Houses wired between the mid sixties and late seventies often have aluminium branch circuits. Buyers hear the word and assume a full rewire is coming. Usually it is not.
Why aluminium behaves differently
Aluminium expands and contracts more than copper as it heats and cools, and it forms an oxide layer that resists current. Over decades of load cycling, a screw terminal that was tight in 1974 works loose, resistance rises at the joint, and the joint runs hot.
The three accepted remedies
The first is a full rewire in copper, which is definitive and expensive. The second is pigtailing with approved connectors, where a short copper tail is joined to the aluminium with a connector rated for the combination and the device is landed on copper. The third is replacing every device with one rated for aluminium conductors. All three are legitimate; the right one depends on how many devices there are and whether the walls are open for other reasons.
The cable in the wall is generally fine. The terminations are the risk.
What we look for on the survey
Discoloured or brittle insulation at the terminals. Warm faceplates. Flickering on a specific circuit under load. Devices marked for copper only carrying aluminium, which is the single most common finding. We open a representative sample of boxes rather than all of them, then price the remedy against the count.
Insurance and disclosure
Some insurers ask about aluminium branch circuits and want evidence of remediation. Keep the certificate and the photographs of the completed connections; it is far easier than arguing about it at renewal.
Send us a photo
Open the panel door, photograph the label, and we will tell you the make, the age, and whether it needs replacing.