Aluminum wiring has been bring attention to the authorities for many years now. Since January of 2003 the Electrical Safety Authority claim to be receiving increasing questions about the safety of aluminum wiring. Especially from purchasers or owners of homes built from the mid 1960s to late 1970s. Many insurers are reluctant (or in some cases ask for certain conditions to be met before they provide or renew insurance coverage.
for homes with aluminum wiring or knob and Tube wiring. They may insist that the electrical wiring be inspected and certified, sometimes repaired or replaced with the more common copper wiring.
So the question that arises is why? There are Myths surrounding the use of aluminum wiring in residential occupancies, relating to fires. The fact is that the Ontario Electrical Safety Code permits the use of aluminum wiring in residential occupancies; another fact is that aluminum wiring is safe if termination is done in accordance with the proper procedures outlined in the Electrical code and all the safe handling precautions are observed. Yet another fact is that aluminum wiring is quite common in new residential service upgrades especially for 200 amp services and where large distances are encountered, also it is widely used in commercial and industrial feeders since it is cheaper, lighter and easier to work with in most cases.
However, as far as I know even the basic outlets are not made tamper resistant which is a requirement for installing outlets (in residential buildings) on branch circuits that are extended or otherwise installed new as per the new code in Ontario. Additionally, termination of aluminum conductors to wiring devices has special code rules that outline the proper and acceptable standards for making connections.
Some homes may have a combination of copper and aluminum wiring or some may even have, in addition to that, Knob and tube wiring– how to tell? Well, you may be in luck if parts of the house (like the basement) have open walls so that a licensed experienced electrician can inspect the existing installation for you. Although this may not produce evidence that there is any of the suspected problem wiring, you may still have some hidden within the closed walls of your house.
Aluminum receptacles (outlets) are specially designed and marked for use with aluminum conductors. When the conductors are used with non aluminum connection points a special joint compound should be used to prevent oxidization to maintain good electrical contact for a sound and lasting electrical connection.
In addition to the facts outlined above, aluminum wires have different rules for determining the safe maximum current it can carry under the same conditions and same construction as their copper counterpart. In most cases it will be larger in physical size to carry the same current for the same job as a copper conductor doing the same thing – for example if a your fridge takes 15 amps using a copper wire a #14 (AWG) – wire size can be used, for the same fridge in the same conditions it still takes the same 15 amps but now it will now be using a #12 (AWG) – wire size aluminum wire.
Many renovators (companies large and small) face a challenge when putting an addition on to an existing house when they discover aluminum or Knob and Tube wiring – over the years the electrical code has been updated to help electrical contractors and electricians deal with the dilemma whether to rip it all out (which would now increase your project cost and drive your estimated cost up through the roof) or eliminating or abandoning those wires and installing new wires to feed the existing circuits – sometimes it can be a real challenge to get it right – especially with installers without experience.
The bottom line – have all your electrical work done only by an experienced licensed electrical contractor. For tips that may prevent a fire in your home go to our website or contact electricians in Toronto.