Posted by: Doug Hastings, ACI
Updated: January 29, 2019
Due to the high cost of copper, electricians began using aluminum wiring between 1968 and 1974. This wiring can cause loose connections, overheating, and even house fires. Home inspectors need to know about this wiring and be able to inform homebuyers (or homeowners) of their options.
Determining whether a house is wired with aluminum is not as easy as it may seem. You might start by researching if the electrical panel was installed during the period when solid aluminum wiring could have been used. If you’re a seasoned home inspector or a certified electrician, you can check to see if the wiring actually is solid aluminum and if that wire has caused heat damage.
To start, look at the cut end of the wire to determine if it is solid or coated. Silver wiring is not necessarily aluminum—it could be copper wire with a tin coating. Similarly, copper wire may not be what it seems. Aluminum wiring was sometimes coated with copper to prevent a chemical reaction between the aluminum wire and its mounting hardware.
The main concern is aluminum wire alloys, produced between 1964–1981, expand more than copper wire when they get hot and shrink more when they got cold. This continual expansion and contraction causes loose connections, overheating, and eventually house fires.
The best solution is to completely rewire the home. This can be very expensive for the homeowner, so there is a code-approved alternative. Copper pigtails (a short copper wire) can be connected to the aluminum wires, creating a bond between the approved devices and the wire. This bond will stay secure and prevent overheating.
There are two devices approved to bond the copper pigtails to the aluminum wire. The best is a COPALUM connection, which is a form of cold welding. Homeowners should be made aware of the fact that only a trained and certified electrician using specialized tools should do this, and it is a costly process. The next best alternative is an AlumiCon connector. These connectors are a newer, simpler, and cheaper alternative to COPALUM. These devices also must be installed by a licensed electrician. Amateur installation of AlumiCon connectors is not approved because improper bonding of the wire to the connector can cause serious overheating.
Never let anyone attempt to connect the copper pigtails to aluminum wire with a wire nut. This method has been extensively used in the past, and it will absolutely cause overheating and possibly a house fire!
Aluminum wiring is an issue that should be addressed immediately. If you’re an ACI-certified home inspector, you can analyze the situation and inform homeowners or homebuyers about what needs to be done. Learn more about how Kaplan Home Inspection Education can help you with inspector licensing and certification preparation programs, home inspector professional development, and home inspector exam prep here.