Introduction
Aluminum wiring became popular in American homes during the 1960s and 70s as copper prices were rising. However, aluminum has some important differences from copper that make it more difficult to work with safely. Improper connections and faulty terminations can lead to dangerous overheating and fires.
As a homeowner, it's important to understand the risks of aluminum wiring and how to mitigate them. With proper precautions, aluminum wiring can be used safely in your home. In this guide, I'll cover everything you need to know, including:
- The risks of aluminum wiring and how it differs from copper
- Warning signs of unsafe aluminum wiring
- Best practices for connections and terminations
- When to call an electrician
- Re-wiring and remediation options
- Working safely with outlets, switches and fixtures
Follow these safety guidelines when working with aluminum wiring and you can help protect your home and family.
The Risks of Aluminum Wiring
Before the 1970s, most residential wiring in the US used copper. Copper is highly conductive, flexible and has stable contact properties. However, copper prices increased dramatically in the 60s, leading builders to switch to cheaper aluminum wiring.
Aluminum has some important limitations compared to copper:
- Aluminum has only 61% of the conductivity of copper. More amps can lead to overheating of connections.
- Aluminum expands and contracts more with temperature changes, leading to loosening of connections over time.
- Aluminum corrodes more easily than copper when exposed to air. Corrosion can increase resistance.
- Aluminum is more difficult to properly terminate, requiring special techniques and materials to make tight, non-loosening connections.
These factors can lead to dangerous overheating and arcing faults if the wiring is not maintained properly.
Warning Signs of Unsafe Aluminum Wiring
As an aluminum wired home ages, problems can develop if the wiring was not properly installed initially or has deteriorated over time. Here are some warning signs to look out for:
- Flickering lights or intermittent power to devices. This can indicate a loose or corroded connection that is heating up.
- Frequently tripped circuit breakers. When a circuit overheats, the breaker will trip to cut power. Frequent tripping indicates an underlying issue.
- Discolored, warm or melted outlets or switches. Heat damage indicates connections are failing.
- Buzzing from switches or outlets. This noise comes from arcing as connections corrode.
- Burning or electrical smell from fixtures or outlets. Overheating connections emit a distinctive burning odor.
Any of these warning signs indicate you should have an electrician inspect the aluminum wiring for safety. Left unchecked, failing connections can overheat and start fires.
Best Practices for Safe Connections
Proper installation and maintenance is crucial for safely using aluminum wiring in your home. Here are the key best practices to follow:
Use CO/ALR Rated Switches, Outlets and Connectors
- CO/ALR labeled devices are engineered for use with aluminum wiring. Normal copper-only devices can be unsafe.
- ALR outlets and switches have set-screws designed to tighten properly on aluminum and resist loosening over time.
- CO/ALR labeled wire nuts and connectors are required for joining copper to aluminum wires.
Use Anti-Oxidant Paste on Connections
- Aluminum oxidizes when exposed to air, increasing resistance. Anti-oxidant paste counteracts this effect.
- The paste helps produce tighter, more conductive connections that resist loosening.
- Apply paste to all connections during installation and maintenance. Wipe away excess.
Ensure Tight Connections with Proper Torque
- Under-tightened connections cause overheating and arcing. Proper torque ensures tight connections.
- Use a calibrated torque screwdriver during installation and maintenance. Tighten screws on devices to spec.
- For wire nuts, tighten firmly by hand and then an additional quarter turn. Do not over-tighten.
Avoid Back-Stab Connections
- Back-stabbing wires into the back of outlets does not provide a secure termination for aluminum. The spring tension can loosen over time.
- Wrap wires clockwise around side screw terminals, with proper torque. This provides a tight, safe connection.
By following these best practices whenever working with your home's aluminum wiring, you can mitigate the risks and have added peace of mind.
When to Call an Electrician
While DIY-inclined homeowners can safely perform basic aluminum wiring jobs with proper precautions, more complex tasks should be left to licensed electricians. Call a professional for:
- Evaluating your home's original aluminum wiring installation. They can check for any red flags.
- Comprehensive inspections if you suspect you have unsafe wiring based on warning signs.
- Major appliance or HVAC system installations or upgrades. Large loads require expertise.
- Whole house rewiring if recommended after inspection. This is not a DIY job.
- Adding new circuits, outlets or switches. This involves working at the main service panel.
- Any work you do not feel comfortable attempting as a homeowner. Safety first.
Though it may cost more upfront, having electrical experts handle tricky aluminum wiring jobs is worth the added peace of mind and safety.
Re-Wiring and Remediation Options
If your home's existing aluminum wiring is found to be unsafe by an inspector, there are a few options to fix the issues:
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Individual circuit repairs: Electricians can replace any damaged wire runs and problem connections. This targeted approach fixes issues without rewiring the whole home.
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CO/ALR repairs: Swapping out standard outlets and switches for CO/ALR rated ones can make existing wiring safer. The ALR switches provide a compatible termination.
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Full rewiring: For severely damaged wiring, or as a preventative measure, rewiring the entire home with copper is the ultimate solution. This is a major undertaking though.
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Aluminum wiring pigtailing: Individual length of copper wire are connected to aluminum wires at outlets and switches. This adds compatible copper ends.
Consult with qualified electricians to determine which remedy is right for your situation.
Working Safely with Outlets, Switches and Fixtures
With vigilance and proper technique, DIY-ers can safely perform basic aluminum wiring jobs like installing or replacing outlets, switches and light fixtures:
Gather Compatible Materials
- Purchase CO/ALR rated outlets and switches when possible. Alternatively, use copper pigtails.
- Use only connectors and wire nuts listed for CO/ALR use.
- Have anti-oxidant paste on hand for all connections.
Prep the Wires
- Flip the circuit breaker off and verify power is cut with a tester.
- Carefully disconnect the existing wires from the current device.
- Thoroughly clean the ends of the wires with wire brush or sandpaper to expose shiny metal.
Make New Connections
- Apply anti-oxidant paste liberally to all wire ends.
- Securely fasten wires under the screws of the new device.
- Follow torque specs when tightening screws.
- For wire nuts, ensure the connection is very tight.
Other Precautions
- Never install aluminum wires into the back-stab connections of outlets or switches. Use screw terminals only.
- Check that all junction boxes are large enough for the number of wires inside.
- Label any switch, outlet or other connection that has aluminum wiring.
By using the proper materials and techniques, you can safely DIY simple aluminum wiring jobs. But know when to call a pro too!
In Conclusion
While aluminum wiring can seem like a hazard, it can be used safely in homes with proper installation and maintenance. The risks come primarily from improper connections that overheat. By using CO/ALR rated devices, anti-oxidant paste, proper torque levels, and avoiding back-stabs, you can mitigate these risks. Pay attention to warning signs of issues like flickering lights. More complex projects should be left to qualified electricians. With vigilance and care, aluminum wiring can provide safe and reliable electrical power to your home.