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Aluminum Branch Wiring

posted Apr 20, 2015, 7:43 AM by Troy LaPare

 Aluminum branch wiring was used during the 1960’s and 1970’s for the wiring of receptacles, switches and devices throughout many homes. It is particularly common in Subdivision homes built in the 1970s in the Erie County and Southern Ontario area.

Single strand branch aluminum wiring has been implicated in a number of house fires. The cause of these fires was not the aluminum wire itself, but was the result of something called thermal creep or improper connections. Aluminum does not conduct electricity as efficiently as copper and creates more resistance and heat. The wire also expands and contracts more than copper wire and can cause the connections to become loose at the devices and junction boxes. Oxidation will build up between connections, causing an increase in the amount of thermal energy generated, which then could cause fire.

Many individuals believe that the aluminum wiring should be removed and replaced with copper. This is not always the case, and there are approved or recognized methods for making the system safe. If single strand aluminum wire is present (#12, #10 Gauge, General Purpose Branch Wiring) it is important to install or verify proper connections of all devices and terminals throughout the house. Copper wire ends, known as ‘pigtails’, can be installed at all terminals. Wire nuts are not approved for pig tailing, and according to many licensed electricians, may pose an even greater fire hazard and should be replaced.

Keep in mind this does not apply to the main service lines that may be aluminum and are covered in thermal paste. These lines are connected directly to the service panel and thermal creep does not affect these heavy duty connections.


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