts) before it drops voltage by .5 volts. A lot more in order to get it to increase in temperature even.

Look for the problem elsewhere, physics does not lie.


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## beafer (Dec 14, 2008)

well...just upgraded the wire and i'm gonna keep monitoring it. will eventually change the block though cause it be just cheaply made.


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## Oliver (Jun 25, 2007)

a$$hole said:


> From basic car audio and electronics>
> 
> .................................class AB....class D
> 
> 8 awg....	*52* amps....	430 watts....	537 watts





t3sn4f2 said:


> 2 feet of 8 gauge copper wire can carry *389* amps (not watts) before it drops voltage by .5 volts. A lot more in order to get it to increase in temperature even.
> 
> Look for the problem elsewhere, physics does not lie.


Just be sure that it has no insulation on it [ might get a lil stinky ]

I think if you cut it down 6 more inches it will handle a quadzillion amps and you could wire The Hadron super collider with it , instead of those sections they are using


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## t3sn4f2 (Jan 3, 2007)

a$$hole said:


> Just be sure that it has no insulation on it [ might get a lil stinky ]
> 
> I think if you cut it down 6 more inches it will handle a quadzillion amps and you could wire The Hadron super collider with it , instead of those sections they are using


You're slipping.......

Go further down in the page and run the numbers for *2* feet instead of the general length noted on the chart you listed. 

Don't be surprised is the capacity is even higher, I made my calculations at the worst possible conditions of 50% eff. and 11 volts.


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## benny (Apr 7, 2008)

ahem. circular mils.

that is all.


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## The Duke (Nov 25, 2009)

OK, With the JL Audio amps you need current flow to make them perform properly. What this means to you is that you need a quality 4-gauge with a high strand count. I mention 4-gauge b/c the HD750/1 had a 4 gauge input on the amp. They would not offer a 4-gauge input if it did not need it. Also what type of vehicle is this being installed in??? Have you checked to see what your charging cable is off of you alt, if your charging wire is a 6-8 gauge and you are running a 4 gauge into the amp you are still choking the current flow to your amp and you should upgraded the charging lead off your alt and your ground on your factory batt. The other concern the type of wire that you are using. There are 3 major power wire types that you can buy in a store. The best power wire is Silver(most conductive) follower buy Copper (97.6% conductive as silver) and Copper Clad Aluminum or CCA (63% conductive as silver). CCA is the wire that you find in the $49.99 4-gauge amp kits as it is a cheap wire. Since you are using a amp that is 75% efficient @ full current flow with Silver wire, if you are using CCA wire that has 37% more resistance you amp will never be 75% efficient and you will likely have heating problems at connections and eventually electronic failure. Hope this helps!!!


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## benny (Apr 7, 2008)

The Duke said:


> OK, With the JL Audio amps you need current flow to make them perform properly. What this means to you is that you need a quality 4-gauge with a high strand count. I mention 4-gauge b/c the HD750/1 had a 4 gauge input on the amp. They would not offer a 4-gauge input if it did not need it. Also what type of vehicle is this being installed in??? Have you checked to see what your charging cable is off of you alt, if your charging wire is a 6-8 gauge and you are running a 4 gauge into the amp you are still choking the current flow to your amp and you should upgraded the charging lead off your alt and your ground on your factory batt. The other concern the type of wire that you are using. There are 3 major power wire types that you can buy in a store. The best power wire is Silver(most conductive) follower buy Copper (97.6% conductive as silver) and Copper Clad Aluminum or CCA (63% conductive as silver). CCA is the wire that you find in the $49.99 4-gauge amp kits as it is a cheap wire. Since you are using a amp that is 75% efficient @ full current flow with Silver wire, if you are using CCA wire that has 37% more resistance you amp will never be 75% efficient and you will likely have heating problems at connections and eventually electronic failure. Hope this helps!!!



I call ******** on solid silver power cable, and why the hell would you need high strand count cable for DIRECT CURRENT? For flexibility only. Also, upgrading the charge lead size isnt going to make his alternator magically make more amperage. 

MECP teach you that stuff?


