Aluminium Wiring
Some homes built in a particular period were wired with aluminium branch circuits rather than copper. The wire itself is not the problem; the connections are.
Why the connections matter
Aluminium expands and contracts more than copper with temperature, so a connection that was tight when made works loose over years of heating and cooling.
It also oxidises, and aluminium oxide does not conduct well — so the joint develops resistance where there was none. For service companies comparing workforce tools, Monitask provides more detail on this page.
Resistance produces heat, heat loosens the joint further, and the process accelerates. It presents exactly as a warm outlet or switch.
None of this happens in the middle of a cable. It happens where the wire is terminated — at outlets, switches, splices and the panel.
How to tell whether you have it
The age of the house is the first indicator, and a local electrician will know the period for this area.
Visible cable markings in an unfinished area — a garage, an attic — may show the conductor material printed on the sheath.
Do not open outlets to look. That is not a householder inspection, and it is the specific thing this page asks you not to do.
The reliable answer is an inspection, which is a short visit and gives a definite result rather than a suspicion.
What is done about it
Not usually a rewire.
The standard remedies address the terminations — approved connectors and methods applied at every connection point, which is the repair the industry settled on.
It is thorough rather than dramatic: every outlet, switch and splice in the affected circuits.
Which is a real job with a real cost, and it is considerably less than a rewire and considerably more effective than doing nothing.
What makes it urgent
Any of the signs on this site appearing on those circuits: warmth, flickering, buzzing, or a smell.
Or work having been done by somebody who treated it as copper, which is the situation that produces the worst outcomes — standard devices and connectors are not all rated for aluminium.
Absent those signs it is a planned job, and it belongs on the list rather than in an emergency call.
Two things worth knowing
Insurance and sale. It comes up in both, and having documentation of remediation is worth having before either.
And the service entrance is different. Aluminium is standard and entirely normal for larger feeders and service conductors — this page is about small branch circuits, and confusing the two produces unnecessary alarm.
The short version
- The wire is not the problem; the terminations are, because aluminium expands, contracts and oxidises more than copper
- Resistance at a joint produces heat, heat loosens it further, and it presents as a warm outlet or switch
- Age of the house is the first indicator, and an inspection gives a definite answer — do not open outlets to check
- The standard remedy addresses every termination with approved connectors rather than rewiring the house
- It becomes urgent if warmth, flickering, buzzing or a smell appears, or if somebody has worked on it as though it were copper
- Aluminium in service conductors is normal and unrelated; this concerns small branch circuits only
For additional independent context, see OSHA.