How To Identify Aluminum Wiring

How To Identify Aluminum Wiring

There are problems associated with this wiring due to its brittleness, expansion properties, oxidation
issues, and deformity when under stress, known and cold flow.
Because of these problems, the connections can become loose, causing electrical arc and ignition of
nearby combustibles which may lead to fires. The Commission has also conducted research that
shows that buildings wired with aluminum wire manufactured before 1972 (“old technology” aluminum
wire) are 55 times more likely to have one or more connections reach “fire hazard conditions” than a
building wired with copper.

A fundamental principle of electrical safety for wiring in buildings is that high temperatures are
hazardous. While some protection is provided by electrical enclosures, high temperatures can develop
at failing branch circuit connections can lead to fire in many ways. Aluminum-wired connections have
been found to have a very high probability of overheating compared with copper-wired connections.
The aluminum-wired connections that fail tend to progressively deteriorate at a slow rate, and after
many years can reach very high temperature while still remaining electrically functional in the circuits.
A large number of connection burnouts have occurred in aluminum-wired buildings.

How To Identify Aluminum Wiring?

Virtually all of the aluminum wiring was
installed as plastic-sheathed cable (type
NM, often called “Romex”) with no readily
discernable distinction from a cable with
copper conductors. Look at the printed
or embossed markings on the outer jacket
of the electric cables, which are visible in
unfinished basements, attics, or garages.
If necessary, use a flashlight shining on
the surface at a low angle to help make
the embossed markings readable. Cable
with aluminum conductors will have “Al”

or “Aluminum” and other information
marked on one side of the cable jacket
every few feet along its length. (Note: be
sure to read as much of the marking as
possible because the marking “CU-clad”
or “Copper-clad,” in addition to the “Al”
or “Aluminum,” means that the cable uses
copper-coated aluminum wire and is not
covered by the repair recommendations
outlined in this article.

Aluminum and copper-clad aluminum cables are sized at No.10 and No.12 AWG for 20-ampere and 15-ampere rated circuits, respectively, as opposed to No.12 and No.14 AWG for copper conductors.

The repairs outlined in this article do not apply to larger gauge aluminum wire circuits and connections used for service entrance cables, electric clothes dryers, and cooking ranges.

If you are unable to identify the type of
wire in your home by this method, but
you suspect that you have aluminum
wire, have a qualified electrician make the

What Does Aluminum Wiring Look Like?

Aluminum Wiring Remediation

Aluminum wiring can be replaced or
repaired to effectively and permanently reduce the possibility of fire and injury due to
failing (overheating) wire connections and
splices. It is highly recommended that you
hire a qualified electrician to perform this
Other than complete replacement of aluminum wire with copper wire, there may
be numerous potential solutions for the
permanent repair of hazardous aluminum
wire connections and splices. However,
CPSC can recommend repair methods or
products only where there is satisfactory,
documented evidence that the methods or
products meet the following criteria:
• Safe. The method or product must be
safe and not increase the risk of fire or
other hazards.
• Effective. The method or product must
be effective and successfully eliminate or
substantially mitigate the fire hazard.
• Permanent. The method or product
must affect a permanent repair. Methods
or products designed to address temporary or emergency repair situations, but
which may fail over time, are not considered permanent.
Based on these standards, as of the date
of this publication, CPSC approves of only
three methods for a permanent repair.
1) Complete Replacement of Copper
2) COPALUM Method of Repair
3) Acceptable Alternative Repair
Method/AlumiConn Connector

Complete Replacement with Copper

Replacement of the aluminum branch circuit conductors with copper wire eliminates
the primary cause of the potential hazards,
the aluminum wire itself. Depending on
the architectural style of your home and
the number and locations of unfinished
spaces (e.g., basements and attics), it may
be relatively easy for a qualified electrician
to rewire your home. A new copper wire
branch circuit system would be installed,
and the existing aluminum wire could be
abandoned inside the walls. This is the best
method available; but for many homes,
rewiring with copper is impractical and/or
prohibitively expensive.

COPALUM Method of Repair

Install additional copper connecting “splice
assembly” wires between the aluminum wire and the wired device (receptacle, switch, or other
device). The connection must be made using only a special connector and special crimping tool
licensed by TYCO /AMP Corporation (COPALUM Crimp Method).
Permanent repairs using TYCO Electronics / AMP COPALUM Crimp Method must be conducted by
authorized electricians. These electricians are thoroughly trained by the manufacturer. This
method, based on extensive testing, is the only method considered by the CPSC to be a permanent
repair along with AlumiConn. connectors.