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## t3sn4f2 (Jan 3, 2007)

The Duke said:


> OK, With the JL Audio amps you need current flow to make them perform properly. What this means to you is that you need a quality 4-gauge with a high strand count. I mention 4-gauge b/c the HD750/1 had a 4 gauge input on the amp. They would not offer a 4-gauge input if it did not need it. Also what type of vehicle is this being installed in??? Have you checked to see what your charging cable is off of you alt, if your charging wire is a 6-8 gauge and you are running a 4 gauge into the amp you are still choking the current flow to your amp and you should upgraded the charging lead off your alt and your ground on your factory batt. The other concern the type of wire that you are using. There are 3 major power wire types that you can buy in a store. The best power wire is Silver(most conductive) follower buy Copper (97.6% conductive as silver) and Copper Clad Aluminum or CCA (63% conductive as silver). CCA is the wire that you find in the $49.99 4-gauge amp kits as it is a cheap wire. Since you are using a amp that is 75% efficient @ full current flow with Silver wire, if you are using CCA wire that has 37% more resistance you amp will never be 75% efficient and you will likely have heating problems at connections and eventually electronic failure. Hope this helps!!!


Length of wire dictates current carrying capacity more then gauge. If you battery is near the amp or if a heavy gauge fed ditro block is, you don't NEED a 4 gauge to the amp. They put a 4 gauge on the plug because they have to accomedate a basic install where there is no distro block and the bat is far away. Which would be a case to use the 4 gauge.

You don't need to upgrade an alternator cable that is rated to handle the maximum current that the alternator can EVER put out.


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## benny (Apr 7, 2008)

length IS a factor, BUT you need sufficient cross-section in circular mils to carry the current, or it will heat up.


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## t3sn4f2 (Jan 3, 2007)

benny said:


> length IS a factor, BUT you need sufficient cross-section in circular mils to carry the current, or it will heat up.


I know, but length is a bigger factor in the equation. In other words, you should concider the length of the cable before you concider the gauge you are going to use, it plays a bigger roll.


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## Oliver (Jun 25, 2007)

Fill a 5 gallon bucket with water, now cut your hose as short as you want to and try it again.

Did it handle more flow, does the bucket fill faster ?


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## t3sn4f2 (Jan 3, 2007)

a$$hole said:


> Fill a 5 gallon bucket with water, now cut your hose as short as you want to and try it again.
> 
> Did it handle more flow, does the bucket fill faster ?


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## The Duke (Nov 25, 2009)

I never said it would make your alt produce more power. Thicker cable with higher thread count will allow the current that your alt produces to flow quicker. The thinner the wire the slower the current flow. And you wire type does make a difference. If you use a 4-gauge CCA wire over a run of 20ft you would have to use (2) CCA 4 gauge runs to allow the same current flow as a single run of copper/silver 4 gauge. This forum was designed to help with questions or problem, but since you are trying to be jerks. Thanks for playing and Yes M.E.C.P did teach me that and it should have taught you too.


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## benny (Apr 7, 2008)

so, it affects current _speed?_ Now that is a gem.


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## t3sn4f2 (Jan 3, 2007)

The Duke said:


> I never said it would make your alt produce more power. *Thicker cable with higher thread count will allow the current that your alt produces to flow quicker. The thinner the wire the slower the current flow.* And you wire type does make a difference. If you use a 4-gauge CCA wire over a run of 20ft you would have to use (2) CCA 4 gauge runs to allow the same current flow as a single run of copper/silver 4 gauge. This forum was designed to help with questions or problem, but since you are trying to be jerks. Thanks for playing *and Yes M.E.C.P did teach me that *and it should have taught you too.


They taught you that?!


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## jooonnn (Jul 26, 2009)

The JL Amps are VERY ineffecient imho. Close to a class AB, solely due to the power regulation technology. They compensate lower voltage with much more current to maintain steady power (watts). They sound great though, but JL designed these for SQ and performance not efficiency.


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## t3sn4f2 (Jan 3, 2007)

jooonnn said:


> The JL Amps are VERY ineffecient imho. Close to a class AB, solely due to the power regulation technology. They compensate lower voltage with much more current to maintain steady power (watts). They sound great though, but JL designed these for SQ and performance not efficiency.


So they aren't more efficient then a simularly regulated AB or D class amp at the same voltages?


