Human beings always are looking to substitute new, less-expensive versions of successful products that have been tried and true for years. Sometimes this works well (a cheap, hand-held hair dryer versus a full-size, hair salon, sit-in-the-chair-and-put-your-headinside hair dryer); sometimes it doesn’t (Yugos and Vegas versus most other automobiles). In the electrical world, the use of aluminum wire for running branch circuits falls into the latter category of substitutes gone bad.
Aluminum wire was installed in at least 1.5 million homes between 1965 and 1973. The material cost was as little as 50 percent of the price of copper wire, which made it a hit with home builders, even if it ended up being a false bargain for home buyers. Unforeseen problems with the connections of the wire to devices lead to it being labeled a potential fire hazard and ultimately banned from most residential use. Although I could find no figures as to the actual number of homes that burned down due to electrical fires from aluminum wiring, there were enough to initiate studies, accusations, lawsuits, and not-so-veiled warnings regarding its use. The problem wasn’t immediately apparent because aluminum-wired circuits can take years to reach a failure point while still remaining functional.
Is aluminum wiring a red flag in your house-purchasing adventure? Yes, but there are ways to deal with it intelligently.
number of view: 2
Tags: 1963 and 1973, banned, cheap, home builders, home buyers, homebuilders, lawsuits, less-expensive, material cost
Electric Repairs, Home Remodeling | TeamAbsolute6 April 28, 2009 | 
Comments (0)
According to the U.S. Consumer Product Safety Commission (CPSC), problems with aluminum wiring manufactured prior to 1972 include …
• Expansion and contraction of wires.
• Easily damaged during installation, because it’s a soft metal.
• Corrosion.
Aluminum wiring heats up more easily than copper wire from electrical currents passing through it because it has a higher resistance. As a result, aluminum wire must be one gauge size larger for a given circuit than if copper were used. Thus, a 15-amp circuit could use No.14 copper wire but would require No.12 aluminum. As a conductor, aluminum heats up when a current passes through it. Like any heated wire, it expands and contracts as it heats and cools, but aluminum is damaged more than copper by this cycle of temperature changes.
Adding to this problem are the connections (or terminations) at devices and fixtures. Aluminum tends to oxidize when it comes in contact with some other types of metals—the same ones that often compose the termination material (such as brass terminal screws). Now we’ve got a metal that’s already touchy about heating and cooling, and it’s also corroding and offering even more resistance to the current. The corrosion adds to aluminum’s natural resistance, making that resistance even worse.
As a result …
• The connections deteriorate and loosen at the terminals.
• There is arcing or a discharge of electricity across the gap between the end of the wire and the terminal.
• There is possibly enough heat to melt the insulation and cause a fire. Aluminum wiring can easily be damaged because it’s so soft. If a piece gets nicked while the insulation is being stripped during installation, the nicked area is weakened and can deteriorate faster than the rest of the wire as it heats up. So much for that 50 percent savings in material cost when this stuff was installed!
number of view: 8
Tags: (CPSC), 1972, aluminum heats up, aluminum wiring manufactured, contacts, devices, fixtures, oxidize, soft metal, terminations, U.S. Consumer Product Safety Commision, weakened wire, wire deteriorated, wire nicked
Electric Repairs, Home Remodeling | TeamAbsolute6 |
Comments (0)
Aluminum wiring primarily affects housing built from 1965 to 1973, but it also can be present in additions and remodeled sections of older homes if the work was done during these years. The first thing to look for during your snooping is the word “aluminum” printed or embossed on the plastic sheathing of the electrical cable. If the cable isn’t observable in an attic space or a basement ceiling, look in the service panel. Remove the cover plates and look at individual switches and receptacles to see whether the wire ends are copper- or silver-colored.
number of view: 13
Tags: 1965 to 1973, aluminum, attic, basement, ceiling, cover plates, electrical cable, houses built, individual switches, plastic sheathing, service panel, silver color
Electric Repairs, Home Remodeling | TeamAbsolute6 |
Comments (0)
Not every house with aluminum wiring is an automatic time bomb waiting to burst into flames like a vampire caught outside at dawn. The warning signs used to check for overheating problems and loose connections include …
• Warm cover plates.
• Flickering lights.
• No power in a circuit.
• Sparks and arcing.
These are signs and suggest turning the power off and examining individual devices and loads with a flashlight for the following:
• Charred or discolored plastic
• Back-wired devices
• Excessive tarnishing at the ends of the wires
• Damage to the thermoplastic sheathing including melting and bubbling Some wiring might not show any signs of deterioration because a particular circuit might never have had enough loads on it to cause overheating. If you plug a portable heater in, however, the status quo might change rapidly. The best defense is to monitor these circuits if their usage changes.
Any of these defects is cause for action. Are they enough of a reason for you to walk away from a potential property purchase? No, because even though technology caused the problems, it also can resolve them.
number of view: 1
Tags: arcing, back wired, charred, cover plates, deterioration, discolored, discolored plastic, flickering lights, melted sheathing, no power, sparks, tarnishing ends, thermoplastic, warm cover plates
Electric Repairs, Home Remodeling | TeamAbsolute6 |
Comments (0)