7/31/2019 Vol8no2 Aluminum Wiring

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The Newsletter of Investigative Engineering Volume 8 N

A Publication of the Investigative Engineers Association, Inc. (I-ENG-Nationwide (800) 523-3680 www.ienga

Aluminum wiring was commonly used from about1965 until about 1977 as an alternative to copperwiring. Aluminum (Al) was considerably lessexpensive than copper (Cu). Most homes builtduring this time frame have aluminum wiring.

According to the US Consumer ProductSafety Commission (CPSC), homes installed

with aluminum branch circuits (manufacturedbefore 1972) are 55 times more likely to haveone or more connections reach Fire HazardConditions than a home wired with copper.

Many building codes have been rewritten to notallow the use of aluminum wire for branch circuitwiring in houses.

The Problem

The problem arose because the industry did notunderstand the fact that the coefficient of

expansion of copper is different than that ofaluminum. That is, as electrical circuits areturned on and off, the wire heats up and coolsdown. This thermal cycling causes the wire toexpand and contract at a rate different thanadjoining copper connections. If these becomeloose, arcing can occur at these points.

Other concerns with aluminum wire:

- Aluminum does not conduct electricity as well ascopper and generates more heat. Thisoverheating can cause fires.

- Aluminum is more brittle than copper and is more

likely to break or crimp. Arcing can occur if a wirebreaks or crimps, causing very high temperaturesinside the wall or ceiling.

- Aluminum is more likely to corrode (i.e., oxidize) thancopper. When excessive corrosion occurs itincreases the resistance in the circuit and causesoverheating. A thinner wire creates more heatwhen electrical current is running through it.

- Oxidation also causes the wire to expand,puttingpressure on the wires protective plastic coating,causing the plastic to split. If any of these occur,arcing may result which can cause fires.

Possible Concerns with Aluminum Wiring

Therefore, it is very important that electrconnections be made using similar materialsthat the connection does not loosen and cauoverheating and/or sparking. There approved mechanical connectors that can used as well, that take into account tphenomenon.

How do you know if you have aluminumwiring?

Most known problems are associated with saluminum wire, sizes #10AWG, #12AWG, a#14AWG. The wiring will be located between distribution panels, outlets and light switchessingle-phase 120V services. When the buildwas originally constructed, devices and switcwith older CU/AL marking should have beinstalled. Unless every device and switchremoved from its box and looked at, there canno assurance the installing contractor actu

used the more expensive aluminum radevices. Likewise, over the years, residemay have replaced devices with the cheapcopper-only rated units, not knowing there special requirements for these devices.

There are several warning signs to look for thawould suggest possible connection problems:

- Sparks, smoke, or the smell of burning plastiemanating from outlets

- Outlets and Switches that are warm to thetouch

- Lights that flicker, shine unusually bright or bout quickly

- Blown fuses or breakers that trip for noapparent reason

What can I do if I have aluminum wiring?

Aluminum wiring can be just as safe as copwhen properly installed. The National ElecCode is very explicit on the use of devices aaluminum wiring (Refer to section 110-14[b]connections, 380-14[c] for snap switches, a410-56[b] for receptacles).

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7/31/2019 Vol8no2 Aluminum Wiring

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THE NEWSLETTER OF INVESTIGATIVE ENGINEERING

Possible Concerns with Aluminum Wiring

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There are two (2) available options that can beemployed that would maintain the integrity of theexisting electrical system with regards toreceptacles and snap switches:

Option 1: Purchase and install new CU/ALRdual rated receptacles and snap switches in allunits where devices are found without aCO/ALR or CU/AL marking. See NEC Article380-14(c) and 410-56(b). This serves to ensurethat every device will be the proper one for

aluminum wiring. It also weeds-out any looseconnections and any devices that have beenreplaced with the copper only units.

Option 2: Each device should be pulled from itsbox and checked for loose connections,discoloration, and rating. If a device is foundwithout the CO/ARL dual rating marking, theycan be replaced with the proper rated device, orthe existing device can be reused if a UL listed

AL/CU rated twist-on connector is spliced as acopper pigtail between the device and thealuminum wiring. As an alternate, a crimp-on

splice connector with heat shrink overall sleevecould be used to connect the pigtail to thealuminum but the labor costs are higher.

It is important to be aware that on futurereplacements, all receptacles and snap switchesmust be purchased with the CO/ALR markingon them. This is the NEC acceptable devicedesigned to be used on aluminum conductors.

Final Note

If contemplating buying an older building withaluminum wiring or updating a building withaluminum wiring, contact a certified electricianto gain their expertise and opinion regardingthe dangers of aluminum wiring.

If at any time you suspect your electricalsystem as the source of smoke or unusualheat, do not hesitate to call your local Fire

Department. There is never a charge for thisservice. The safety of your family, employees,and property should be your primary concern.

References:

Aluminum Wiring Hazards web site,http://www.inspect-ny.com/aluminum.htm

Aluminum Electrical Wiring, Report promulgated byCity and County of Denver, January 11, 2001,

http://www.denvergov.org/admin/template3/forms/Aluminum%20Wiring,PDF

Article originally published by:

Professional Investigative Engineers,Investigative Engineers Association, Inc.

(I-ENG-A ) Member, Coloradowww.callpie.com

I-ENG-A Member Firm Profile located athttp://www.ienga.net/pie.htm

Copyright 2004 Investigative Engineers Association, Inc., All rights reserved.

VOLUME 8 NO. 2