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## danssoslow (Nov 28, 2006)

I don't trust those amperage calculators for ****. For a given size conductor, there will be a voltage drop as the length of the wire gets greater. Where those calculators get a bit silly is in the fact that there is a voltage RISE (beyond the conductors maximum ampacity) when the length gets shorter. This simply isn't true. If the csa of a given size isn't great enough to dissipate the heat, it doesn't matter how short it is, it's going to burn up.


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## t3sn4f2 (Jan 3, 2007)

danssoslow said:


> I don't trust those amperage calculators for ****. For a given size conductor, there will be a voltage drop as the length of the wire gets greater. *Where those calculators get a bit silly is in the fact that there is a voltage RISE (beyond the conductors maximum ampacity) when the length gets shorter.* This simply isn't true. If the csa of a given size isn't great enough to dissipate the heat, it doesn't matter how short it is, it's going to burn up.


Huh? So how come fuses don't burn up. They are way thinner then the cable. If the fuse element was 15 feet long it wouldn't burn up either? Might as well make a cable out of that fuse material and save some space and money then.


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## bamelanc (Sep 13, 2009)

The 750/1 requires a 60 amp fuse..regardless of how power hungry anyone thinks it is. 8 Gauge wire on a less-than-10 foot run should be sufficient if that's the only amp you have on that power run. 

I personally have 4 gauge wire ran, but I also have a 600/4 (and 750/1). It requires a 50 amp fuse. 110 amps total...well within the amp carrying capacity of a 4 gauge power wire in the confines of an automobile.

That being said, it's usually a good idea to have more than what you need...'specially for future upgrades and such. 4 gauge isn't that much more costly than 8 gauge.


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## danssoslow (Nov 28, 2006)

t3sn4f2 said:


> Huh? So how come fuses don't burn up. They are way thinner then the cable. If the fuse element was 15 feet long it wouldn't burn up either? Might as well make a cable out of that fuse material and save some space and money then.


Fuses aren't wire by any means. In high voltage disconnects, there are 600 amp fuses the same size as 250 amp fuses. Can't replace one with the other, even though the size is the same. We can't compare the two, due to the fact that fuses are made of different materials. What those materials are, I haven't the slightest idea; but when sizing wire for a particular amperage, length isn't a determining factor unless length and ambient temperature, pipe fill, etc. dictates that the size has to be bumped up, never down.


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## t3sn4f2 (Jan 3, 2007)

danssoslow said:


> Fuses aren't wire by any means. In high voltage disconnects, there are 600 amp fuses the same size as 250 amp fuses. Can't replace one with the other, even though the size is the same. We can't compare the two, due to the fact that fuses are made of different materials. What those materials are, I haven't the slightest idea; but when sizing wire for a particular amperage, *length isn't a determining factor **unless length *and ambient temperature, pipe fill, etc. dictates that the size has to be bumped up, never down.


 That seems like a contradiction.

I just looked online for 5 minutes and every professional site I saw contradicts what you are saying about length not being a determining factor. Here's just one that goes along with what Bcae1 claims. 

http://www.powerstream.com/Wire_Size.htm

Do you have somewhere that explains what you are saying.


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## bamelanc (Sep 13, 2009)

I think I may understand. Wire of a certain diameter can only carry so many amps. In the case of 4 gauge it's somewhere around 135 or so...regardless of length. So, given a set diameter (4g) and set voltage (13.8), the longer the wire a voltage drop will be experienced hence reduced wattage. If the voltage drops (12) and wire diameter is fixed, the more current it takes to maintain the same wattage on the other end specially in the case of amps with regulated power supplies. Did I get it right?


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## t3sn4f2 (Jan 3, 2007)

bamelanc said:


> I think I may understand. Wire of a certain diameter can only carry so many amps. In the case of 4 gauge it's somewhere around 135 or so...regardless of length. So, given a set diameter (4g) and set voltage (13.8), the longer the wire a voltage drop will be experienced hence reduced wattage. If the voltage drops (12) and wire diameter is fixed, the more current it takes to maintain the same wattage on the other end specially in the case of amps with regulated power supplies. Did I get it right?


Yeah you got what he said correct.


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## danssoslow (Nov 28, 2006)

danssoslow said:


> unless length and ambient temperature, pipe fill, etc. dictates that the size has to be *bumped up, never down*.


