Aluminum ground wires ?

**Sam Morris** · 07-11-2018, 01:20 PM

Inspected home built in 1928 today (house has been rewired) and observed a couple branch circuits with an aluminum ground wire with hot & neutral wires copper, but have never seen this before. I'm guess the aluminum wire will not expand and contract if not connected to breaker. I don't see a reason for concern, how about anyone else ? Yes I do see the wires on bus bar stuffed under 1 screw.

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**Gunnar Alquist** · 07-11-2018, 02:17 PM

Originally Posted by Sam Morris

Inspected home built in 1928 today (house has been rewired) and observed a couple branch circuits with an aluminum ground wire with hot & neutral wires copper, but have never seen this before. I'm guess the aluminum wire will not expand and contract if not connected to breaker. I don't see a reason for concern, how about anyone else ? Yes I do see the wires on bus bar stuffed under 1 screw.

Hi Sam,

I have not seen mixed Al & Cu NM cable myself. Maybe someone else will chime in with a response.

I would think you're guess is correct. Since the equipment grounding conductor should not carry a current (except in the case of a ground-fault), then there should not be any expansion/contraction of the conductor. However, it still seems to me that the buss bar and switches/outlets (whatever devices the Al EGCs are connected to) should be rated Cu/Alr.

A couple of additional thoughts.

1) Could the current-carrying conductors be copper-clad aluminum? I have not run across copper-clad, but have read about it.

2) I certainly would make a mention of it in the report and let the client know that consulting with an electrical contractor could provide more information.

I am not seeing the multiple conductors you refer to (other than the doubled EGCs).

**Bill Kriegh** · 07-13-2018, 03:37 PM

Not at all likely that there's not any aluminum cable in that panel OR it's been replaced and alm. wire was used to extend short copper grounds with splices where you don't see then (VERY unlikely).

I'd bet closer inspection will find aluminum wire attached to some breakers and the neutral buss.

**John Dirks Jr** · 09-06-2018, 07:41 AM

The picture of the entire panel shows a number of splices. Perhaps that's where copper has been spliced onto aluminum? Did you trace the aluminum grounds up into the cable, where its enters the panel? Was there any printing on the cable jackets identifying it as AL?

**Jack Feldmann** · 09-06-2018, 10:44 AM

Sam,
I have also seen this in a panel. I could not find any aluminum wires anywhere else, except the grounds. In the panel I was looking at, there were no splices.

**Sam Morris** · 09-06-2018, 01:40 PM

Originally Posted by Jack Feldmann

Sam,
I have also seen this in a panel. I could not find any aluminum wires anywhere else, except the grounds. In the panel I was looking at, there were no splices.

Same here

**Rollie Meyers** · 09-08-2018, 05:00 PM

Since the NM cable sheathing is visible above the panel, looking what is written on them could provide some information.

**DanS26** · 09-27-2018, 06:42 PM

Look again.....those wires could be tinned copper. Looks like aluminum but is not.

**Gunnar Alquist** · 09-27-2018, 07:35 PM

Originally Posted by DanS26

Look again.....those wires could be tinned copper. Looks like aluminum but is not.

Tinned copper? Do you think so? The only time I run into tinned copper is with the old cloth-wrapped NM cable and those typically don't have equipment grounding conductors.