Century Electric Specializes in Aluminum Branch Wiring

Many houses built between 1964 and 1976 have aluminum branch circuit wiring. (Branch circuits are the wires that run to each room from the service panel.) This product was developed because copper became expensive and hard to get during the Vietnam War.

Aluminum is the third-best conductor of electricity, behind copper and gold. It was an easy alternative to copper wire.

However, this wiring turned out to be a fire hazard. The connections between the wire and a light switch or outlet can arc, causing a spark that can burn the connection point; fire can spread from there.

There are repairs that all but erase the threat of a fire. The Consumer Product Safety Commission (CPSC) recommends either that the aluminum wire be replaced with copper or that the connections be repaired using specific methods.

Repair is less expensive than replacement, although it can still cost thousands of dollars in a standard-size house. Every connection between the aluminum wire and an outlet or light switch needs to be retrofitted using a piece of copper wire and a connector.

The CPSC has approved only one retrofit technique, called a COPALUM connector, used with a special crimping tool. However, in practice, many more of these systems seem to have been retrofitted with a product called the Ideal Twister Al/Cu (aluminum-copper) connector, a purple wire nut filled with a non-oxidizing compound. The Twister complies with the National Electrical Code and has been Underwriters Laboratories-listed. These repairs are less expensive than COPALUM repairs.

All work on aluminum wiring should be done by licensed or certified electricians. Improperly repaired wiring is a fire hazard. Aluminum wiring is most easily identified at the main electrical panel by a trained professional.

1960's - 1970's

Knowing the difference between Aluminum Branch Wiring and Copper Clad or Copper Wiring could help you protect your home from fire. Building Specs home inspectors are trained to locate and inspect aluminum wiring in your home. Aluminum branch wiring was used during the 1960's and 1970's for the wiring of receptacles, switches and devices throughout many homes.

This single strand branch aluminum wiring has been implicated in a number of house fires. The actual cause of these fires was not the aluminum wire itself, but was the result of 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 thus there is a tendency for the connections to become loose at the devices and junction boxes. Oxidation will build up between the loose connections, causing an increase in the amount of heat generated, which then poses a potential fire hazard.

Many individuals believe that the aluminum wiring should be removed and replaced with copper. This is not always necessary, and there are approved or recognized methods for making the system safe. If single strand aluminum wire is present (#12, #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 according to the Consumer Product Safety Commission, may pose an even greater fire hazard and should be replaced.

Approved methods include:

UL Listed purple wire connectors with copper pigtails CO/ALR Connectors or Devices Crimped Pigtails (i.e. AMP Copalum connector) If you are a Home Inspector, do not open any junction boxes or devices to verify proper connections, you become liable! All connections throughout the house must be verified by an electrician. 
Multi-stranded appliance wire or entrance cable is not included as a potential source of problems. It is still used and accepted. Look for antioxidant paste at panel connections for these wires and cables.

Copper Clad Aluminum

Copper Clad Aluminum is easily mistaken for copper. It does not have the same problem with oxidation build up as aluminum. It is typically a #12 wire and still needs proper devices with the larger screw heads or approved pig tailing methods. To identify Copper Clad Aluminum, look for a silver color at the ends of the wires where they are connected to the grounding bar. Copper Clad Aluminum can also be identified in the attic or crawlspace, or other locations where the wiring is visible, by looking for the identification on the wire sheathing, i.e. CU Clad AL.

When was aluminum wiring used in homes?

For over 100 years, the material of choice for residential branch wiring has always been copper, but when the price of copper spiked in the mid 1960’s, aluminum wiring was sometimes used as an economical alternative. By the mid 1970’s, inherent weaknesses were determined in aluminum wiring that led to its disuse.

It may surprise you to learn that there are an estimated 450,000 homes in Canada with aluminum branch wiring.

Is aluminum wiring safe?

Aluminum branch wiring in homes was installed the very same way as copper. Typically, aluminum branch wiring was connected at the electrical panel, and at the other end, to an electrical device or terminal. The behaviour of aluminum wiring at the device or terminal has been the focus of the issue, and not the wire itself. 

When aluminum branch wiring was introduced, the wiring material changed but the same copper devices were used. When electricity flows through either metal, it causes it to expand and contract. Aluminum and copper have different expansion properties. When the two different metals are connected, the differences in the expansion properties can cause the connection to become loose. Loose connections can result in sparking, arcing oxidation and heat buildup, all of which are safety hazards.

Fortunately, the problems associated with aluminum to copper connections are now well understood.

