Copper core with aluminum clad ??

[Sam Morris]

Wiring in electrical panel in a 1950's home, copper core with aluminum clad. Is this type wire the same as solid aluminum (the bad stuff) ??

[Jerry Peck]

That isn't aluminum clad copper, that is "tinned copper".

The copper reacted with the rubber insulation, so the copper wiring was "tinned" to keep the copper separate from the rubber.

Tinned copper was a great conductor, the issue now (meaning 'nowadays') is that the rubber insulation has likely dried out and is hard, brittle, cracked, and not much good anymore.

I would recommend that an electrical contractor verify the condition of the rubber insulation to make sure the insulation is still good.

http://www.ecmweb.com/test-amp-measurement/understanding-insulation-resistance-testing

http://www.chauvin-arnoux.com/sites/default/files/D00VEC36.PDF

[Jim Port]

That isn't aluminum clad copper, that is "tinned copper".

The copper reacted with the rubber insulation, so the copper wiring was "tinned" to keep the copper separate from the rubber.

Tinned copper was a great conductor, the issue now (meaning 'nowadays') is that the rubber insulation has likely dried out and is hard, brittle, cracked, and not much good anymore.

I would recommend that an electrical contractor verify the condition of the rubber insulation to make sure the insulation is still good.

http://www.ecmweb.com/test-amp-measurement/understanding-insulation-resistance-testing

http://www.chauvin-arnoux.com/sites/default/files/D00VEC36.PDF

Agree, tinned copper.

There was a copper clad aluminum, but this pre-dates that.

[Jim Robinson]

What era was the copper clad aluminum? I don't think I've come across that one yet.

[Gunnar Alquist]

What era was the copper clad aluminum? I don't think I've come across that one yet.

Hi Jim,

I believe it is concurrent with the aluminum from the lat 1960s-early 1970s. I have never seen it either, but a local colleague saw it once (or claims to).

[Rollie Meyers]

Hi Jim,

I believe it is concurrent with the aluminum from the lat 1960s-early 1970s. I have never seen it either, but a local colleague saw it once (or claims to).

My guess it was a later attempt at keeping market share, had the "economy" of Aluminum, and the ease of terminating like copper since CO/ALR rated devices would not be required. Some wiring devices are marked "copper or copper clad wire only".