Technical Article:
Aluminum Wiring
March 2009
By
Skip Walker, MCI
Based In Part On An Article By
Douglas Hansen in 1999
There are about 2 million homes in
the U.S. that are believed to have solid aluminum
branch-circuit wiring. For decades this type of
wiring has been publicized as a potential fire and
safety hazard. Today, Americans are loading up their
homes with high-tech appliances and products that
draw more electrical current through these aging
circuits. Overloaded convenience circuits may
exacerbate the issues associated with older solid
aluminum wiring. This can result in overheated plugs
and receptacles that may result in a fire. Research
suggests that older solid aluminum wire, generally
wiring installed prior to 1972 may be more likely to
experience connection problems than post-1972 solid
aluminum wire or copper wired connections.
“You could say that electricity practically runs our
lives when you think of all the modern day
necessities that need it, yet most people are
unaware that electrical problems are factors in
nearly 150 home fires each day,” said Lorraine
Carli, NFPA vice president of communications.
“Electricity is a leading cause of home fires, but
there are things that people can do to avoid these
fires.” A free consumer information toolkit designed
to help individuals learn how to protect themselves
and their property is available at
www.NFPA.org.
According to the NFPA, electrical failures or
malfunctions result in an average of 19,100 home
fires each year. These fires cause more than 140
deaths, injure 1,400 people and account for $349
million in property damage. Statistics on fires
specifically caused by aluminum wiring are not kept
CPSC official’s say that what's upsetting is that
many homeowners still don't recognize the hazard
that solid aluminum wire represents. Although the
CPSC estimates that "tens of thousands" of
homeowners have heeded its advice and made
appropriate electrical system repairs, many more
have not. "All fires are of concern to us, but
electrical fires concern us more because they occur
behind the drywall and are hard to detect and to
react to. When it comes through the wall, it is a
fully involved fire," said Scott Wolfson, a CPSC
spokesman.
David Hannemann and his wife were made aware that
their home had aluminum electrical wiring when they
purchased their Washington, DC home over 22 years
ago. However, they waited almost 18 years to make
the fix that has been recommended by the Consumer
Product Safety Commission since. What prompted the
delayed response to this known fire hazard? "My wife
worked in insurance, and she suggested we'd better
do it," said Hannemann, a federal employee in
Washington, DC. At the time, an underwriter at his
wife's former agency "told her he wouldn't write the
line anymore" unless a house had been repaired as
the CPSC recommends, Hannemann said. This event
occurred several years ago.*
In researching this updated article, most insurance
companies would not comment directly on underwriting
policy. Of those that did, one indicated that solid
aluminum wiring might trigger a requirement for an
electrical inspection before a policy is issued.
Most representatives were unaware that
aluminum-wired houses posed any issue and indicated
that their underwriters were not inquiring about the
presence/absence of aluminum wiring. Insurance
companies go through cycles in policy underwriting.
When any kind of issue produces a string of
underwriting losses, the companies typically react
by enacting underwriting restrictions. This apparent
lack of insurance company concern on this issue
implies that solid aluminum wiring is currently
perceived to be a low risk issue.
The National Electrical Code® has recognized
conductors made of aluminum since for many years.
Aluminum wiring was UL listed for residential use in
1946. The use of aluminum wire for feeders and
service entrances was common by the early 1950’s and
continues today. In the early 1960’s, Kaiser
Aluminum and other aluminum manufacturers introduced
solid-wire aluminum non-metallic (Type NM) sheathed
cable. This wire was installed in the same manner as
copper conductors, often with disastrous results.
The problem with solid aluminum wire is not the
reduced current-carrying capability of aluminum. The
failures occurred at the mechanical connections.
This was especially true in the original aluminum
alloys. The safety hazards were well publicized.
There seems to be little verifiable research that
identifies the actual mode of the connection
failures.
The original NM cable aluminum alloys of the 1960’s
lost their UL® listing in 1971. NM wire using modern
8000-type alloys was first UL® listed around 1972.
Southwire® was the first company to gain a listing
for these new alloys. The newer alloys appear to be
far less trouble-prone than original aluminum
alloys. Today, the National Electrical Code®
requires aluminum conductor alloys be at least an
“AA-8000” series (section 310.14). These 8000-series
alloys exhibit much greater terminal retention and
have superior mechanical strength as compared to the
“old technology” wire. A piece of the old alloy
solid aluminum wiring can be broken by simply
bending it back and forth a few times, whereas the
8000-type alloy wire has far greater pliability and
holds up well to repeated bending/flexing.