This is the important part when considering length. Always bigger, never smaller. 

The bold part you pointed out was ill written by me; and meant to say a *shorter* length isn't a determining factor to _increase_ the amperage a wire is able to safely support.

This is part of table 310.16 of the NEC. The table lists ampacities of different sized conductors devided into insulation types and temperature ranges.










Notice that lengths are not involved in this table. These are maximum ampacities, regardless of any other factors; and _most_ other factors, such as length, will only serve to increase the load on a wire, not decrease.


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## The Duke (Nov 25, 2009)

Wow, I am noticing some "installers" that are really full of them self and their opinions. So here it goes. These are ref material for you to chew on from the Iasca handbook and also from a audio testing lab via CarAudioMag.com. I do not have a big ego, I am not trying to win a pissing match but i would be willing to bet that the people who made these ref guides and ran these test's are smarter than me and most of you. If you follow these guidelines you should not have any problems and you should also have a lot less electronics failures due to abuse. It has worked for me for years and it should work for you. 


Wire Gauge Resistance per foot

4 .000292
6 .000465
8 .000739
10 .00118
12 .00187
14 .00297
16 .00473
18 .00751
20 .0119
22 .0190
24 .0302
26 .0480
28 .0764


Length of run (in feet)
Current 0-4 4-7 7-10 10-13 13-16 16-19 19-22 22-28

0-20A 14 12 12 10 10 8 8 8
20-35A 12 10 8 8 6 6 6 4
35-50A 10 8 8 6 6 4 4 4
50-65A 8 8 6 4 4 4 4 2
65-85A 6 6 4 4 2 2 2 0
85-105A 6 6 4 2 2 2 2 0
105-125A 4 4 4 2 2 0 0 0
125-150A 2 2 2 2 0 0 0 00

Copper Wire Vs. Copper Clad Aluminum Wire - Wire Warnings
Not All Cable Is Created Equal
By Garry Springgay, Cogent Audio Labs (Via CarAudioMag.com)

Copper Wire Vs. Copper Clad Aluminum Wire - Wire Warnings

The best metal for conducting electricity isn't gold, as many believe. The absolute best conductor is pure silver. The second best is copper, with a very good conductivity at 97.6 percent that of silver. This is the main reason that copper has been the most popular material for an electrical conductor-it's a fraction of the cost of silver, with almost equalperformance. Gold comes in third, with 76.6 percent the performance rating of silver (the real benefit to gold is its ability to resist corrosion and oxidization). Aluminum, however, comes in a distant fourth at the 63 percent mark, or about two-thirds the conductivity of copper. Stated another way, and when we include the tiny bit of copper applied, CCA cable has about 34 percent greater resistance than a pure copper cable of the same gauge and construction. Let's take a look at what that additional resistance can mean in the real world of car audio.



P.S. the guy who made the quote about the draining a 5 gallon bucket with a garden hos comment. If you have 2 garden hoses the same outside dia. and one has a 1/4" hole and one has a 1/2" hole, you are saying the larger hole WONT drain the bucket quicker???? What physics dont apply place do you live in???? I want to move there!!!


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## t3sn4f2 (Jan 3, 2007)

danssoslow said:


> This is the important part when considering length. Always bigger, never smaller.
> 
> The bold part you pointed out was ill written by me; and meant to say a *shorter* length isn't a determining factor to _increase_ the amperage a wire is able to safely support.
> 
> ...



I see what you are saying but that chart is for home wiring where there is not going to be a 2 foot run.

It leads me back to the same thing kinda of. A 300 amp fuse is not made out of a superconductive material. Yet it can pass that current all day.

If we go by that home chart and don't concider length then you could not connect an amp like an ARC SE4200 because it has 120amps of fusing, consumes 185 amps max at 1 ohm and only has a 4 gauge set screw port. What gives there? You need a 0 gauge with a reducer? Even that won't do.

Why does it work because they take a maximum length ty[ical in a car run when they put that 4 gauge set screw port.

Or so it looks like to me.