As an alternate to rewiring with copper,
CPSC recommends attaching a short
section of copper wire to the ends of the
aluminum wire at connection points (a
technique commonly referred to as “pigtailing”), using a special connector named
COPALUM to join the wires. CPSC staff
considers pigtailing with a COPALUM connector to be a safe and permanent repair of
the existing aluminum wiring. The repair
should include every connection or splice
involving aluminum wire in the home, including outlets, dimmers, switches, fixtures,
appliances, and junction boxes. The repaired system, with short copper wire extensions at every termination throughout the
home, permits the use of standard wiring
devices, including receptacles and switches.
The COPALUM repair method is recommended by CPSC on the basis of CPSC sponsored research, laboratory tests, and
demonstration projects. This repair method
has been thoroughly proven by more than
a quarter of a century of field experience to
provide a permanent, low-resistance electrical connection to aluminum wire. The
COPALUM repair method eliminates the
aluminum connection failure problems and
still uses the existing, installed aluminum
wire. The COPALUM repair method has
been shown to be practical for installation
in an occupied and furnished home.

Every connection of aluminum-to-aluminum or aluminum-to-copper wire should be
repaired in order to obtain the maximum
benefit from such repair work. All appliances connected directly to No.12 or No.10
AWG aluminum branch circuit wiring (e.g.,
dishwashers, cooling equipment, heaters,
air conditioners, and light fixtures) must be
repaired in addition to wall outlets, switches, junction boxes, and panel boxes.
The COPALUM connector is a specially
designed system that includes a metal sleeve
intended to be installed only with a dedicated power tool and crimping die to make
a permanent connection, that is, in effect,
a cold weld (the precision dies in the COPALUM tool compress the connector and
wires using upwards of 10,000 pounds of
force, as required to make the permanent
aluminum wire connection).

An insulating sleeve is placed around the
crimp connector to complete the repair.
The copper wire pigtail is then connected
to the switch, receptacle, or other termination device. An example of a repaired receptacle outlet is also illustrated below.

COPALUM Crimp Connector and its Specialized Installation Tooling
Recommended COPALUM Connector Repair

Acceptable Alternative Repair Method: AlumiConn

This product was introduced in mid 2006 by
King Innovation. If not adequately tightened, there is the possibility that connections could degrade.
The manufacturer may be introducing a new holding tool for the field that will assist the installer in
proper tightening.

CPSC staff recognizes that copper replacement may be cost prohibitive and that the
COPALUM repair may be unavailable in
a locality. Based upon an evaluation that
was, in part, CPSC supported,5
are advised that, if the COPALUM repair
is not available, the AlumiConn connector
may be considered the next best alternative
for a permanent repair. This repair method
involves pigtailing using a setscrew type
connector instead of the COPALUM crimp
connector in the repaired connections.
The AlumiConn connector has performed
well in initial tests, but is too new to have
developed a significant long-term safe
performance history as the COPALUM
repair. The repair should be conducted by a
qualified electrician because careful, professional workmanship and thoroughness are
required to make the AlumiConn connector repair safe and permanent.

Do Not Use Common Hand-Crimped
Connectors with Aluminum Wire

Remediation Methodologies That Are Not Recommended

Two other repair methods described
below are often recommended by some
electricians because they are substantially
less expensive than COPALUM crimp
connectors. CPSC staff does not consider either of these repairs an acceptable
permanent repair.

The use of electrical receptacles and switches marked COALR, CO/ALR, AL-CU or CU-AL have not
been recommended at this time by the US CPSC for aluminum wiring repairs.

Photo of author

Author D Laidler

I am David, economist, originally from Britain, and studied in Germany and Canada. I am now living in the United States. I have a house in Ontario, but I actually never go.  I wrote some books about sovereign debt, and mortgage loans. I am currently retired and dedicate most of my time to fishing. There were many topics in personal finances that have currently changed and other that I have never published before. So now in Business Finance, I found the opportunity to do so. Please let me know in the comments section which are your thoughts. Thank you and have a happy reading.

Thank you for visiting

Leave a Comment