During the mid-1960s and mid-1970s during the Vietnam War copper prices were at a then-all-time high, making it expensive to put into homes for electrical wiring. Although nowhere near the cost it is today, copper at the time was difficult to mine and process, and it was being purchased in mass quantity for military purposes.
Aluminum wiring seemed to be exactly what the home-building industry wanted at the time, a cost-effective alternative to copper wiring when installing correctly. Approved by Underwriters Laboratories as far back as 1945 for interior wiring, there were still some issues that needed to be worked out if aluminum wiring was to be an industry standard.
Aluminum Wiring Issues
Firstly, because aluminum wiring was so much softer than copper it couldn’t withstand the same stress when being pulled. It was also more at risk of being broken. Still, it was a much cheaper alternative at the time that actually was a sound choice if installed properly. In turn, homebuilders began to use 12 AWG and 10 AWG type NM-C sheathed cables in massive amounts, and local building inspectors were in short supply. In addition, they probably knew even less at the time than electrical contractors did about aluminum wire installation.
While there is widespread concern about aluminum wiring in homes, it’s not actually the material itself that is at issue. In fact, aluminum is used on larger circuits to this day, those that don’t terminate as often to various devices. Many electricians still use aluminum for feeders and large appliances; engineers still call for aluminum on large feeders and branch circuits. These circuits are terminated suitably in disconnects and electrical panels with lugs.
Commonly, aluminum is no longer used on smaller circuits because of the termination issues. Aluminum must be terminated with compatible devices like crimp sleeves, lugs and screw terminals. In addition, the wiring must be treated with an oxide inhibitor. Herein lies the problem; homes built with aluminum wiring at this time were not installed with the correct devices for termination and an oxide inhibitor wasn’t used. Using Co/Alr-type devices, which are receptacles and switches that are rated for aluminum and copper, would have resolved many of the issues that have surfaced. Instead, because of the composition of terminals and screws that were used, incompatibility issues arose, with the metals causing oxidation that warped the devices. This is because aluminum’s expansion and contraction rate is different from copper’s.
Aluminum Wiring Today
To this day there are many subdivisions that carry aluminum wiring that wasn’t installed with Co/Alr devices. You may remember Geraldo Riveria’s 60 Minutes special on aluminum wiring fires and the feeding frenzy of insurance companies looking for homes with improperly installed aluminum. These days, decades after the homes were wired, many insurance companies won’t even insure homes with aluminum wiring. Others make you take additional steps to ensure the safety of your home and raise your premium.
While there are some workarounds for the risks that aluminum wiring pose, you may run into some issues with your home insurance carrier. There are three common options, pig-tailing (adding a short piece of copper wiring to the aluminum wiring), replacing all devices with Co/Alr -friendly devices, or rewiring the entire home (by far the most drastic option). The final option, the most difficult and complicated option, is being pushed for heavily by insurance companies. Here are come considerations with the three options:
Here are some considerations with the three options:
- When pig-tailing, you will need to use a special (and expensive) wiring nut that contains an oxide inhibitor.
- It’s equally expensive to replace all of your switches and receptacles with those that are Co/Alr-friendly.
- Completely rewiring the roof carries many complications, including high-pitched roofs and horizontal fire bracing (common in older, ranch-style homes) and how contractors must price the job (it’s often hard to estimate with so many variables).
Aluminum wasn’t the culprit, but rather how the wiring was installed. As an aside, while you should always have smoke alarms when you live in a home with aluminum wiring, it’s especially critical. If you are considering purchasing a home with aluminum wiring, we recommend that you call your insurance company to get their thoughts before you complete the purchase.
Got questions about aluminum wiring? Feel free to reach out to us at Gulf Coast Electric today about specialty wiring!