[Shop-talk] Aluminum and copper wiring

[Jim Stone]

Hi guys.  I am currently visiting my sister-in-law and offered to install a light switch for her; she has dusk-to-dawn outdoor lights that were installed by a handyman and wired without a switch.  She’d like to be able to turn them off, which is normally a pretty simple job.  However, her house was built in the early 70’s and has mostly aluminum wiring.  I just opened up the box where the handyman spliced in the circuit for the lights and he used a standard outlet made for copper wiring, not a CO/ALR rated one.  Aluminum going in; copper coming out.  No sign of arcing, fortunately, but I will do it right.  The current outlet has a copper ground wire and an aluminum one connected together to the ground screw.

I know using a CO/ALR outlet allows me to connect the (copper) light circuit to the original (aluminum) circuit, but I am not sure about how to do the ground wires.  I assume it is less critical with a ground wire than a hot one, but still…. I suppose I could simply not ground the lights or the new switch, but I am wondering if there is a better solution.

Thanks,

Jim