Background on Aluminum conductors.
The following is some background on the use of aluminum conductors. Aluminum conductors consist of different alloys known as the utility grade AA-1350 series (old technology) and AA-8000 series (new technology). AA-1350 has a minimum aluminum content of 99.5 percent. The alloy composition AA-1350 makes the conductor very soft and susceptible to oxidization in comparison to the AA-8000 alloy.
Many homes built in the 1960’s to 1970’s had AA-1350 aluminium wiring conductors used throughout the homes branch circuits. This was due to the high price of copper in relation to aluminum.
Problems with aluminum wiring.
In some cases poor workmanship at connections and indifference’s between copper, aluminum and the steel terminal screws at devices led to high resistance connections. It was at these high resistance connections that caused the potential for a fire hazard.
Reported problems with aluminum wiring have been related to the overheating and failure of aluminum wiring terminations. This is due to aluminum’s tendency to oxidize and its incompatibility with devices designed for use with copper wiring. Indicators that there may be a problem are warm cover plates or dis-coloration of switches or receptacles, flickering lights, or the smell of hot plastic.
It is important to note that if aluminum conductors are to be used for wiring a new replacement device that appropriate devices are marked CO/ALR, AL–CU” Or “CU–AL. Alternatively, copper “pig-tails” using a Al/Cu approved wire Connectors (these are usually purple for identification) and Anti‑Oxidant Compound should be used so that the connection point is not compromised.
Buying a older home.
Before purchasing a older home that has aluminum wiring it would be wise to contact your home insurance provider. In some case’s it may not be possible to get home insurance without a certified electrical audit performed by ESA. Some insures will charge a premium to insure the home, or some may even require that all connections be aluminum to copper pig tailed. To complete these tasks it is best left to a professional electrician as it is not an activity that should be considered DIY friendly. The cost to preform these tasks might be enough to consider walking away from the purchase of the home if other home purchase options are available.
Making Aluminium Wiring safe in your Home.
The best approach and only true way to fix aluminum wiring is to remove it and rewire the home with modern copper wiring. Due to the expense and time this takes many electrical contractors are taking a new approach to aluminum wiring by installing main electrical panels that incorporate AFCI breakers in conjunction with AL-CU rated devices. The AFCI breakers have the ability to sense a arc fault in your wiring. Although this method provides added protection for your home it is not a full solution. This is because a AFCI technology is not a 100% fix to the problem. The main issue is that because the AA-1350 alloy conductor is soft and oxidizes, connections loosen and become less conductive over time. This in effect causes the connection to heat up while a electrical load is applied. There isn’t always arcing taking place at the connection point as it fails which is what is required to trip the AFCI breaker. It should be noted that some older panels cannot be retrofitted with AFCI breakers. In this case the only option would be to install a dead front device at the electrical panel, or a AFCI receptacle after the breaker. This practice is now in common use because of updates to Ontario’s electrical code in 2012 and then again in 2015. The code 26-722 in the 2015 electrical code (Link to ESA website) dictates that general branch circuits located in a dwelling with sleeping quarters are to be AFCI protected. There are certain circuits that are exempted from this rule e.g. kitchens and bathrooms as they are GFCI protected but the take away is that AFCI use is here to stay and that when carrying out a home renovation or electrical panel replacement that is the time to consider making this update.
Where are we today with aluminum wiring?
Aluminum conductors are still used today but it is the newer AA-8000 series alloy. This alloy is generally only used for larger sizes of wire which can be found in overhead transmission lines, and main feeder circuits.
Before taking on any home renovation project it is important that you get the proper permits and follow your local electrical code to ensure compliance. Exercised caution should be used when working with aluminum conductors as not every state or province follows the same wiring methods. It is advised that you contact a electrical contractor or the issuing electrical authority for your area to see which rules and wiring methods apply to your situation.
You can find more information on aluminum wiring in Ontario by visiting ESA’s website. click the link -> Link to ESA website <-