In evaluating any older solid aluminum wiring
system, it is not always possible to rely on the
dates given above; older stock could have been put
to use long after superior products were available
on the market. The wide variety of methods and
materials used in these older wiring installations
means that all solid aluminum wiring installation
should be evaluated on a case-by-case basis.
Unfortunately, there is no one right answer that
applies to every dwelling with solid aluminum
wiring.
Solid aluminum alloy wire was only available as type
NM sheathed cable. Inspectors should be careful not
to mistake older tin-coated copper wiring for
aluminum wire. The dull-silver coating on older
rubber-insulated copper wire was necessary to
prevent the chemicals in the rubber from interacting
with the copper.
Older receptacles and switches used steel terminal
screws. The combination of steel screws and aluminum
wiring was bad and certainly would seem to have
contributed to connection issues. However, switches
and receptacles with steel terminals were also
problematic with copper wiring. In response,
manufacturers switched to brass terminal screws as a
way to improve overall connection performance. This
change occurred in the early 1970’s, about the same
time as the switch to 8000-type aluminum alloys
occurred. Unfortunately, there has been no research
into the performance of the old and new solid
aluminum wire alloys with both steel and brass
connections to determine what impact the terminals
had on connection performance.
It is our responsibility as professional property
inspectors, to report on any issue that impacts the
safety and habitability of the property. The
presence of solid aluminum wiring in branch circuits
is a recognized safety hazard and as such is a
reportable condition. There may be a temptation to
assume that since an installation is 30 years old
and has never been a problem that somehow it is ok.
That could be a potentially dangerous assumption.
Issues with electrical wiring are directly related
to the quality of the installation, the frequency of
use and load conditions. Proper workmanship is even
more critical with solid aluminum wiring. The fact
that a suspect connection has not failed can change
quickly when a new owner moves in. The new
occupant’s usage patterns may vary significantly
from the previous owners, i.e. they plug in a major
appliance at that receptacle with a marginal
connection.
It is always prudent to watch for the signs of
faulty electrical connections when inspecting any
property. Tell tale signs may include:
-
Are there sparks, smoke, or
the smell of burning plastic emanating from
receptacles/switches?
-
Are there receptacles and
switches that are warm to the touch?
-
Do the lights that flicker,
shine unusually bright or do the occupants
complain that light bulbs burn out quickly?
-
Do the occupants complain of
fuses that blow or breakers that trip for no
apparent reason?
Circuit testing devices such as the
“Sure-Test” and TASCO Inspector lll circuit
analyzers are capable of measuring voltage drop at
receptacles. In theory, these devices might be used
to identify potential loose connections. In
practice, these devices may not be reliable and are
likely to produce false positives.
Infrared/Thermography cameras may also be used as a
tool to isolate hot spots in the wiring system. The
use of specialized tools such as circuit analyzers
and infrared cameras is beyond the scope of a
general property inspection as outlined in our CREIA
Standards of Practice and most other nationally
accepted standards of care. The simplest approach
for us as inspectors is to clearly recommend to the
client that the electrical system be fully evaluated
by a qualified electrical contractor or consultant
familiar with the issues involved and the available
repair methods.
Many of these older homes have small main service
panels that could stand upgrading anyway. For owners
also faced with aluminum wiring in their homes,
there are several viable repair alternatives. The
homeowner may choose to replace the solid aluminum
wire with copper wiring. It is also possible to make
less invasive repairs by “pig-tailing” copper wires
onto the solid aluminum at all connection points.
For that, there is the Copalum® system, from AMP
Industries, the AlumiConn® Connector by King
Innovations, the Purple Ideal 65® wire nut connector
and “Kearny” split-bolt connectors. Unfortunately,
pig-tailing repair methods are not a cure-all. In
some cases, they may do more harm than good. The
repeated bending strain imposed on the conductors
during the retrofit process can damage the wire
inside its insulation. This is especially true on
pre-1972 older aluminum alloys that are inherently
more brittle. Receptacles/switches may also be
replaced with devices listed for direct connection
to aluminum (CO/ALR rated).
