Aluminum wiring in residential homes…

Aluminum wiring was used in residential homes primarily between 1965 to 1976. The wire is safe…it’s the connections that cause the problem. What happens is, because of the molecular properties of metal, when electricity passes through aluminum it heats up and expands. When the flow of electricity stops, it contracts and resumes it’s normal ambient temperature. This expansion and contraction can cause a loosening of the connection between the wire and the breaker or receptacle. Under load, once this connection is loose it starts to arc. The higher the electrical current of the device the more severe this problem may become. This problem is called “Cold flow”.

 

I remember being called to a residence here in Edmonton to investigate a problem with a power outage. I checked the panel and determined that there was aluminum wiring installed throughout the house. The master bedroom, half bath, second bedroom, and hallway were not working. The problem ended up being that the wall receptacle in the half bath was used primarily for hair dryers and curling irons. This was the first point in the circuit coming from the panel.

 

I opened the box and gently pulled out the receptacle. As I did, the sound of sizzling and a bright blue light filled the bathroom. When I finally got the receptacle fully extended to the end of the wires, I noticed that the only thing left was the plastic front face and the metal contacts of the plug. The remainder of the receptacle was in a puddle of plastic in the bottom of the box. “Cold Flow” had loosened the connection between the screw and the wire. With the high current draw from the hair dryer and curling iron the arcing had totally destroyed the bathroom receptacle. This is what was determined to be the cause of many fires in the past and that made aluminum wiring for residential construction a thing of the past.

 

Today, we have an acceptable method of solving this problem. We remove the original receptacle and switches, usually rated for Aluminum, and replace them with new devices, rated for Copper. We then pigtail (put two together under a wire connector or Marrett) the aluminum to a copper wire. This copper wire now gets put on to the new receptacle or switch and reinstalled. Copper and aluminum together will oxidize, so to prevent this problem we cover the aluminum wiring with a retail product that prevents oxidization. By doing this we have eliminated the problem of cold flow.

 

For answers to questions or free estimates for conversions please call and see our web site at:

Your residential service upgrade professionals 

www.robartelectric.com 

Rob Swyrd

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How can you tell if you have a 100 amp residential service?

    Before 1960, residential service were normally 60 amp. These panels were normally located  by the back door of homes usually above the stairs going up to the main floor or behind the inside door.

 To be a 100 amp service, it must first of all have a main breaker that has “100” written on the handle. This is a large breaker located at the

top of the panel above the 2 vertical rows of smaller breakers. In homes built between about 1960 and 1968 you will usually find a larger than normal breaker at the top of the panel (main breaker) but the rating on the breaker was normally 60 or 70 amps, these still require upgrading.

There is a very simple list of requirements for converting older homes to a 100 amp service. Service conversions range from roughly $775.00 to about $2600.00 for the more difficult conversions, and are always completed the same day with very little disruption to home power. Last year (2011) we
did over 50 conversions.

When acquiring a home, the buyers need to be aware of the fact that now, most insurance companies are not giving home insurance on a purchase until the main service has been upgraded. Also, some mortgage companies are refusing mortgages if the service is not 100 amps.

If you have any questions about determining if you have a 100 amp service or not please call me at 780 238-8195

Rob Swyrd Director of Robart Electrical Services Ltd.