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## t3sn4f2 (Jan 3, 2007)

The Duke said:


> Wow, I am noticing some "installers" that are really full of them self and their opinions. So here it goes. These are ref material for you to chew on from the Iasca handbook and also from a audio testing lab via CarAudioMag.com. I do not have a big ego, I am not trying to win a pissing match but i would be willing to bet that the people who made these ref guides and ran these test's are smarter than me and most of you. If you follow these guidelines you should not have any problems and you should also have a lot less electronics failures due to abuse. It has worked for me for years and it should work for you.
> 
> 
> Wire Gauge Resistance per foot
> ...


I like that chart, it shows why you are wrong in upgrading the alternator cable. Thanks for diggin it up.


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## The Duke (Nov 25, 2009)

Np. The main purpose for upgrading the charging lead in a vehicle is to cover all of your bases. If you have a 6 gauge charging lead going to your main battery under the hood and you want to run a 4-gauge wire to your amps you will only get the amount of current flow that a 6-gauge wire can allow even though you have a 4 gauge wire ran. The battery cannot create amperage. If you do a 4 gauge install you should also do a 4 gauge charging upgrade as well.


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## SoundChaser (Apr 3, 2009)

Wire capacity should actually be calculated in watts not amps. There is a big difference between 14volts and 120volts. If you’re working on your car stick with the car audio charts. If you plan on wiring your house, please use approved home wiring charts.


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## danssoslow (Nov 28, 2006)

Keep in mind that chart applies to all form of high voltage; including industrial, where there are plenty of runs within a foot of its disconnecting means.

Onto an automotive situation, this is a high voltage chart, and doesn't account for low voltage applications; although I do believe it is a safe standard by which to choose a proper sized conductor. I do admit I am by no means educated on the requirements in automotive apps; so I rely on this chart due to the fact it is based on applied amperage requirements.

If I had to take a stab at understanding why it is possible to run some of these amps with what appears to be an undersized conductor; it would be due to the wire requirements being based on (1) an averaged power consumption and (2) that most amplifiers have their own overcurrent protection.

Notice in my last post, in the last sentence I said _*most*_ other factors? Not as an out; but there are a couple situations, which I figured we might not get into, that the conductors feeding a circuit can appear to be grossly undersized, yet it's perfectly safe. The one common area that this happens is in air conditioning systems. 
The conductors are sized according to the Minimum circuit ampacity as displayed on the AC unit's name plate. The breaker is sized according to the Maximum circuit ampacity displayed on the name plate. Thus, it isn't uncommon to run a #14-12 conductor to an AC unit that is fused at 30-40 amps. Bear with me, as this coincides with why I figure car amps get away with this.
The inrush current of the motor on the AC unit dictates the breaker size, not unlike an amp's fuse recommendations will be based on its peak amp draw during a dynamic portion in the music. Its protection must be able to sustain the regular peaks that are involved it its normal usage.

An AC unit's wire requirements are based on its normal operating range. This is where its running amperage is, and the heat involved at that ampacity. The spike in amperage incurred when the motor starts up isn't high enough nor sustained long enough to cause a problem to the conductors feeding the AC unit. Conversely, the time an amp spends at maximum wattage is also very short; and its wire requirements are also considered safe to conduct such loads for short periods.

The last step in insuring that this system works in AC units is the internal safety measures contained within the AC unit. These safety measures insure that if there is an internal problem (motor continues to try to start up, but never levels off, etc.) where the amperage stays constantly above the average power consumption, but less than the overcurrent protection feeding the unit (the breaker won't trip), that the unit itself will shut down, protecting the feeders. Most amplifiers also have this protection, in the form of internal breakers, protection circuits, etc.

This is my guess as to why the ARC, and amps like it, have such small requirements. You will have to back me up on this one, as I don't own any or have noticed, but most amps that cater to huge sub systems (or even class D, sub-only amplifiers) have bigger lugs with similar power to the ARC, correct? Knowing the people they cater to will require higher average consumption due to the sustained bass notes/test tones.


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## danssoslow (Nov 28, 2006)

SoundChaser said:


> Wire capacity should actually be calculated in watts not amps.


This simply isn't true. It's purely based on ampacity. Ever see the conductor inside of a power line? It carries well over 600 volts, and is about the size of a #14 wire.

A 20 amp circuit in an industrial 277v circuit will use the same #12 wire that is used in a residential 120v 20a circuit, yet there is a 3140 watt difference.


