The least resistance in power wire?

[oxphatxo]

I keep hearing people saying that using wire from welding machines is the WRONG stuff to use as it has high resistance. Then I hear other people say nothing about resistance, and lots about how much more pure it is and durable and especially cheaper it is then regular car audio power wire.
While i'm on this topic, does anybody know what to look for in proper low resistance high quality power/ground cable? ie: copper, or copper mixed with other metals, size of rubber coating or if the thickness of rubber coating even matters that much.
Please elaborate on this matter if you know what we may not know and feel free to leave your favorite brands of wire here.
Thanks.

[Francious70]

You want power wire that is 99.9% pure copper which all "power wire" and just about every "welding cable" I've ever seen. You want to look for what has the most strands for the size wire you're looking at for flexibility. Example:

Wire A is 4 gauge and has 2,000 strands
Wire B is 4 gauge and has 3,000 strands

Wire B is going to be more flexible.

And as far as insulation thickness, as long as it completely covers the wire you should be good.

[oxphatxo]

Thanks for the reply, I have been doing some reading on bcae1.com/wire.htm and in this section I found a quote that I found interesting. Take a read and lets see what others have to say about copper with tinned coating. Maybe someone can discuss what is wrong with a tinned coating?

URL: http://www.bcae1.com/wire.htm (under the oxygen free copper heading)

"As you have probably noticed, wire designated as OFC wire usually has a clear insulation and the wire is bright and shiny underneath the transparent insulator. Well... It is nice and shiny for a while but after a short time (actually from the time it is drawn), it starts to oxidize (unless the wire is kept in an oxygen free atmosphere). When copper oxidizes, it becomes a less effective conductor. This means that, in time, the wire's current carrying capabilities will become significantly reduced. The problem is made worse by having many very small conductors. This creates even more surface area which makes the oxidation process even more efficient. In my opinion, if you are designing a system of any type for long term use, I think the better choice is a 'tinned' copper wire. In this type of wire, the copper is plated with tin (maybe a lead/tin alloy) or similar conductor which will not oxidize as quickly and never as completely as the bare copper. As a side note, this has nothing to do with the copper being 'oxygen free'. It has everything to do with the fact that the wire is unprotected (untinned) and is finely stranded. I used OFC wire in this example because most OFC has many fine unprotected strands."

[Stereo Junkie]

Physics state that the electrons will move on the outside of the wire. So a thought of mine in previous years has been that the more strands the greater the surface area, but you must remember that all the strands are so tight that there really is no enough of a surface area increase to reduce the resistance in the line. I remeber seeing a test on that somewhere but can not find the link right now, basically it pitted MonsterCable with some hugh strand count and some basic welding wire with a really low strand count and both had the same resistance.

So the short of it is, Francious70 is absolutely right.

I have always run welding cable as both my power and ground. It has never been an issue and my systems have always sounded great.

The physics prove Francious70 right.

[Bfowler]

^ i was just going to add that.

well put.

[Jacampb2]

Physics state that the electrons will move on the outside of the wire. So a thought of mine in previous years has been that the more strands the greater the surface area...

The situation you are describing is called "skin effect" and it only happens at very high frequencies. It has absolutely no bearing whatsoever on the wire you use to supply power to your amps. Perfect DC has no frequency at all, although all rectified DC has some AC ripple still, it is negligible in this case. You can happily use solid copper buss to supply your system if your wallet permits it and you can insulate it.

High frequency high voltage power cables can be and often are hollow and in some cases, liquid cooled. Google skin effect to learn more.

As for different metals, and alloys, pure copper is the best, actually affordable electrical conductor.

Later,
Jason