There is a lot of controversy surrounding single strand aluminum wiring even among home inspectors, with good reason. Not to mention the issues that can arise on the insurance side.
Most homes with widespread single strand aluminum wiring were built between 1965 and 1972. However, aluminum is still used in a lot of areas still today. Aluminum wiring was used mainly because it is a lighter weight material and is much less expensive than it’s more durable and more conductive counterpart, copper. Copper is now much more widely used than aluminum because it is more reliable. For the sake of this specific issue and post, we will only be talking about single strand aluminum wiring. Multi-strand aluminum can have completely different properties.
Common Problems With Aluminum Wiring
Typically, an oxide or rust forms on aluminum due to a chemical reaction to oxygen. A white substance can form on aluminum that restricts conduction of electricity. This process can also cause the aluminum to overheat.
Copper can also develop an oxide but it does not typically cause conduction to lessen.
#2 Soft Material
When a home is wired, the wiring is cut and stripped. Because aluminum is a soft material, sometimes it can become damaged.
#3 Expansion and contraction
When electricity flows through wire it heats up. With aluminum, its composition causes it to expand when it heats up more than other materials. Then after it cools down, it contracts. Over time, this will cause the screws and lugs near the wire to loosen. This in turn can cause arcing which is a fire hazard.
My Home Inspector Found Aluminum Wiring. Do I Need to Have It All Replaced?
Tearing up walls to replace all the wiring is an expensive task to say the least. Here are the most common options for aluminum wiring.
#1 Rewire the home
You could have the home rewired. However, this is going to be expensive.
This is a common repair for aluminum wiring. The main issues with aluminum wiring is at the connection. These could be at switches, outlets, junction boxes etc. . Pigtailing puts a copper wire at the connection and then connects to the aluminum. However, the connection must be a special connection with special equipment. You can’t just connect it directly. There are a few different methods of pigtailing:
- Twist-On Nuts
- These should only be the copper to aluminum specialized nuts. Be careful, these are not allowed in some areas!
- COPALUM (Copper Aluminum Connectors)
- These are specialized connectors that must be crimped with a special tool.
- This type of connector actually uses specialized screws to connect to two materials together.
#3 Aluminum Specific Outlets and Switches
There are a few manufacturers that make outlets and switches that are specifically designed to account for the unique characteristics of aluminum.
Aluminum Wiring and Insurance
Many home owner’s insurance companies will not write policies for homes with single strand aluminum wiring. This can be a big consideration when weighing options.
The US Consumer Product Safety Commission says that a home that has aluminum wiring is 55 times more likely to catch fire than other wire types. Remember, most issues that arise from aluminum wiring are at the connections. These connections could be at switches, outlets, junction boxes etc. If you think about the number of connections in the average home, you can see the risk.
Don’t ever try to fix electrical issues by yourself. You should always consult a licensed electrician before undergoing any electrical upgrades or repairs.