How to tell if you have aluminum wiring?

The only way to tell if you have aluminum wiring is to inspect the electrical branch wiring system. If you’re not comfortable around electricity and wiring then call in a pro. It’s a small investment to have a licensed professional do the work for you.

The first place to look for aluminum wiring is at your electrical service panel. By removing the cover and visually inspecting the exposed end of each wire connected at the panel, look for aluminum coloured wires. You’ll notice that there is a mixture of large and small gauged wires installed in the panel. Larger (thick) gauged wire will be used for feeding the heavy loads, like electric ranges and dryers, while the smaller gauged  (thin) wire will supply electricity to the lower branch lights and wall plugs.

The electrical supply lines that enters our homes is usually aluminum, as is almost the entire power grid.

You may find that copper branch wiring has been installed throughout the home. Alternatively, you may observe the presence of aluminum branch wiring to all, or part of the home.

Large aluminum gauged wiring (220-volt) serving major appliances is considered acceptable in most cases because:

• Normally there are only two connection points in the circuit
• These connection points or are of a different design than that found in a household receptacles
• The wire connection usually is straight without a sharp bend or crimp
• Major appliances and their currents are more likely installed by qualified professional electricians
• During the late 80's, manufacturers made improvements on the aluminum wire itself by adding a small percentage of other performance enhancing metals

Aluminum is an excellent choice for main distribution wiring, but not for lower branch circuit wiring.

Another way to determine the presence of aluminum branch wiring is to inspect the branch wiring sheathing. You may be able to see wires entering the panel or perhaps you can look between open floor joists or up in the attic.

Aluminum wire sheathing made before May 1977 will be marked with

·        The word  ALUMINUM

·        An abbreviation -  ALUM, or AL.

Aluminum wire sheathing made after May 1977 will be marked with

·        The word  ALUMINUM

·        An abbreviation – ALUM, ACM, or ALACM

Aluminum wire sheathing may be marked with the manufacturers’ name:

·        NUAL

·        STABILOY

·        ACM

 Items that indicate electrical problems and requiring inspection are:

·        arcing or sparking at an electrical device - unusual sounds such as sizzles or buzzes

·        an item is hotter than it typically should be to touch

·        breakers or fuses continually trip or blow

·        equipment or wire is damaged

·        discoloration of receptacle or light switch cover plates

What can I do if my home has aluminum branch wiring?

If you have lower aluminum branch wiring, the correct way to get started is to have your electrical system assessed by a licensed pro.  

If your aluminum wiring is terminated on devices that are currently approved for use then most likely all that needs to be done is for the electrician to inspect all connections and possibly apply some anti-oxidant. Still, this is considered a temporary solution.

If the aluminum wire is not terminated at properly approved devices, then one you may elect to choose one of the following options:

·        Replace all devices to the current standard. This is considered a temporary solution.

·        The correct and lasting solution is to eliminate the aluminum wiring in its entirety.

Short-term fixes are least effective as they are only temporary and need to be checked every few years for further system deterioration. Doing the math, and using the short term or Band-Aid fixes, don’t return your investment as effectively as full replacement.

Aluminum wiring and age

Now that lower branch aluminum wiring is more than 40 years old, it’s long overdue for and inspection if you haven’t had one.

While it might be tempting to believe that a home with aluminum wiring is safe because the wiring hasn't caused a problem for 30 or 40 years, that is a risky misconception. The longer aluminum wiring connections are left uninspected and allowed to deteriorate, the more likely a problem will occur.

How to replace aluminum wiring

You can do some of the work yourself or you can hire a pro. Sure, it’s possible for a determined and skilled homeowner to pull the wiring, but hiring a pro is really the way to go. The experts are experienced in minimizing drywall damage and carefully fish in new wires. Seek out a specialist with years of experience doing just this for the best results.

Cost for replacing aluminum branch wiring

With over 450,000 homes in Canada with aluminum branch wiring it would be convenient to have a simple formula for pricing out the cost of replacing aluminum branch wiring. Since there are so many variables in construction techniques a simple formula is impossible to devise.

The cost of replacing your aluminum wiring in your electrical system can be likened to the cost of several routine home maintenance items such as re-flooring your home for putting on new roof shingles. If you are in the position to re-wire the home, and you weren’t prepared, it’s an unfortunate position to be in. But it really is similar to other maintenance items, perhaps one you didn't expect.

Replacing aluminum wiring is a good investment in your home. You will realize peace-of-mind and increased value to your home.