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## danssoslow (Nov 28, 2006)

The Duke said:


> Wow, I am noticing some "installers" that are really full of them self and their opinions.


One of the great things about this site is that everyone, regardless of background, is free to input on whatever subject without fear of being called out because most check there egos at the door. Nobody here is being full of themselves, nor calling themselves "installers". Comments like this aren't necessary.


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## SoundChaser (Apr 3, 2009)

danssoslow said:


> This simply isn't true. It's purely based on ampacity. Ever see the conductor inside of a power line? It carries well over 600 volts, and is about the size of a #14 wire.
> 
> A 20 amp circuit in an industrial 277v circuit will use the same #12 wire that is used in a residential 120v 20a circuit, yet there is a 3140 watt difference.


Overhead? 
Isn’t the goal to calculate how much heat (aka, power) a wire can dissipate safely?


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## danssoslow (Nov 28, 2006)

SoundChaser said:


> Isn’t the goal to calculate how much heat (aka, power) a wire can dissipate safely?


Yes; and that heat is based solely on amperage, not voltage. Mind you, there is a maximum voltage a wire can conduct; but it is high enough to not be related. The wire in household Romex is safe to 600v; but chances are slim to none that it will ever see anything remotely close to that. Some low voltage control wire is also rated to 600v; but it won't have any bearing on its current carrying abilities.


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## t3sn4f2 (Jan 3, 2007)

The Duke said:


> Np. The main purpose for upgrading the charging lead in a vehicle is to cover all of your bases. If you have a 6 gauge charging lead going to your main battery under the hood and you want to run a 4-gauge wire to your amps you will only get the amount of current flow that a 6-gauge wire can allow even though you have a 4 gauge wire ran. The battery cannot create amperage. If you do a 4 gauge install you should also do a 4 gauge charging upgrade as well.


You're not gettin it.


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## t3sn4f2 (Jan 3, 2007)

danssoslow said:


> Keep in mind that chart applies to all form of high voltage; including industrial, where there are plenty of runs within a foot of its disconnecting means.
> 
> Onto an automotive situation, this is a high voltage chart, and doesn't account for low voltage applications; although I do believe it is a safe standard by which to choose a proper sized conductor. I do admit I am by no means educated on the requirements in automotive apps; so I rely on this chart due to the fact it is based on applied amperage requirements.
> 
> ...


Hhmm, not always. This amp is about as sub only as you can get. 300 amp pull with 0 gauge in.

Sundown Audio - SAZ-3500D

An Arc SE4000 has dual 0 guage inputs, but that one is not class D and pulls 450 amp at low distortion watts at half what the amp can put out.

http://http://www.arcaudio.com/productdescription_pages/amplifiers/signature-edition/se4000.asp


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## t3sn4f2 (Jan 3, 2007)

Another point on the fusing debate.










No special fuse element and it has a fuse like botteneck.


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## danssoslow (Nov 28, 2006)

t3sn4f2 said:


> Hhmm, not always. This amp is about as sub only as you can get. 300 amp pull with 0 gauge in.
> 
> Sundown Audio - SAZ-3500D
> 
> ...


Mentioning class D was more of a reach at grouping amplifiers for subbass duties; trying to supports my assumptions above. Either way, it doesn't seem to support my "theory".

Other than some half-assed attempted guesses blush, I don't know how they come about deciding the amps wire requirements. I am however interested in knowing the answer. That, and how guage/amp requirements are configured. One of the audio industry guys here needs to fetch some hard answers on these.


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## SoundChaser (Apr 3, 2009)

danssoslow said:


> Yes; and that heat is based solely on amperage, not voltage. Mind you, there is a maximum voltage a wire can conduct; but it is high enough to not be related. The wire in household Romex is safe to 600v; but chances are slim to none that it will ever see anything remotely close to that. Some low voltage control wire is also rated to 600v; but it won't have any bearing on its current carrying abilities.


If it’s based solely on amperage, not voltage, how come the wiring charts for 12v car audio are vastly different than charts for 115v home wiring?

I guess if you stick with manufactures recommendations and building codes you should be alright.


