Aluminium Wiring in Sydney Homes: What You Need to Know

During the mid-1960s, the global price of copper spiked sharply due to high demand from the electronics and construction industries. Aluminium — lighter, cheaper, and readily available — was adopted by electrical contractors across Australia as a direct substitute. Homes built or rewired between approximately 1963 and 1978 were the most likely to receive aluminium branch circuit wiring.

The practice was phased out during the late 1970s and early 1980s as the fire risk became better understood and copper prices stabilised. Today, aluminium is still used in electrical installations, but only for large-gauge cables — service mains, sub-mains, and main switchboard feeds — where its different expansion properties are well understood and managed. Branch circuit wiring (the cables running to your power points and light fittings) is now exclusively copper in new work.

Aluminium wiring is not inherently dangerous when new and properly installed. The problem develops over time due to a combination of physical properties that differ significantly from copper.

Aluminium expands and contracts more than copper when it heats and cools with electrical load. Over years of cycling, connections — particularly at power points, light switches, and junction boxes — gradually loosen. A loose connection creates resistance, which creates heat, which accelerates the loosening further. This progressive cycle can eventually produce arcing and ignition of surrounding materials.

Aluminium also oxidises when exposed to air. The oxide layer that forms on aluminium is an electrical insulator (unlike copper oxide, which still conducts reasonably well). At connection points, this oxide layer increases resistance and heat generation.

Studies by Standards Australia and international bodies have found that homes wired with single-strand aluminium branch circuit wiring have a significantly higher incidence of overheating at connection points compared to copper-wired homes of the same age.

Aluminium wiring can often be identified by a licensed electrician during an inspection, but there are some indicators you can look for yourself:

• Age of the home — if your property was built or significantly renovated between 1963 and 1978, aluminium wiring is possible.
• Silver-coloured conductors — if you can safely see bare cable ends in your switchboard, copper is orange-brown and aluminium is silver-grey.
• AL markings — aluminium cables are often marked "AL" on the sheathing. Copper cables marked with nothing, or "CU".
• A building or electrical inspection report noting the presence of aluminium wiring.

The most common problems in homes with aluminium branch circuit wiring relate to connection points at power points, light switches, junction boxes, and at the switchboard.

• Warm power points or light switches — a sign of elevated resistance at the connection point.
• Flickering lights — particularly when a load (heater, kettle) is turned on nearby.
• Burning smell from power points or switches — this is an emergency. Turn off the circuit at the switchboard and call an electrician immediately.
• Power points that no longer work, or circuit breakers that trip without obvious overload.
• Scorching or discolouration around switch and power point faceplates.

There are three main approaches, ranging from management to full replacement. The right solution depends on the extent of the wiring, the age and condition of the connections, and your budget.

Remediation with CO/ALR devices: Replacing all switches and power points with devices specifically rated for aluminium wiring (marked CO/ALR in the US, though similar devices are available in Australia) reduces the risk at the most vulnerable connection points. This is a partial solution that requires all devices on affected circuits to be upgraded.

Pigtailing with COPALUM connectors or equivalent: A licensed electrician splices a short length of copper wire onto each aluminium conductor at every connection point using a special crimp connector rated for aluminium-to-copper joints. The power point or switch then connects to the copper pigtail. This is an approved remediation approach but is labour-intensive.

Full rewire with copper: The most comprehensive and permanent solution. The aluminium wiring is replaced entirely with copper in every circuit. This is disruptive and expensive but eliminates the risk completely and brings the electrical installation to current standards, including modern RCD protection and circuit breaker sizing.

There is currently no NSW regulation requiring homeowners to replace existing aluminium wiring that is in otherwise satisfactory condition. However, whenever a licensed electrician carries out work on a circuit that contains aluminium wiring, they are required to assess the connection points they disturb and remediate as necessary.

If you are having any electrical work done on a home with aluminium wiring, inform your electrician before they start. They can include a connection point audit in the scope of work and advise on the most appropriate remediation strategy for your property.

The presence of aluminium wiring should not automatically disqualify a property — many older Sydney homes have it and present no immediate problems. What matters is the current condition of the connections and whether the installation has been appropriately managed.

Before purchasing, commission a licensed electrician to carry out an inspection specifically focused on the aluminium wiring and all connection points. Factor the cost of remediation — whether pigtailing or a full rewire — into your purchase negotiation. A full rewire of a typical Sydney house costs between $8,000 and $20,000 depending on size and complexity.

Disclose the presence of aluminium wiring to your insurer. Some insurers will require proof of a recent electrical inspection or impose conditions on coverage for homes with aluminium branch circuit wiring.