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Top Five Failed Building Practices: Part 1 of 5 Aluminum Branch Wiring


Here is the first installment of the five-part series, The Top five Failed Building Practices:

The good old days weren't always so great for home construction. Some products have become standards, like copper electrical wire, asphalt roof shingles and poured concrete foundations. But others that were once widely used have proven to be much less successful, and sometimes hazardous.

Here are what many in the industry consider the top five failed building practices:


Here is the first installment of the five-part series, The Top five Failed Building Practices:

The good old days weren't always so great for home construction. Some products have become standards, like copper electrical wire, asphalt roof shingles and poured concrete foundations. But others that were once widely used have proven to be much less successful, and sometimes hazardous.

Here are what many in the industry consider the top five failed building practices:

  • Aluminum Branch Wiring
  • Fire-retardant treated plywood
  • Polybutylene pipes
  • Federal Pacific "Stab-Lok" electrical panels
  • Asbestos insulation. 

Builders don't use most of these products anymore, but because they were popular in their day, they exist in tens of thousands of houses around the country.

As a home inspector, I see them all the time. For safety reasons, homeowners and home buyers should know about them, too.

If a house you plan to buy has one or more of the items on this list, could that be enough to kill the deal? Probably not, but all things must be considered, including the cost to correct. Knowing what you are buying and what you may be faced with down the road could help you make the right choice in a home purchase.

Part 1: Aluminum Branch Wiring

Aluminum WiringMany houses built between 1964 and 1976 have aluminum branch circuit wiring. (Branch circuits are the wires that run to each room from the service panel.) This product was developed because copper became expensive and hard to get during the Vietnam War.

Aluminum is the third-best conductor of electricity, behind copper and gold. It was an easy alternative to copper wire.

However, this wiring turned out to be a fire hazard. The connections between the wire and a light switch or outlet can arc, causing a spark that can burn the connection point; fire can spread from there.
There are repairs that all but erase the threat of a fire. The Consumer Product Safety Commission (CPSC) recommends either that the aluminum wire be replaced with copper or that the connections be repaired using specific methods.

Repair is less expensive than replacement, although it can still cost thousands of dollars in a standard-size house. Every connection between the aluminum wire and an outlet or light switch needs to be retrofitted using a piece of copper wire and a connector.

The CPSC has approved only one retrofit technique, called a COPALUM connector, used with a special crimping tool.  However, in practice, many more of these systems seem to have been retrofitted with a product called the Ideal Twister Al/Cu (aluminum-copper) connector, a purple wire nut filled with a non-oxidizing compound. The Twister complies with the National Electrical Code and has been Underwriters Laboratories-listed. These repairs are less expensive than COPALUM repairs.

However, the CPSC does not approve that fix, agency spokesman Scott Wolfson said. "We know that there are those in the electrical safety community who disagree with us, but we remain firm in our position."

He said that except for COPALUM, there is no other retrofit on the market "that CPSC's electrical engineers can say with confidence provides a long-term fix." The agency remains concerned that other repairs could oxidize at the connectors over time, leading to electrical fires behind drywall, he said.

All work on aluminum wiring should be done by licensed or certified electricians. Improperly repaired wiring is a fire hazard. Aluminum wiring is most easily identified at the main electrical panel by a trained professional.

Look out for parts 2-5 of this 5-part series!