INSPECTOR INSIGHTS: ALUMINUM WIRING

Solid Aluminum Wiring conductors were commonly used for Residential wiring between 1969 and 1976.  Stranded Aluminum Wiring is still used today although generally only for Major appliances or Sub panel feed and entrance conductors for homes. Aluminum wiring has a few differences when compared to copper. First - the coefficient of thermal expansion i.e. when current runs through it and it heats up it expands more than copper therefore it wants to move more at connections. Second - when an oxide is formed such as when you strip it to make a connection, thealuminum oxide is a resistor to current flow whereas copper oxide is a conductor. Third - Aluminum wire is brittle in comparison to copper. It is difficult to bend and is susceptible to nicks or cuts such as when using a stripping tool. If you are buying a home in this age group be aware your insurance provider will likely have some requirements. Check with them on their specific requirements as they do vary across the industry. A review of the entire system may be required by them to obtain insurance.   

Only a qualified electrician or electrical contractor should work on aluminum electrical wiring. If you need to find an electrician just go to the BC safety authority or visit their website http://www.safetyauthority.ca and click the link find a contractor -http://www.safetyauthority.ca/contact/find-contractor
There is a right and wrong way to work on aluminum wiring. To extend a circuit there are special connectors typically called marrettes that are specific for this application. Also switches and receptacles approved for aluminum will specifically state such. Finally an anti oxidant is typically applied to aluminum conductors. Switches and receptacles are more expensive but are designed for aluminum and tested to be safe.
As a homeowner there are a few things to watch for as you live in the home.

1. Do you notice there is intermittent continuity in a light or receptacle? Sometimes the light/receptacle works and sometimes it appears dead. This might be an indication of a loose connection.
2. Does the faceplate seem hotter to touch than normal? This might be an indication of a poor connection. 
3. Do you notice the distinctive smell of burning or melting insulation? 
4. Do you hearthe distinctive sound of electrical arcing? 
If any of these are apparent. Call an electrician!
Finally periodic review of your electrical system say every 5 years may be wise to avoid unpleasant surprises. Check with your electrician on this.

Roland Klann
RHI BC Licence 47331
HomePro Systems2000 Inc.
604-240-3314
www.Homeprosystems2000.ca