Aluminum Wires

During home inspections customers often ask me : “Does this house have aluminum wires? Is it safe?” “The house has aluminum wires, can this house still be bought?” I think it is necessary to talk about the knowledge of aluminum wires , so as not to misunderstand the aluminum wire.

The history of aluminum wire
Since humans had electricity, copper wires have been widely used. However, in the mid-1960s, due to the soaring price of copper, aluminum wires were widely used in North America due to lower price.

There are rumors that “aluminum wire has been fully recalled”, “aluminum wire is now completely banned”, “aluminum wire must be replaced with copper wire” However the facts are: Aluminum wire is also being used now. As long as the material meets the requirements and is installed correctly, there is no problem and it fully meets the electrical industry standards.
The problem of aluminum wire:
Why do people worry about aluminum wires in their houses? That’s because the aluminum wire does have some problems during use:

  • Soft and easy to fold: Aluminum wire is not as tough and flexurally as copper wire. Therefore, be extra careful when installing the aluminum wire, not to damage the aluminum wire.
  • Creep: Current passing through the aluminum wire will cause it to heat up and expand. When the aluminum wire expands and contracts repeatedly, it will eventually cause the interface to loosen, causing local overheating or disconnection.
  • Rust: the copper wire rusts into green copper oxide, which also has good conductivity; but the aluminum wire rusts into white alumina, and the electrical conductivity is further reduced, causing local overheating of the circuit.

Conductivity of aluminum wire:
In the process of transmitting current, aluminum wire has a higher resistance than copper wire of the same thickness. For example, we generally use 14-gauge copper wire, but if we use aluminum wire, we must use 12-gauge wire. (The smaller the number, the thicker the line).

Solution to aluminum wire problem
The aluminum wire problem occurs at the interface, such as socket or switch interface, light interface, electrical interface, and power control box, etc. Therefore, the key to solving the aluminum wire problem is that these interfaces must be able to connect to the aluminum wire.
Many interfaces on the market now can be connected to both copper wire and aluminum wire: CO/ALR
• Small socket marked with CO/ALR or AL-CU
• Large socket marked with AL-CU or CU-AL (>20A)
• Switch marked with CO/ALR
• Wiring screw cap marked with AL-CU or CU-AL
• Air switch box/distribution panel marked with AL-CU or CU-AL

Home insurance issues
If you have aluminum wires in your house, the most worrying thing is insurance. Some insurance companies believe that the aluminum wire is a fire hazard and therefore refuse to insure; while some insurance companies require the homeowner to issue an inspection certificate from a professional electrician or an authority.
In conclusion
Aluminum wire does have many problems, but aluminum wire is not banned even though the installation and use of aluminum wire have special requirements.

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