Aluminum Wiring Facts and Fallacies

When first utilized in department circuit wiring, aluminum wire was not put in any otherwise than copper. As a result of elevated copper prices within the mid 1960’s, aluminum wiring grew to become extra prevalent in wiring installation properties. It was recognized on the time that aluminum wire requires bigger wire gauge than copper to hold the identical present.

For instance, a typical 15-amp circuit breaker wired with No. 14 gauge copper requires No. 12 gauge aluminum. Typical connections from electrical wire to electrical units, additionally referred to as terminals, are normally made by wrapping the wire across the screw terminals and tightening the wire or pushing the wire via the again of the outlet. Over time, many of those terminations to aluminum wire started to fail as a consequence of improper connection methods and dissimilar metals. These connection failures generated warmth beneath electrical load and resulted in overheated connections.

Historical past of Aluminum Wire

Electrical energy is transmitted from the utility producing stations to particular person meters utilizing nearly completely aluminum wiring. Within the U.S., utilities have used aluminum wire for over 100 years. It takes just one pound of aluminum to equal the present carrying capability of two kilos of copper. The light-weight conductors allow the utility to run transmission traces with half the variety of supporting buildings. The utility system is designed for aluminum conductors, and utility installers are conversant in set up methods for the kinds of aluminum conductors utilized in utility purposes. Previous to 1972, the aluminum wire was manufactured to evolve to 1350 sequence alloy. This alloy was particularly designed for energy transmission function. As a result of its mechanical properties the 1350 alloys weren’t appropriate to be used in department circuitry. At this juncture in time a “new expertise” of aluminum wire was developed, generally known as AA-8000 sequence which is the present aluminum wire used at the moment for department circuitry, nevertheless this can be very uncommon to search out in department circuit wiring. Such a wire when put in correctly may be simply as protected as copper wire.

Issues with Aluminum Wires

Aluminum wires have been implicated in home fires through which individuals have been killed. Stories of fires with aluminum wiring usually present that poor workmanship led to failures. Poorly made connections have been too usually the trigger. There have been a number of potential the explanation why these connections failed. The 2 core causes have been improper set up and the distinction between the coefficient of growth between aluminum wire and the termination used within the 1960’s.

Feeder and department circuit wiring techniques have been designed primarily for copper conductors. Aluminum wiring was evaluated and listed by Underwriters Laboratories for inside wiring purposes in 1946; nevertheless it was not used closely till 1965. At the moment copper shortages and excessive costs made the set up of aluminum department circuit conductors a really enticing various. On the identical time, metal screw grew to become extra widespread than brass screws on receptacles. As aluminum wire was put in extra ceaselessly, the trade found that modifications have been wanted to enhance the technique of connecting and terminating smaller aluminum wire. Set up strategies for utility grade aluminum, or sequence AA- 1350 alloy have been additionally completely different and workmanship was an necessary think about making dependable connections.

Probably the most usually recognized culprits for poor workmanship concerned: incorrectly tightened connections, wires wrapped the fallacious means across the binding screws, and aluminum conductors utilized in push-back connections or with units meant just for copper. As a result of the connections have been made incorrectly, a sequence of occasions of failures erupted. The connection was free to start with as a consequence of improper tightening torque, and the bodily properties of aluminum / metal interface tended to free the connection over time. Aluminum and metal have considerably completely different charges of growth which might improve the resistance and temperature on the termination level. Related issues occurred when aluminum conductors have been incorrectly terminated within the push-in connections meant just for copper wire.

Corrosion is usually cited as a contributing explanation for aluminum connections. In 1980 the Nationwide Bureau of Requirements carried out a examine to find out what brought about the excessive resistance at aluminum / metal connections in receptacles. The examine revealed that the formation of intermetallic compounds (alloys of aluminum and metal) brought about the excessive resistance terminations, not corrosion or aluminum oxide. The skinny, protecting layer of oxide on aluminum conductors contributes to the wonderful corrosion resistance of aluminum. When terminations are made accurately, the oxide layer is damaged through the termination course of permitting the mandatory contact to be made between the conducting surfaces.

Probably the most elementary ideas {of electrical} security for wiring buildings is that prime temperatures are hazardous. Warmth is a significant contributor to potential electrical hazards. A compromised connection creates extra warmth. The extra warmth contribution can “snowball” issues. Generally if adequate warmth is created, it could actually begin a fireplace. Even when the warmth doesn’t instantly begin a fireplace, the warmth can soften and or burn away insulation, which might create a brief which will arc. Electrical arcs usually attain temperatures in extra of 10,000 Fahrenheit. Aluminum wired connections in properties have been discovered to have a really excessive chance of overheating in comparison with copper wired connections.

Upgrading aluminum wired properties

There are a number of “upgrades” which can be generally completed to properties with pre-1974 aluminum department circuit wiring:

o Guaranteeing that each one units are rated to be used with aluminum wire. Many usually are not, since they don’t meet the CO/ALR specification

o “Pigtailing” which entails splicing a brief size of copper to the unique aluminum wire to be used with units not CO/ALR rated

o COPALUM a complicated crimping system that creates a chilly weld between copper and aluminum wire, and is regarded to be a everlasting, upkeep free restore. These connections are generally too giant to be put in in present enclosures. Floor enclosures or bigger enclosures could also be put in to treatment this drawback.

o Utterly rewiring the home with copper as a substitute.

When deciding to restore or substitute any electrical set up, a professional skilled needs to be consulted. The vast majority of properties wired with the overall function circuits wired with aluminum are actually over 30 years outdated. The probability of experiencing any issues distinctive to having aluminum is slight.

Any electrical system needs to be evaluated each 10 years by a professional electrical skilled to find out whether it is more likely to function safely beneath the elevated hundreds in several rooms getting used otherwise, i.e. dwelling workplace or loos with bigger dryers.

Alan Trauger is a Constructing Advisor that performs property situation assessments for residential and industrial properties. An skilled and educated drawback solver, understanding processes and points associated to constructing buildings and their techniques. An skilled witness, coach, and educator. To view previous newsletters on development and buildings

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