How to Use Aluminum Wiring Safely in Your Home

What is Aluminum Wiring?

Aluminum wiring refers to electrical wiring that uses aluminum metal rather than the more common copper wiring. Aluminum wiring was used extensively in North American homes built between 1965 and 1973 because it is less expensive than copper and was in abundant supply.

However, aluminum wiring has been linked to certain fire hazards if not installed and maintained properly. The main risks come from loose connections and oxidization of the wires over time. So extra care needs to be taken if your home has aluminum wiring.

Dangers and Risk Factors of Aluminum Wiring

There are a few key factors that can make aluminum wiring more dangerous than copper:

• Oxidization - Aluminum oxidizes more easily than copper, forming a resistive coating on the wire. This increases resistance and can generate dangerous heat levels.

• Expansion/contraction - Aluminum expands and contracts more than copper with temperature changes. This can loosen connections over time. Loose connections generate heat that can melt wires or start fires.

• Incompatible connections - Connectors and terminations designed for copper wiring may not make ideal connections with aluminum wiring. This can accelerate loosening and oxidization issues.

In summary, the key risks are loose connections leading to overheating and electrical arcing, as well as resistance-related fire hazards from oxidization buildup on wires.

Signs You Have Aluminum Wiring

There are a few ways to determine if your home has aluminum wiring:

• Check the breaker box - Aluminum wiring will be connected to breakers marked CO/ALR, which stands for "copper/aluminum revised". Copper-only homes will not have these breakers.

• Examine the wire jacket - Aluminum wiring will be labeled as AL or aluminum. Copper wires are unlabeled or labeled as CU.

• Call an electrician - A qualified electrician can inspect your home's wiring and definitively determine if aluminum is present.

• Check your home's age - Homes built between 1965-1973 have a higher likelihood of having some aluminum wiring. But it's not a guarantee, so other checks should be done.

Precautions When Using Aluminum Wiring

If your home does contain aluminum wiring, here are some important safety precautions to take:

Use the Proper Connections

• Use only CO/ALR rated connections like wire nuts, switches and outlets. These are engineered to work safely with aluminum.

• Avoid copper-only devices - Things marked as CU or copper-only should not be used. The differing metals can accelerate oxidization.

Prevent Loose Connections

• Tighten connections - Check that all wire connections are tight according to manufacturer specifications, including at the breaker box.

• Use anti-oxidant gel - Special gels can help prevent oxidization and reduce loosening. Apply to all connections.

• Check wires regularly - Periodically check for loose, overheated or oxidized connections and re-tighten or replace as needed.

Consider Repairs or Upgrades

• Consider rewiring with copper - Though expensive, rewiring with copper wiring can eliminate the risks of aluminum wiring. Consult an electrician.

• Pigtailing - Attach a short section of copper wire along with the aluminum wire at all connections ("pigtailing"). This reduces oxidization and heating risk.

• Arc-fault circuit breakers (AFCIs) - These advanced breakers detect dangerous electrical arcing and overheating and cut power to prevent fires. Recommended for homes with aluminum wiring.

When to Call an Electrician

It's a good idea to have a qualified electrician inspect your aluminum wiring and advise you on any remediation needed. Call an electrician:

• If you have very old wiring that has not been inspected/updated.

• If you notice signs of loose connections, overheating, flickering lights, etc.

• Before doing any major electrical work like upgrades, repairs or remodeling.

• If you experience frequent tripping of AFCI breakers. This could indicate wiring issues.

• For a pre-purchase home inspection if you are buying a home that may have aluminum wiring.

Safely using aluminum wiring requires diligence and proper precautions. But done right, it can be contained as a fire risk. If in doubt, consulting an aluminum wiring specialist is recommended.

References:

• Consumer Product Safety Commission (CPSC). "Aluminum Wiring." https://www.cpsc.gov/Safety-Education/Safety-Education-Centers/Aluminum-Wiring
• Electrical Safety Foundation International (ESFI). "Aluminum Wiring - Problems and Repair." https://www.esfi.org/resource/aluminum-wiring-problems-and-repair-111
• The Spruce. "6 Tips for Handling Electrical Aluminum Wiring." https://www.thespruce.com/electrical-aluminum-wiring-repairs-1152832