If your house was built or renovated between 1965 and 1973, it may have aluminum wiring. If it does, it needs attention immediately. Aluminum wiring can be a fire waiting to happen, but there are steps you can take to remove the risk.
When the cost of copper shot up in the mid-60s, builders turned to aluminum; it was a good conductor, and it was a lot cheaper. So why the danger?
Aluminum expands and contracts more than copper as it heats and cools â€“ which is what happens when current runs through wire. With aluminum, the expansion is so great that it can actually push contact screws away, leaving a gap when it cools; or it can disrupt connections with other wires inside a twist-on connector. When there’s a gap between two wires, arcing occurs as the current jumps the gap. That little spark can be the start of a big fire.
Another problem with aluminum is its oxidation â€“ the coating that occurs on the metal when exposed to air â€“ that is, at connections. Aluminum oxide’s a poor conductor. When current gets roadblocked, the connection heats up. It can start to melt or burn the outlet.
On top of that, aluminum’s less flexible than copper, and breaks more easily.
The first generation â€“ right up to 1972 â€“ was the worst culprit, but that’s the bulk of houses with aluminum wiring.
You can identify aluminum wiring by it’s color â€“ it’s silver â€“ and sometimes by the word aluminum or a brand name on the sheathing. A higher gauge of wire, such as #12 on a 15-amp circuit, might also indicate aluminum, since aluminum was required to be one size larger for a given circuit.