The Consumer Product Safety Commission actually made
an outright endorsement of
AMP Industries Copalum® system. This has lead
many to believe that no other viable repair method
exists. The Copalum® system carries a relatively
high cost per connection. The Copalum® system
requires the consumer to use an electrical
contractor certified to participate in the Amp/Tyco
program. The system requires a special tool to make
the connections. The AlumiConn® Connector by King
Innovations was listed by UL® in mid-2006 for solid
aluminum wire pig-tailing repair applications. As
with all repair methods, the manufacturer’s
installation instructions must be adhered to
rigorously. Unlike, the Copalum® system, the
AlumiConn® connector is readily available and does
not require a special tool to use. The AlumiConn®
connectors may be found on the shelf at big box
retailers in many areas. Wide product availability
can be both a blessing and a curse. It makes this
repair system accessible to individuals that may be
improperly trained/ill equipped to successfully
repair the system property.
The Purple “Ideal 65®” wire nut has a UL® listing
for copper-to-aluminum connections. Like the
AlumiConn® connector, the Purple “Ideal 65®” wire
nuts are readily available. The Ideal 65 connectors
are listed for connecting a copper conductor to one
or two aluminum conductors. Curiously, they are not
listed for direct aluminum-to-aluminum connections,
possibly because the copper is needed as a heat
sink. The “Ideal 65®” is not without its detractors.
Most vocal is Dr. Jess Aronstein, a consulting
engineer in New York State. Aronstein has campaigned
to have the Ideal 65 product recalled. He presented
his case to the Consumer Product Safety Commission.
The CPSC declined to act on the information
Aronstein presented. Aronstein’s tests have not been
supported through independent third party testing.
It may be advisable to take Aronstein’s publications
with a grain of salt.
Aronstein’s papers on solid aluminum wiring and
other related information can be found at Daniel
Freidman’s InspectaPedia site:
www.inspect-ny.com/aluminum/aluminum.htm It is
possible that clients may find this information and
ask questions about it. As inspectors, we should be
aware of this information and be prepared to offer
unbiased counsel to our clients.
Split-bolt connectors (Kearney’s) are another method
that can be used. The split-bolts must be rated for
aluminum-to-copper connections. This method is labor
intensive, and really only practical for larger wire
sizes.
The switches/receptacles can also be replaced with
devices listed for direct connection. The National
Electrical Code® requires that devices directly
connected to aluminum wiring be rated “CO/ALR.”
“CO/ALR” rated devices have screw posts designed for
superior retention and compatibility with aluminum.
“CO/ALR” rated receptacles and switches may be
harder to find and cost about $3 - $5 more per
device than non-“CO/ALR” rated devices. There are
other disadvantages to replacement with CO/ALR rated
devices. What if a handyman or homeowner may
replaces a receptacle with a standard device later
on – not realizing the problems associated with
doing so?
The Leviton
website makes the following statement about this
issue: “CO/ALR switches and
outlets are required anywhere aluminum wiring has
been installed. The terminal screws on CO/ALR
devices are made of special materials and designed
to grip aluminum wire very tightly. STANDARD
DEVICES MUST NEVER BE USED WITH ALUMINUM WIRE.
Doing so is a code violation and dangerous because
it increases the likelihood of electrical arcing,
short circuits, fire and shock.”
A number of 1970’s solid aluminum wire systems were
assembled with copper pigtails between the aluminum
conductors and devices or fixtures. The copper
pigtails eliminate the problems posed by the direct
connection of aluminum to the devices. However, the
problem with this method is that the pigtail
connections themselves then become the weak point.
The connectors used in some of those older
installations may not be listed for
copper-to-aluminum connections.
Another defect commonly associated with older
aluminum wire is over fusing. Aluminum has
approximately 61% the ampacity of copper by size,
and in wire applications this translates to needing
15-amp breakers for #12 aluminum (aluminum wire is
not manufactured in 14 gauge). A 20-amp breaker does
not properly protect #12 aluminum wire. A number of
circuits in modern dwellings are required to be 20
amps, including the kitchen countertop appliance
circuits, bathrooms and laundry. To supply these
circuits with aluminum wire would require #10, which
would be rare in this application. #10 aluminum
requires 25-amp breakers, a size that is
manufactured, but is not allowed for multi-outlet
branch circuits. In the “real world” we may find #10
aluminum protected “incorrectly” by 30 amp breakers.