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## IBcivic (Jan 6, 2009)

8ga makes good subwoofer wire

i got it for free and it was purdy[blue] ...i figured i'd use it for something. 


imho running a 0ga is just being smart ...as anyone knows in this hobby...you just never stop upgrading.having to re-do the power run , to me , would be a pain in the ass


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## kapone (Sep 22, 2009)

stinky06 said:


> 8ga makes good subwoofer wire
> 
> i got it for free and it was purdy[blue] ...i figured i'd use it for something.
> 
> ...


lol...You're probably right, and I guess I'm lucky in owning a BMW. The battery is on the right side of the trunk, and the car's electronics, including the factory radio and amp are on the left. The "power" wire run, is something like 2ft, if your amps sit in the trunk somewhere.


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## danssoslow (Nov 28, 2006)

SoundChaser said:


> If it’s based solely on amperage, not voltage, how come the wiring charts for 12v car audio are vastly different than charts for 115v home wiring?


I have absolutely no idea. Sticking with manufacturers' recommendations are safe; but when using multiple amps, and feeding the distribution blocks, who came about these requirements and what are they based on? 

TheDuke is correct. The IASCA should be well versed on this. It couldn't be a bad thing to follow; but these ultra high voltages through such small wire seems spooky. Better much safe than sorry.


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## cmayo117 (Aug 14, 2009)

The Duke said:


> Np. The main purpose for upgrading the charging lead in a vehicle is to cover all of your bases. If you have a 6 gauge charging lead going to your main battery under the hood and you want to run a 4-gauge wire to your amps you will only get the amount of current flow that a 6-gauge wire can allow even though you have a 4 gauge wire ran. The battery cannot create amperage. If you do a 4 gauge install you should also do a 4 gauge charging upgrade as well.


The battery can't create amperage? Really? Then whats supposed to start your car? Car batteries can produce a huge amount of current for a short amount of time.

I do agree that it is good practice to upgrade your big 3 to at least the same size wire as you run to your amps.


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## IBcivic (Jan 6, 2009)

cmayo117 said:


> Then whats supposed to start your car? Car batteries can SUPPLY a huge amount of current for a short amount of time.


^^^FIXED^^^


Car batteries are storage devices...not generating devices.


if your alternator produces 70amps[my civic for example].... it is a complete waste of time and money , up-grading to 0ga[my power run to my trunk]

but when i put in the 220 amp alt [sitting in my bed-room]in .....it won't be


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## cmayo117 (Aug 14, 2009)

stinky06 said:


> ^^^FIXED^^^
> 
> 
> Car batteries are storage devices...not generating devices.
> ...


That is true, but they can respond to large current demands much faster than an alternator. That's what i was trying to say. 


I drive a civic also, and i do not think it is a COMPLETE waste to upgrade the big 3 for such a small alternator. Even if the factory wiring is big enough to keep up, heavier gauge wire will always be at least a little more efficient.


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## t3sn4f2 (Jan 3, 2007)

danssoslow said:


> *I have absolutely no idea. Sticking with manufacturers' recommendations are safe; but when using multiple amps, and feeding the distribution blocks, who came about these requirements and what are they based on? *
> TheDuke is correct. The IASCA should be well versed on this. It couldn't be a bad thing to follow; but these ultra high voltages through such small wire seems spooky. Better much safe than sorry.


I'm sure it's based simply on math using physics formulas and the resistive properties per foot of the given material. BCAE1 seems to explain it fairly detailed.


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## Oliver (Jun 25, 2007)

SoundChaser said:


> If it’s based solely on amperage, not voltage, how come the wiring charts for 12v car audio are vastly different than charts for 115v home wiring?
> .


Ohm's Law will help you here 

If the pressure is lower the flow needs to be greater [ 120 volts = pressure and 12 volts equals pressure too ! ]

amperes = flow rate

size of conductor is going to be large enough to handle flow rate.

NPDang use 12 guage wire with high efficiency drivers and not pushing your amps into distortion area, this will work fine

*BCAE has numerous pictures and diagrams to explain this !*


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## danssoslow (Nov 28, 2006)

t3sn4f2 said:


> I'm sure it's based simply on math using physics formulas and the resistive properties per foot of the given material. BCAE1 seems to explain it fairly detailed.


