Repurposing Computer Power Supply Wiring

[minim]

When talking to a tech a number of years ago he shared how he used this wire. I quizzed him about it due to the conductors appearing to be plain steel, and he asserted that it's tinned copper. Following various stripping, scraping, scratching, shearing attempts I haven't seen a glimpse of any coppery shine to the conductors.

Would one be advised to not use wire, with no copper content, in an amp?

I'm one of these people who likes to reuse stuff or find new uses for stuff instead of binning it.

Most of the stuff I have here is around 16-22 AWG, rated at 300V, 80-90 deg C. Obviously dc voltages in most amps exceed 300V.

Anybody care to comment that'd be lovely.

[Helmholtz]

You can test for steel using a Neo magnet. And of course steel is much more sturdy and resilient than copper.

Apart from silver, copper is the best conductor available. Steel is a rather poor conductor, producing increased losses and possible ground loop problems in an amp.

[R.G.]

It would be very unusual for the wiring to be steel, but I guess it's possible. More likely it's tinned copper. As Helmholz notes, a magnet tells the tale.

Solder plated steel has been used for some component leads, notably for resistors, as I found in one of my own early magnet tests. There's no particular problem with using low-carbon steel as wiring, if you take into account:
> it rusts, so it has to be completely coated; this is one reason it's unlikely that what you saw was steel
> it is higher resistance than copper; this is no problem if you are aware of it and take the right design measures; all wires are low value resistors
> it has different structural properties than copper, including faster work hardening and cracking.

[tedmich]

wouldn't computer PS wire be expected to be aluminum? Its way cheaper than copper and conducts enough for the short runs present in the PS.
When $0.30 per unit is the difference between profit and loss the beancounters downgrade everything they can get their spreadsheet on.

[Enzo]

HAve you soldered much to aluminum lately?

[Helmholtz]

wouldn't computer PS wire be expected to be aluminum? Its way cheaper than copper and conducts enough for the short runs present in the PS.
When $0.30 per unit is the difference between profit and loss the beancounters downgrade everything they can get their spreadsheet on.

Al would pose a major soldering problem.

Sorry, crossposting.

[mozz]

All those Chinese LED Christmas light strings are steel, they rust. More garbage. I lucked out and got 2 full boxes of teflon wire of assorted gauges. You want a good supply, get one of those free organs in the newspaper or Craigslist.

[tedmich]

While its true silver colored cheap wire is usually steel, copper clad aluminum (CCA) is quite common, try finding a car amp installation kit or jumper cables that don't have these innocent 3 letter tucked somewhere in the fine print. All of HF's cheap jumper cables are this stuff I believe. The density is way off real copper but the silver core can be hard to see in the tiny gauges used in many rope type cables. A little dilute HCl will show the characteristic H2 evolution from the cut ends when Zn or Al are present (as in US pennies)

[g1]

While its true silver colored cheap wire is usually steel, copper clad aluminum (CCA) is quite common, try finding a car amp installation kit or jumper cables that don't have these innocent 3 letter tucked somewhere in the fine print. All of HF's cheap jumper cables are this stuff I believe. The density is way off real copper but the silver core can be hard to see in the tiny gauges used in many rope type cables. A little dilute HCl will show the characteristic H2 evolution from the cut ends when Zn or Al are present (as in US pennies)

Wasn't there a big deal about mixing copper and aluminum wiring in house electrical? How does CCA get around this?

[minim]

Wasn't there a big deal about mixing copper and aluminum wiring in house electrical? How does CCA get around this?

Having done a bit of reading, it seems it's not a problem if there's no electrolyte present. Some uses may require that the cable is sealed sufficiently from contaminants, or in the case of jumper cables, use is intermittent? Or perhaps the clamps are sealed well to the cable.

Either way, probably not a good idea in long-term fixed applications such as house wiring and I'm buggered if I want it in my house.

My computer cables here aren't attracted to a magnet at all. I don't think there's copper in it. More likely nickel or zinc or somesuch. I'll play it safe and scrap it.

[dmeek]

As I remember it the problem with aluminum wire is that it is too soft, will squash under a screw and loosen easily, then arc over and burn your house down, whereas copper has a bit of springyness which helps keep it tight.

[bsco]

As I remember it the problem with aluminum wire is that it is too soft, will squash under a screw and loosen easily, then arc over and burn your house down, whereas copper has a bit of springyness which helps keep it tight.

A friend of mine had bought a house years ago......when he had everything approved and had moved in, he discovered that the electrical wiring was aluminum....and it all had to be ripped out and completely re-wired....Aluminum was used for awhile in house wiring but it was discovered that it generated too much heat in the wiring and houses would catch fire.....so it was banned......

[olddawg]

Your ubiquitous “clear” wire speaker has stranded copper and stranded (stainless) steel wire...

[bsco]

Your ubiquitous “clear” wire speaker has stranded copper and stranded (stainless) steel wire...

I did not know that...and I really never put much thought into the composition of various types of wire to be quite honest........
Cheers

[Enzo]

That would surprise me. I'd be quicker to believe the clear speaker zip cord was copper and tinned copper. Why bother with a whole different wire than copper JUST for color contrast? You can also note many if not most zip cord, clear or not, differentiates by feel. One side is smooth, the other side ribbed.