Aluminum Branch Wiring in Older Phoenix Homes: What to Know

What the actual problem is

Aluminum conductor is not inherently dangerous — large aluminum feeders are used routinely today, including on many perfectly good service entrances. The specific concern is small aluminum wire on 15- and 20-amp branch circuits, at the terminations: the places where wire meets outlet, switch or splice. Aluminum expands and contracts more than copper, oxidizes differently, and is softer, so connections that were tight on installation day can loosen over decades of Phoenix thermal cycling. Loose connections make heat.

How to tell if you have it

Cable jackets in the panel are often printed with the conductor material, and the wire itself is silver rather than copper-colored. Devices listed for aluminum are marked CO/ALR. Do not go pulling outlets apart to check — have it identified during an inspection, when the panel is already open and de-energized.

Repairs that are actually approved

The accepted approaches are pigtailing aluminum to copper using connectors listed and labelled for that purpose and installed per their instructions, replacing devices with ones rated CO/ALR, or rewiring the affected circuits in copper. What is not acceptable: ordinary twist-on wire nuts on aluminum-to-copper, standard outlets on aluminum conductors, or anti-oxidant paste used as a substitute for a listed connection method.

Why it comes up when you sell

Home inspectors flag it, and some insurers ask about it. Having documented, properly performed remediation is far better than a surprise during escrow. If you are planning to sell in the next few years and you know the house has aluminum branch circuits, dealing with it on your schedule is much less expensive than dealing with it on a buyer's.