Some installations get around these issues by using
copper for the 20 amp circuits and aluminum for the
remaining circuits.
In some homes, dryer circuits have been improperly
wired with the #10 aluminum wire and should use #8
wire. An ongoing and common wire size issue with
larger circuits is the use of #6 aluminum with
50-amp range and oven circuits. This could
theoretically be allowed with aluminum type SER
service entrance cable and 75° terminations at least
until the adoption of the 2008 NEC (applicable in
California in 2011). The 2008 NEC removes the
exception for temperature limitation, and
effectively limits #6 aluminum to 40-amp circuits.
Another common use is to find aluminum used for
“home runs” with splices to copper for individual
branch circuits. In such situations, an inspector
might see aluminum wiring in a panel, but no
aluminum wiring at individual switches or outlets
because it has been spliced to copper for the home
runs.
Arc-Fault Circuit-Interrupter (AFCI) breakers may be
used to provide an additional layer of safety
protection on convenience circuits. However, the
AFCI circuit breakers must be the new “combination”
type in order to afford any protection. The
combination type AFCI devices can recognize the
signature pattern of arcing currents (and
distinguish these from the normal arcing that might
occur in a properly operating snap switch). The AFCI
breakers initially available were not combination
type devices and afford no protection against series
arcs resulting from loose terminals, or from glowing
arcs. The real life-safety potential of AFCI’s might
be realized by installing them with in dwellings
with solid aluminum or older knob-and-tube systems.
AFCI protection alone should not be considered a
substitute for re-wiring or approved pigtail type
remediation for solid aluminum wiring installations.
Washington, DC area homeowner Hannemann, who made
the repairs after 18 years, said the cost put them
off for a long time. "People are funny about this
kind of thing," he said. "It's a lot of money to
spend on something you can't see." When he finally
saw some of the burnt wire nuts, he said, he thought
the six-day retrofit was time and money well spent.*
There is a wealth of great information available
online regarding this issue for both our clients and
us. Inspectors and clients alike are encouraged to
read the documents available at
www.CPSC.gov. The
Loss Control Technical Information Paper Series
(TIPS) on Aluminum Wiring published by the Hartford
Insurance Company provides a simple and factual
overview of the issues. The document lays out
clearly the recommended repair options in an
unbiased manner. See the document online at:
The Hartford – TIPS Aluminum Wiring Loss Control.
The Professional Investigative
Engineers/Investigative Engineers Association
published a useful newsletter article that can be
found online at:
IENGA Aluminum Wiring Newsletter.
Aluminum wire is actually 200% more effective as a
conductor than copper by weight. For this reason, it
is used extensively in high voltage distribution
lines. In general, 99% of ALL electrical fires are
the result of installation/workmanship issues. In
the case of solid aluminum wiring, it is almost
always the connections that will fail – not the
material. Fortunately, we have some effective tools
to deal with this older, if not somewhat forgotten
safety hazard.
About the authors:
Skip Walker lives in the SF Bay Area
and has performed about 2,000 paid inspections since
becoming a CREIA member in 2003. Skip is both a
CREIA Master Inspector and an ASHI Certified
Inspector. Skip is an ICC Certified Residential
Combination Building Inspector and a F.I.R.E.
Certified Inspector. Skip is the education chair for
the Silicon Valley ASHI/CREIA Chapter. He also holds
a California Real Estate Appraisal Trainee License.
Skip may be reached at
HomeInspection@sanbrunocable.com.
Douglas Hansen lives in Marin County
California and is a nationally recognized expert on
code/inspection related issues and a primary author
of the widely acclaimed CodeCheck series. Douglas
started his inspection business in 1980 and was one
of the pioneers of the home inspection industry in
California. Douglas is now a full time author, code
consultant and educator, and a nationally renowned
lecturer on a wide variety of building and real
estate topics. He is also the author of Electrical
Inspection of Existing Dwellings. He is a licensed
contractor and is code certified as a building,
plumbing, mechanical, and electrical inspector. He
has served on several committees and the Board of
Directors of ASHI and CREIA. For several years, he
was on the faculty of the College of San Mateo
Building Inspection Technology program. Douglas may
be reached at
douglas@codecheck.com.
*NOTE:
The Hannemann Interview Quotes are from the
Washington Post Article: "What Owners Need to Know
About Wiring Dangers",
By Sandra Fleishman,
July 3, 2004. |