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Do You Have Aluminum Wiring In Your Home?

Electrical Aluminum Wiring and Your Home

On the off chance that your Hawaii home was constructed from the mid 1960’s to the early 70’s, you might be the lucky recipient of a home wired with aluminum conductors (wires). Because of the spike in copper costs during the 1960’s, wire manufacturers sought more affordable materials to use for electrical wiring, and aluminum appeared to be the best choice. Within a couple years, issues started developing with connection points and aluminum wiring.

copper vs aluminum wires
plantation style home on maui

 In the mid 1970’s, producers changed to copper clad aluminum which more closely resembled the quality of copper. However, by that point, the consumer view of aluminum wire was shot. Homeowners and tradesmen alike didn’t want to use it. While still permitted in most residential and commercial construction today, aluminum wiring has a different set of laws, code, and hardware requirements than copper wiring.

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Problematic Aluminum Wiring

According to the Consumer Product Safety Commission (CPSC), properties installed with aluminum conductors manufactured before 1972, are 55 times more likely to have faulty and fire hazard-deemed connections than a property wired with copper.

(Imagine if you were 55 times more likely to win the megabucks…)

Aluminum isn’t as effective at conducting electricity as copper is. This causes the wire to get hotter due to electrical resistance. Overheating aluminum conductors have caused home fires which is why homeowners were afraid of it and didn’t want it in their homes.

  • Higher Electrical Resistance
  • Expands & Contracts
  • Less Durable
  • Prone to Corrosion
  • Oxidation

Higher Electrical Resistance

Compared to copper conductors, aluminum wires give electricity a harder time to move. This is electrical resistance (super simplified). Heat from electrical resistance is similar to the heat caused by friction. It causes the electrical energy to be lost in the form of heat just like friction causes mechanical energy to be lost as heat.

Think of what happens if you rub your hands together. The harder you rub, the warmer it gets. While this is called “friction”, the principle is the same for the flow of electricity.

The heat from the electrical resistance melted the wire nut at this splice.

Expands & Contracts

Imagine this electrical arc but in your wall...

When electrical current flows through aluminum wires, the heat from the resistance that naturally occurs in aluminum wiring causes the wires to expand. This size change causes connections to become loose which is a major fire hazard. 

Wires that are not connected are separated by air. Air is NOT a good conductor, which means excessive heat and electrical arcing

Copper also expands and contracts but at a much smaller range. Due to it’s changing size, aluminum wires are never recommended to be installed with push-in/stab-in type outlets or switches. 

Poor Durability

In contrast with copper, aluminum is a fragile metal that doesn’t stand up to the twisting and bending which is what usually happens when installing electrical wiring. As it kinks, bends, or twist, damages to the metal create even more electrical resistance in the wire creating hot spots in the conductor. 

excessive electrical resistance in wire splice
Excessive twist in wirenuts damage the metal creating hotspots in the wire.

Corrosion Prone

corroded aluminum wiring
The aluminum ground wire corroded and no longer a viable ground.

Most metals experience the ill effects of a type of galvanic corrosion when they are connected to dissimilar metals. Include Hawaii’s salty, humid air and you’ve got trouble brewing. Since most outlets and switches are designed to be used with copper conductors, the greatest threat with aluminum wiring is unknowing tenants or previous homeowners replacing outlets and unknowingly connecting the homes aluminum wiring to the new device. This is probably the greatest cause for home electrical fires.


Every metal rusts, even aluminum. Copper rusts and turns green, however, that is alright in light of the fact that copper oxide (rust) has a low electrical resistance. Aluminum oxide has an exceptionally high electrical resistance, so it creates heat build-up and problematic connection points. A special compound must be used for aluminum wire terminations to prevent oxidation.

oxidation buildup on aluminum electrical wiring
Oxidation of the aluminum wire at the point of termination causes dangerous heat.

Solutions For Aluminum Wiring

  • Home Rewiring
  • Device Termination Types
  • Special Connectors for Aluminum Wires

Home Rewiring

While costly and invasive, whole home rewiring with copper wires will fix any and all issues caused by aluminum wiring. But before taking a sledge hammer to your drywall, there might be some better and more financially savvy choices to protect your home from aluminum wiring.

home wired with copper conductors
The most guaranteed solution for aluminum wiring in your home.

Device Connection Types

stab in vs wrap electrical connection type
Stab-in vs Wrap connection types

Like mentioned earlier, push-in or stab-in type connectors need to be avoided with aluminum wiring. Always use “CO/ALR” marked devices.  Stab-in devices are notorious for loose connections even with copper wires. 

Special Connectors for Aluminum Wires

Since the greatest issue with aluminum wiring is at its connection (termination) points, there are connectors specificly rated for aluminum wiring. Don’t simply go to Home Depot and grab any bag of wire nuts please! It must be marked specifically for use with aluminum wiring. If you’re unsure, ask a staff member to show you where the aluminum wiring specific connectors and devices are. 

Connectors, devices, and equipment marked with “Al/Cu” or “Cu/Al” are safe for aluminum wires. Be sure to double check and ask if you’re having an electrician do work on your home with aluminum wiring. 

wire nuts rated for aluminum connectors
Make sure you see the "Al/Cu" mark on any connectors you buy

But wait... there is a happy ending to this article

We’ve asked number old timer Maui electricians who’ve been working on Maui for their whole career exactly how many homes they’ve encountered with aluminum wiring. You’ll be pleased to hear the highest answer we got was “2”. 

Out of a combined 100 years of electrical experience, only 2 known homes on Maui are known to have aluminum wiring. The chances of your home being at risk for this type of wiring is extremely low. 

But if we’ve scared you, we apologize. Our experienced electricians will be happy to take a quick look at your electrical panel a some devices around your home to make sure you aren’t at risk.

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