If I find aluminum wiring during a home cottage or commercial inspection as a property buyer in Orillia, Gravenhurst, Bracebridge, or Muskoka  here are the facts about aluminum wiring that you need to know

During the early 1960's until late 1970's, aluminum wiring was occasionally substituted for more expensive copper wiring in branch circuits for residential electrical systems. This is still a common find during my home cottage and sometimes commercial inspections in Orillia Gravenhurst Bracebridge and Muskoka. The solid (single wire ) aluminum conductors were less reliable and their use was discontinued . Neglected connections in any circuits like receptacles, switches and light fixtures containing aluminum wiring can become increasingly dangerous as time passes. It is not the wire itself but the poor connections which can cause wiring to overheat, creating a potential fire hazard.

In addition to a potential fire hazard, the presence of aluminum wiring will affect your insurance policy. Be aware that some insurance companies have safety concerns about aluminum wiring, some companies will only grant insurance after an inspection and approval by the local authorities. Some companies will not offer insurance on houses with aluminum wiring. You should  discuss this with your agent

Aluminum wiring connections deteriorate through exposure to oxygen in the air which causes deterioration to the outer surface of  the wire, or oxidation. Aluminum wire is more easily oxidized than copper wire and as time passes, this causes problems with connections. When wires are poorly connected the resistance to electrical flow causes them to overheat, which creates a potential fire hazard.

Aluminum wiring connections also deteriorate  because of thermal expansion and contraction.
Much more than copper, aluminum expands and contracts with changes in temperature. Over time, this will cause connections to loosen. When wires are poorly connected they can overheat and electricity can jump small gaps creating arcing which creates a potential fire hazard. Even a 15 amp branch circuit in your home has enough power that an arc over a very small gap can and is used to wield steel.  The arc can generate heat levels far higher than that required to melt insulation or start wood burning.

Aluminum wiring connections deteriorate  through galvanic corrosion which is when two different kinds of metal are connected to each other a very low-voltage electrical current is created which causes corrosion. By the way, that's also why copper plumbing should not be directly connected to galvanized pipe without special fittings. Corrosion causes poor connections in both cases.

Aluminum wiring connections will also deteriorate through vibration.  Electrical current vibrates as it passes through wiring. This vibration is more extreme in aluminum than it is in copper and as time passes, it can loosen connections and when wires are poorly connected they overheat.

There are options for correction if your insurance will cover the home. Electricians in Gravenhurst, Bracebridge Orillia,and MUSKOKA are trained to do it.

All, yes all, every outlet, switch, light fixture, in the home should be taken apart, checked for arcing and signs of overheating, the stripped wires should be cleaned / sanded and an anti-oxidant paste applied.
If the home has a mix of copper and aluminum wire then all circuits should be checked for mixed use of copper and aluminum within the branch circuit. If mixed circuits are found then all of the junction boxes should also be checked and corrected if necessary. Junctions in aluminum and copper can be spliced at the connections using approved wire nuts (called "pigtailing").  Special copalum crimps can also be installed.

All Non-compatible devices must be replaced.   

This includes all outlets, switches, lighting fixtures etc. and replacements which must be rated for use with aluminum conductors. Prior home owners may have failed to replace devices with newer ones that are rated for use with aluminum conductors 

You can be sure that during my home cottage and commercial inspections whether they are in Orillia, Gravenhurst, Bracebridge or anywhere in Muskoka I will be watching for aluminum wiring and reporting the facts about it if I find any evidence of aluminum wiring because my clients need the facts to make an informed buying decision.