Aluminum Wiring

Does The House You Are Buying Contain Aluminum Wiring?
 
 
Many houses built in the late 1960s and first half of the 1970s may have been wired with aluminum wiring.

Here in Peterborough we do find aluminum wiring.

 
Your home inspector needs to look for and report the presence of any aluminum wiring he/she finds.
 
Aluminum service entrance cables are still widly used and installed today and they are not the issue. 
 
The issues with aluminum wiring seem not even be with the circuit wiring itself, but rather with the connections made between the aluminum wiring and other wiring, switches and receptacles.  As current is moved through aluminum wiring, it expands and contracts differently than does the copper wiring, which over time can create loose connections.  Loose connections can create electrical hot spots, including arcing, which is a fire hazard and obvious safety issue.  Light switches, for example, must be the correct ones specifically rated for aluminum wiring.  For example, when a light switch or receptacle rated for and connected to aluminum wiring is replaced, one must ensure that the proper aluminum rated hardware be installed.  This is often overlooked and creates a safety issue.
 
THE HOME INSPECTION
 
As a home inspector, I look for aluminum wiring, particularly in homes that were built during the specific time period when it was widely used.  If found, I remove a sample number of light switch and receptacle cover plates, to see if the visible hardware is rated appropriately.  I do not pull out any switches or receptacles from their box because that could loosen a connection and create a fire hazard.  Due to this limitation, I recommend an electrical inspection of all wiring connections by an electrician. 
 
 
ELECTRICAL: With aluminum wiring, ensure light switch is compatible.
In the image above, you can see a switch rated for copper but not aluminum wiring.  When these switches are used for aluminum wiring there is a safety (fire hazard) risk.
 
 
In houses 30 years and older, one study has shown that the leading cause of house fires is electrical issues.  A house with aluminum wiring therefore deserves a thorough inspection to determine the overall condition of the electrical system.