Copper wiring with aluminum ground conductor

[Neal Lewis]

Here's a picture of aluminum grounds in a cloth wrapped wiring from the the fifties, think. The hot/neutral conductors are copper, but the grounds are aluminum. Besides the grounds spliced by a big wire nut, any issue with this wiring? I don't have a pic of the silver colored cloth covered cable.

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[John Kogel]

I had some similar wiring recently in a 1959 house. Two out of 10 or 12 circuits had Al grounds with copper hot and neutral. These cables were in a green cloth jacket. I surmised that a couple of circuits were added in the early 60's?

The issue of mixing copper with Al is obvious. In my case, the bus bars were not rated for Al connections, so the use of a wire nut would be correct, but only if the nut is rated for connecting Al to the copper jumper.

The other thing is the gauge of the grounds in these cables appears to be smaller than what you would want for an Al conductor. The grounds are not supposed to conduct, but if they do, they will also get hot.