What you should know about
aluminum wiring
0
ROB PARKER, Special to QMI Agency
Saturday, June 16, 2012 12:00:00 EDT AM
Aluminum branch wiring was used during the 1960s and 1970s for the wiring of receptacles, switches and other
devices throughout many homes.
Aluminum does not conduct electricity as efficiently as copper and creates more resistance and heat.
Single-strand branch aluminum wiring has been implicated in a number of house fires; however, the actual cause of
these fires is not normally the aluminum wire itself but is the result of improper connections.
Aluminum wiring also expands and contracts more than copper, thus there is a tendency for the connections to
become loose at the devices (switches, outlets and breakers) and junction boxes. Oxidation will build up between the
loose connections, causing an increase in the amount of heat generated which can then pose as a potential fire
hazard.
Many people believe that aluminum wiring should be removed and replaced with copper. This is not always
necessary as there are approved or recognized methods for making these systems safe. If single strand aluminum
wire is present, (#12 or #10 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. Standard wire nuts are not approved for pig
tailing and should be replaced if present as they pose a fire hazard. Special wire nuts approved for aluminum and
copper connections must be used.
Do not replace devices with "copper only rated" devices because they could also be a fire hazard. There are
copper/aluminum rated devices available; however, they are much more expensive than the standard copper only
rated devices.
In the interest of safety, when it comes to aluminum wire, you need to contact a licensed electrician.
WARNING SIGNS OF UNSAFE ALUMINUM WIRING:
unusually warm or warped outlets and switch cover plates smoke or sparks coming from receptacles and switches
strange odours in the area of receptacles and switches untraceable problems with plug-in lights and appliances
periodic flickering of lights
CARE TO BE TAKEN WITH ALUMINUM WIRING:
Do not over-fuse aluminum wiring. The AWG (American Wire Gauge) rating of #12 aluminum wiring is equivalent to
#14 copper wiring. Both are rated for 15 amps, so use only the t5 amp rated glass fuse, cartridge fuse or breaker for
aluminum wiring stamped either 12/2 or 12/3.
Copper and aluminum should never be connected together except using special anti-oxidant paste and crimped with
approved clamp connectors. If you use twist-on connectors (wire-nuts or marrets), make sure they are approved for
use with aluminum wiring.
When purchasing replacement receptacles, switches or fixtures, ensure they're compatible for aluminum wiring.
Typically, receptacles approved for aluminum wiring will be stamped CO\.ALR, CU-AL or AL-CU indicating they can
be used for both copper and aluminum.
Do not use receptacles stamped with AL and a line through it. These receptacles are incompatible with aluminum
wiring.
As part of your preventive maintenance plan for the home, check switches and receptacles by removing the cover
plates and visually inspecting the wires for any signs of scorching, looseness, heat and/or odour.
Aluminum wiring is not handyman-friendly. If you suspect anything unusual, have a licensed electrician work on
circuits with aluminum wiring.
If you own a home with aluminum wire, you should have a licensed electrician check all connections every few years
to ensure they are tight and not oxidized.
If you're considering buying a home that has aluminum wiring, some insurance companies will ask for an ESA
(Electrical Safety Authority) inspection of the home, some will charge a premium to insure the home, or some may
even require that all connections be aluminum to copper pigtailed, the cost of which may be very expensive, before
they will insure the home.
Rob Parker is a registered home inspector with the Ontario Association of Home Inspectors and certified master
inspector with the National Association of Certified Home Inspectors who does home inspections in the London area.
Call him at ThameSpec Home Inspection Services at 519-857-7101, e-mailthamespec@rogers.com, or
visit www.thamespec-inspections.com.