Copper or AL wiring.

4 Replies

Hello everyone.

Any pointers on finding out if wiring in a house is Copper or AL?

Owner said that when they bought the house 30 years ago they redid the wiring.

Do you all think it is AL it being 30 years ago?

Originally posted by @Jerryll Noorden :

Hello everyone.

Any pointers on finding out if wiring in a house is Copper or AL?

Owner said that when they bought the house 30 years ago they redid the wiring.

Do you all think it is AL it being 30 years ago?

 30-yrs ago puts you in the 1980s.   It would be less likely to find Al wiring in a residential property from that time (at least here).   It was more commonly used in residential from the late 60s through to the late 70s.

Just look at the wires, the encodings on the wire casing will tell you what's inside.  You can also look inside the panel (or have someone qualified do that) and see if there are any Al wires.

You can look at the other end (fixtures, switches, outlets) but this may not tell you as it was/is common practice to pig-tail copper onto Al to allow Cu fixtures and switches to be used (they are far cheaper).   If this pig-tailing is present and was not done properly, it can be a problem.

In fact, the AL-CU joint IS the safety hazard as it over heats and causes fire within the wall.

Open the subpanel cover and inspect the black wires going to each breaker (just look with a good flashlight).  You can tell copper from aluminum by the color

Originally posted by @Jeff B. :

In fact, the AL-CU joint IS the safety hazard as it over heats and causes fire within the wall.

Open the subpanel cover and inspect the black wires going to each breaker (just look with a good flashlight).  You can tell copper from aluminum by the color

 It's definitely one of the safety hazards - and, based on how poorly it is often done, probably the largest hazard - but around here it is also common to find copper fixtures on the end of AL wiring which can also work loose over time.