Aluminum Wiring Q&A

QUESTION

“We just inherited a 45-year old house, and shortly after we moved in we noticed that the lights would occasionally flicker on and off. Some switches were hot to the touch. I contacted an electrician to come over and inspect the wiring. He said that the problem was with the aluminum wiring used in my house. He showed me burn marks at some switches and outlets. He said that I should have the whole house rewired and that can cost thousands of dollars. My parents were the original owners, and I don’t remember them ever having a problem. How much of a concern is it to have aluminum wiring in the house?” –  D.S., San Mateo

ANSWER

Aluminum wiring has been used for many years in residential construction and is still being used today. Properly installed, it is as safe as copper wiring. In fact, you will probably find it (to some extent) in more than 90% of the homes, condominiums and apartments being built today.

The fears and concerns about using aluminum wiring usually dates back to the late 1960’s, because aluminum wiring got a lot of bad press. There were several cases where electrical fires had been occurring in houses built with aluminum wiring. In some homes, people would have switches and outlets getting hot when in use, and sometimes causing shocks to individuals, or starting fires.

Before the 1960’s, most homes in California were wired with copper wire. It was cheap and easy to work with. Then in the early 1960’s the price of copper had gone way up, and contractors building large housing tracts turned to using aluminum wiring as an alternative. PG&E had been using aluminum wiring for years and never had any problems.

What the contractors did not understand at the time, is that the characteristics of aluminum wiring are very different from that of copper, and that there were specific installation standards that had to be followed when using it. Investigations that followed all of these fires were able to prove that it was not the wiring that was the source of the fires, but rather the workmanship of how the wiring was installed.

Aluminum wiring is soft, has a low melting temperature, expands when heated and oxidizes easily. Because of this, aluminum requires that any connection to it be made in such a way that the wiring will not be able to loosen. This is usually done with a special crimping tool and special connectors. Copper wire on the other hand, is a little more stable and flexible than aluminum wiring, and does not require the special connectors

The secrete to living with, and using aluminum wiring, is making sure that it is properly installed with the proper connections. The National Electrical Code requires that any fitting connected to aluminum wiring be approved for use with that type of wiring. This basically means that you cannot connect an outlet, switch, fixture or fitting to aluminum wiring unless it is rated to be connected with aluminum wiring. These devices should be clearly marked with the designation “CU/AL” or “CU/ALR”. This means that the fitting is approved for use for copper (CU) and aluminum (AL). The “ALR” designation means aluminum residential.

What happened back in the 1960’s is that the installing contractors were connecting the aluminum wiring to outlets, fixtures and switches that were designed to be connected to only copper wiring. The fact that your house has aluminum wiring should not pose a safety problem if it is properly installed.

Your question seems to indicate that the problem with the wiring is at the joints or connections to the switches and outlets. This is where most of the problems occur with aluminum wiring. Because aluminum wiring expands and contracts a bit when an electrical load is running through it, it tends to heat up and loosen connections if it is not properly tightened. This usually results in a switch or an outlet being warm or hot when touched. Over the years, this overheating tends to damage outlets and switches. Merely replacing these devices will fix the problem in most cases.

To ensure the safety of your electrical system, you should have it inspected by a qualified electrician. Start by having the electrician inspect all your outlets and switches. It is possible that there is a loose connection at some other area, such as a light fixture, junction box, or sub panel. In any case, a good electrician should be able to trace down all of the problems.

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