ALUMINUM GENERAL LIGHTING CIRCUITS

C.  ALUMINUM GENERAL LIGHTING CIRCUITS:

SPECIAL NOTE: The information below is controversial and has political elements to it.  Many fire departments, code enforcement officials, and professional home inspectors take issue with it.

There are three classifications of wiring circuits within residences: major appliance circuits, minor appliance circuits, and general lighting circuits.  General lighting circuits are of critical concern if they utilize aluminum conductors (Fig. C1, Item A).  Many tract houses built between 1964 and 1975 utilized this type of wiring and are considered (by the U.S. Consumer Products Safety Commission) a significantly higher fire risk than similar houses wired with copper for these single strand circuits.

Fig. C1

Government sponsored research has indicated that aluminum wire heats up and expands more than copper wire. Aluminum wire also appears to have a chemical reaction where it contacts the metal of securing pieces of some receptacles and switches.  A combination of these and other factors may cause poor connections and allow aluminum oxide to form on the wires at the connection point.  Aluminum oxide is highly resistive to electric current flow.  A connection point, that is highly resistive, will heat up as electric current passes through it.  This will create an intermittently hot connection situation. According to the government research, it is estimated that one in every five houses with aluminum wire in the general lighting circuits, has one intermittent hot connection.

The National Electric Code is relatively silent on this issue. Over the years, while investigating complaints, the repair procedures recommended by the Consumer Product Safety Commission have changed. At present, there is no specific recommendation for dealing with the larger multi-strand aluminum “service entrance cable” (Fig. C1, Item B) and major appliance circuits typically found in most homes (Fig. C1, Item C).  NOTE: Some professional electricians specializing in aluminum wire repair feel that there is more of a problem with the multi strand wiring than the single strand wiring.

Popping, snapping, or heat from receptacles, fixtures, or switches is a warning.  All connections are to be made in approved electrical junction boxes.  Amateur repairs to aluminum wire systems are considered ultra high risk.  Insurance rates are generally not affected by the presence of aluminum wire. However, recent trends show that in some States it is difficult to obtain Homeowners Insurance if aluminum branch wiring is present in the house and the insurance that is available is at a higher premium.

CANADIAN DIFFERENCES:
The AMP cop/alum connector method is not generally available throughout Canada.  In Canada, an aluminum system is considered safe, provided good workmanship exists. The receptacles should be labeled as either “CU-AL” or “CO ALR”.  If not so labeled, the receptacles should be pigtailed to the aluminum conductors with “AL CU” marrets (connectors with silver inside).  A 3/4 wrap should be made around the receptacle screws.

WARNING:  Aluminum wire used with push in type receptacles is considered hazardous. A home inspector will not remove receptacles, and thus will not be able to make this determination.

WHAT TO:   HOW TO:
According to the U.S.C.P.S.C. the safest way to repair aluminum general lighting circuits is to have a professional use the AMP Special Industries “COP ALUM” connection method.  The work should be done by an electrician that specializes in aluminum wiring repair.  Aluminum repair work is NOT COVERED BY THE NATIONAL ELECTRICAL CODE, hence most PROFESSIONAL ELECTRICIANS MAY NOT KNOW THESE PROCEDURES.  These repairs involve installing special connecting devices between the original aluminum wires and new short sections of copper wires.  The old and new wires are attached by crushing the connecting devices around them with a pneumatic crusher.  The now extended wires are then reconnected to the existing receptacles.

This process is relatively expensive ($18.00 and up (depending on competition) per opening and $200.00 and up for the main panel) and must be very carefully done.  Older aluminum wires are often somewhat brittle and easily break off inside walls, etc.  This method is a less expensive repair than rewiring an entire house, and once this is done, the repaired system is considered safe.  Other methods of upgrading safety have been developed, but none approach this high standard.  The Consumer Products Safety Commission recommends no other method.

Special “warning” screws were once available that changed color when they heated up. These can be used to attach cover plates over receptacles wired with aluminum.  They may give a warning that an intermittent hot connection exists.

REFERENCE: E7, E8