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Power Wire Equivalent

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=50140
Printed Date: March 29, 2024 at 12:13 AM


Topic: Power Wire Equivalent

Posted By: evanc
Subject: Power Wire Equivalent
Date Posted: February 15, 2005 at 8:03 AM

Would running 2 strands of 4 awg power wire roughly 15 feet be the same as running 1 strand of 1/0 awg and distributing it to two strands of 4 awg in the back?

If not, what is 1/0 awg's equivalent in 4 awg strands?

Thanks

Evan




Replies:

Posted By: Francious70
Date Posted: February 15, 2005 at 9:07 AM
I'd say 1/0 gauge is the same as four 4 gauge.

Paul




Posted By: evanc
Date Posted: February 15, 2005 at 9:50 AM

Why am I having trouble finding distrobution blocks with 1 1/0 in and 4 4 awg outs...

I find 2 1/0 in and 4 4awg out.  Would I just not use 1 of the 1/0 inputs?





Posted By: oonikfraleyoo
Date Posted: February 15, 2005 at 10:15 AM
yup just use one of em and leave the other alone

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Posted By: DYohn
Date Posted: February 15, 2005 at 10:43 AM

0AWG cable contains 106000 circular mils of wire.  4AWG contains 41700 circular mils of wire.  That means it takes 2.5 (or 3, since you can't have the .5) 4AWG to contain the same amount of wire as one 0AWG.

Realize that it is not exactly the same thing to run multiple small cables as running one large cable because you introduce other effects (like higher net resistance per foot ince 4AWG is more than twice as resistant as 0AWG) and have more chances for bad connections, etc. but in general you achieve an equivalent current capacity by running cables in parallel.



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Posted By: newtone
Date Posted: February 15, 2005 at 8:15 PM

according to the 1951 Federal Electrician's Code Book

4awg=105amps

0awg=190amps

the little chart thingy i have here with that info doesnt state how long the wire can be to carry that amperage, but thats besides the point.  it is easy to see that 2 4awg carries more current than a single 0 awg.  hope this helps.



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Posted By: stevdart
Date Posted: February 15, 2005 at 8:33 PM

That's funny...1951.  Here's an electrician's chart that shows something different, yet.

...following the Handbook of Electronic Tables and Formulas for American Wire Gauge. As you might guess, the rated ampacities are just a rule of thumb. In careful engineering the insulation temperature limit, thickness, thermal conductivity, and air convection and temperature should all be taken into account. The Maximum Amps for Power Transmission uses the 700 circular mils per amp rule, which is very very conservative. The Maximum Amps for Chassis Wiring is also a conservative rating, but is meant for wiring in air, and not in a bundle. 

Truth is, we will find a very wide variety of recommendations of amperage ability with different gauge wires.  But wire is wire, and mass allows for less resistance, and if  one wire is the same quality of copper twisted wires and same quality of insulation rated thickness : gauge.....then the wire that is 2 1/2 times the mass of the smaller wire will allow more current transfer without excessive heat than the small wire will, by 2 1/2 times.



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Posted By: newtone
Date Posted: February 15, 2005 at 11:29 PM

hey, the 1951, its all i had availableposted_image  btw did you read the chart on your link?  it shows that chassis wiring

4awg=135

0awg=245

so thanks for proving my point for me.  granted, it also shows for power transmission (as in power line from electrical plants to your home)in which case the 0 awg flows greatly more current.  but since i dont think evanc is going to be running 200 miles  of wire to power his system the negligible difference in impedance isnt going to affect him or his current very much.  imo, he'll be fine with 2 4awgs, believe me, been there done that.  we always have better luck running multiple smaller cable than one larger and then distributing.  i think the distribution blocks may be responsible for alot of that  dreaded resistance. 

btw, in the first paragraph on your link. its double aught, as in zero, not 'nought.'  things like that make you wonder if the authors even have any experience with what theyre writing about.



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Posted By: stevdart
Date Posted: February 16, 2005 at 7:27 AM

so thanks for proving my point for me.  (newtone)

Not the case.  Read my post again.  (The reference I cited was just one of a few thousand entries in a Google search.  If the wording of it is not to your liking, do a search and pick something that uses better grammar.)

it is easy to see that 2 4awg carries more current than a single 0 awg.  (newtone)

That's the line you wrote that was I was referring to.  DYohn just proved prior to your post that 1/0 gauge is bigger than two 4 ga.



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: newtone
Date Posted: February 16, 2005 at 11:10 AM

i used a federal reference that electricians use. not some unsupported bs off of any site on the net.  thats the point i was making about authors not knowing what they are talking about.  your graph supported my opinion though. if you cant see that im sorry.   anyway im not going to get into a pissing contest with you over this, these are only our different opinions

evanc if you want to actually find out for yourself if the 2 4awg will flow the current you need, do a little hands on experiment.  fuse your 2 4 awg lines at the battery with twice the amperage draw you expect size fuse and attach the length wire you think youll need  then simply short them out.  if the fuses pop i guess the 4 awg will flow the current you need.   then you will know for yourself and be able to tell me or anyone else what you have actually seen with your own eyes, not read somewhere.  



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Posted By: DYohn
Date Posted: February 16, 2005 at 11:36 AM

I get my information from ANSI and the NEC.

The ampacity of wire is determined by several things, but the two main ones are total circular mils of copper (the size of the wire) and the type of insulating material (different classes of wire resulting in different temperature and max current specs.  Teflon is best, PVC is worse, etc.)  The limiting factor in ampacity is the ability to dissipate heat.

4 AWG wire, single condustor in air at 86 degrees F, is rated between 105 and 140 amps depending on the insulation class.  0 AWG wire is rated between 195 and 260 amps  Multiple conductors do not simply add up as there are other factors including resistance and heat between wires to consider.  When using multiple conductors you must de-rate by a factor of about the square root of 3.



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Posted By: MBZ oe
Date Posted: February 16, 2005 at 8:00 PM

Here is a link to a 1-0ga and 4-4ga dist block. It's what I had to use to hook up my US2000 Amp

https://www.darvex.com/miva/merchant.mvc?Screen=PROD&Product_Code=PB-1044&Product_Count=1



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