Was cloth insulated aluminum wiring used in the pre’60’s or is this a coated copper? Home was built in 1940 with electrical upgrade to breakers in 1972.
Thanks.
That vintage would be tinned copper.
Tinned wire was rubber coated and cloth covered and the coverings, when moved some, falls off. The aluminum wire that I’m aware of is plastic covered and started in the 60’s.
So I take it that the older cloth covered wiring is tin coated and the aluminum circuit wiring was all plastic coated.
Thanks Larry.
This house, built in the 40’s, had numerous electrical upgrades, including 2 aluminum branch circuits added in the 70’s. Also lots of 3-prong receptacles on 2-wire circuits. I hope the electrician is having fun with it. 
John Kogel
www.allsafehome.ca