One would think, yet the maximum ampacities of a given wire are way off between AC and DC applications. I realize that unbalanced loads in an AC circuit can create heat; maybe this isn't an issue with DC configurations?

I'll read up at BCAE1. Thanks for that!


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## Austin (Mar 12, 2009)

collinr said:


> uiop


Stop spamming up the forum dude.


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## The Duke (Nov 25, 2009)

Thanks for the support on this danssoslow. At this point this is kind of like beating a dead horse. And if you are into that kind of thing keep pounding away on your keyboard. This was supposed to be a way of helping duckymcse with his HD750/1 question and it spawned into a circle jerk debate. The HD750/1 uses a regulated power supply which means current flow is king. Their R.I.P.S technology allows the amp to function with full output from 11v-14.5v. This means that caps are bad as they limit current flow and keep voltage high and you want to use the largest wire that you can get into the amp to allow the most current flow. 

(From JL Audio HD750/1 owners manual)-Power Wire Requirements
The HD750/1’s “+12 VDC” and “Ground”
connections are designed to accept 4 AWG power
wire. 4 AWG pure copper wire is recommended
for any power wire run longer than 72 inches (180
cm). For runs shorter than 72 inches, 8 AWG pure
copper power wire is acceptable.

We do not recommend the use of “copperclad
aluminum wire” or “CCA” wire because
this wire is significantly less conductive than
pure copper wire. Only use pure copper power
wire, such as JL Audio’s MetaWire™. Tinned
copper wire (silver color) is acceptable as the
tin-plating is only a very minor component of
the wire.

As it clearly states anything shorter than 72 inch's (6ft) and 8 gauge is no problem. As duckymcse stated he has about a 8ft run which would require a 4 gauge wire run. These are using pure copper wire not copper clad aluminum which as we learned earlier in this thread is not good to use if using CCA you should run a second wire to allow proper current flow.


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## t3sn4f2 (Jan 3, 2007)

The Duke said:


> Thanks for the support on this danssoslow. At this point this is kind of like beating a dead horse. And if you are into that kind of thing keep pounding away on your keyboard. This was supposed to be a way of helping duckymcse with his HD750/1 question and it spawned into a circle jerk debate. The HD750/1 uses a regulated power supply which means current flow is king. Their R.I.P.S technology allows the amp to function with full output from 11v-14.5v. This means that caps are bad as they limit current flow and keep voltage high and you want to use the largest wire that you can get into the amp to allow the most current flow.
> 
> (From JL Audio HD750/1 owners manual)-Power Wire Requirements
> The HD750/1’s “+12 VDC” and “Ground”
> ...


:laugh:

Just stop please, save yourself further embarrassment.


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## JJDH (Mar 8, 2009)

op never said what brand of 8 awg......might not be tru 8awg......upgrade to 4 at least


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## The Duke (Nov 25, 2009)

t3sn4f2 said:


> :laugh:
> 
> Just stop please, save yourself further embarrassment.


mighty high horse you got there


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## t3sn4f2 (Jan 3, 2007)

The Duke said:


> mighty high horse you got there


Relative to you? Mr. Ed on the tip of Mount Everest.


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## Oliver (Jun 25, 2007)

t3sn4f2 said:


> Another point on the fusing debate.
> 
> 
> 
> ...


What are the conductivity measurements ?

Is this made from copper ?

Are your fuses made of copper ?

How thick does silver solder need to be to insure optimal flow on a wire ?

Is a crimp connector a good connection alternative ?


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## Oliver (Jun 25, 2007)

The Duke said:


> These are using pure copper wire not copper clad aluminum which as we learned earlier in this thread is not good to use if using CCA you should run a second wire to allow proper current flow.


Just use the appropriate sized aluminum wire [ no need for a second wire ]

Check in tables [ generally a size larger for same amount of flow ]


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## bamelanc (Sep 13, 2009)

This is _still_ a debate? I hope someone answered the dude's question.


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## t3sn4f2 (Jan 3, 2007)

bamelanc said:


> This is _still_ a debate? I hope someone answered the dude's question.


Indirectly? Many times over probably :laugh:


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## jimbo2246 (Dec 1, 2009)

Replace it with some good 4 gauge (JL Audio Power wire?). You only need 8 feet, it shouldn't cost more than $20.00.


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