In Ontario, between 1968 to 1976 many electrical contractors used aluminum wire for new homes that were being built. Aluminum wire is safe to be used, but it is the connections that may cause problems. When working with aluminum wiring, certain precautions must be taken because aluminum has different properties than copper, which is the conductor now used in standard wiring. The two react differently when under electrical load, expanding and contracting at different rates, which may cause the connections to become loose. Loose connections can result in sparking and arcing, and the possibility of a fire.
Another concern when dealing with aluminum in your home wire is oxidation. Oxidation is the build-up of a thin layer of aluminum oxide which creates a thin insulating layer that will increase the electrical resistance of the conductor, causing it to become brittle and eventually deteriorate the connection. To address these potential hazard we need to use the proper products, such as aluminum-rated connectors that will accept either copper or aluminum wire in conjunction anti-oxidant paste.
An experienced electrical contractor with knowledge of aluminum wire installations should be offering three possible solutions:
“Pigtail” the aluminum to copper wire using the correct aluminum-rated wire nut or crimping device.
Usually in an electrical device box we will also find a ground and neutral wire alongside the “hot” power wire, so with this method you will have two more connections in the box. So while this method would be an acceptable by electrical code, the cost of replacing the device box (“Box Fill” due to too many wires) and our experience with the failure rate of the additional connections, has taught us that this method is not the best choice. Therefore, we at Solutions Electrical will not offer this service.
Replace the devices.
All of the devices (switches and receptacles) are replaced with approved devices that are rated to accommodate aluminum wire. These devices are known as Co/Al (Colar) and ensure that both the aluminum and copper connections are tightened correctly. The connections will be required to be tightened again – we recommend every 4 years. With the above suggestion we would highly suggest a “Test and Troubleshoot” for the whole home, to give you the peace of mind that the home is as electrically safe as it can be.
Rewire the whole home.
This would be the best choice, yet the most expensive. Most of us have a friend, or know of somebody that had Knob and Tube wiring from a century home perhaps, and their insurance company gave them a short timeline to have the home rewired to a safe standard. Well aluminum wire is on the road to facing the same fate. Currently, insurance companies are requesting documentation from an electrical contractor stating that the home is safe. In our opinion, homeowners should be budgeting for this project. When rewiring a home, it is not just the electrical contractor’s invoice to consider, you will need a general contractor to patch, prime and paint the ceilings and walls following the rewire process. The cost of the rewire will vary, with many variables such having a finished basement, the style of home, how many levels the house has and the amount of furniture in the home that the electricians will have to work around.