A lot of information on aluminum wiring has been collected at
which also includes web links. Information below is derived from this
site. The best of the links is
which is based on information derived from extensive tests at the
IDEAL #65 TWISTER
The Consumer Product Safety Commission (CPSC), reacting to fires caused
by aluminum wiring connections, contracted with Wright-Malta Corp., an
independent test laboratory, to do extensive testing. Some of this
testing was done on the Ideal #65 Twister wire-nut. This wire nut
appears to be a standard Ideal wire nut with antioxide paste inside. The
testing found that the Ideal #65 was not better than other wire-nuts
that were not listed for aluminum wire. (Information at
topic "D"). In addition to failing, the Ideal plastic shell and included
antioxide paste burned. (There is a multipage slide show of a
presentation to the CPSC from the Wright-Malta lab at:
This includes pictures of the Ideal #65 burning.) As a result of the
laboratory tests, the CPSC requested that UL change its test procedures
to be more realistic. Ideal told the CPSC that "the Ideal #65 was not
intended for use for [pigtailing retrofit], but only for such
applications as connecting lighting fixtures and ceiling fans. Ideal
committed to CPSC to change its advertising and instructional
information accordingly, but did not follow through on that commitment."
WIRE-NUTS ON ALUMINUM WIRE
The Wright-Malta Corp. tests found that because of surface oxide, there
is poor initial wire-to-wire contact to aluminum wire(s). The steel
spring in the wire-nut cuts through the oxide and makes contact, so
initally about 60% of the current flows through the spring. Over time
and use, the contact between the wires may be reduced, sometimes to
zero. The contact from aluminum to spring may also be reduced so only a
small part of the spring is carrying the current. However steel is not a
good conductor. Tests found a 2 volt drop across the wire nut through
the spring at 17 amps. This is only about 0.1 ohm resistance, but it is
a 34 watt heater. At this current level the spring is red hot. In other
tests, the spring is red hot at 12 amps. This destroys the insulation on
the wires and the wire nut and can start a fire.
THE NEW ALUMINUM ALLOY WIRE HAS THE SAME OXIDE PROBLEM AS THE OLD WIRE.
The only fix recommended by the CPSC is the COPALUM compression sleeve
that makes a cold weld to the wires.
topic "C" and "A", gives a detailed procedure for using wire-nuts with
aluminum wire. A critical part is applying antioxide paste to the
stripped wire then abrading the wire to remove the oxide. Know anyone
who does that, huh?
I have seen (and purchased but not yet use) those "poke in" connectors. I
don't even know if they are rated for Al. But you seem to be saying that
the ONLY way to go for the "little stuff" is a hard crimp! Screws just
aren't "gud enuf."
Should we start to worry about the "big stuff" used for electric stoves or
from the meter to the service panel?
(I don't know what the "poke in conectors" are.)
The only method recommended by the Consumer Product Safety Commission is
the COPALUM high pressure crimp system. The crimps replace all wire nuts
and a copper wire is pigtailed out at devices. They specifically advise
against using wire nuts. (But see paper below for a wire-nut use.)
Wire nuts, as well as connections to devices, have caused problems
including fires. My understanding is the new alloy and CO/ALR devices
solve the expansion problem but have the same oxide problems. Wire nuts
with the new alloy should have the same oxide problem as before.
The best information I have seen is at
which is a paper based on information derived from extensive tests at
the Wright-Malta Corp. for the CPSC. I covers a WIDE RANGE OF OPTIONS.
Anyone with an interest in aluminum wire 15 and 20 amp branch circuits
you should look at the paper.
- information on the options to reduce aluminum wiring risk
- information on COPALUM crimp connections (mentioned above)
- DETAILED PROCEDURE TO USE WIRE-NUTS WITH ALUMINUM WIRE to pigtail a
copper wire or to replace existing wire-nuts, including brands to use
- description of how wire-nuts fail; existing wire-nuts should be
- discussion of problems with Ideal #65 wire-nuts (the only UL listed
wire-nut for aluminum)
- how to install Ideal #65 wire-nuts, if necessary
- detailed procedure to connect aluminum wire to (CO/ALR) switches
- procedure to connect aluminum wire to circuit breakers
- if not making the changes above, what to do with existing system
- wiring installed after about 1971 with the new wire is more
reliable (if installed correctly) at device connections, but it has
essentially the same oxide problems as the old wire; this is
particularly a problem at wire-nuts; the information above is applicable
to the new wire
- also other very useful information.
I havn't heard of problems with service size and larger aluminum wire.
The connection clamps have a large area and the procedures to use are
well known to electricians.
Stove size stuff I havn't heard of problems. I would use Al listed split
bolts over wire-nuts and devices must be listed for aluiminum - along
with antioxide paste. The device connection clamps are a lot better than
the binding screws used on switches and receptacles. Are circuit
breakers listed for aluminum wire? Could split bolt a copper pigtail.
And I would think strongly about applying paste and then abrading the
wire as described in the paper.
Perhaps you could talk about the errors you found at the link above
insead of presumed problems with home inspectors which may or may not
include the inspector running the base web site.
As I clearly said in my last post, the information at the link above is
the result of extensive experiments done by the Wright-Malta Corp. under
contract from the CPSC. Or are they both suspect also. Papers on this
subject, from the Wright-Malta employee (who is not a home inspector)
that wrote the paper in the link above have been given at IEEE
conferences and appeared in IEEE Transactions. Based on the tests at
Wright-Malta, the CPSC requested UL change their standard for testing
aluminum rated wire-nuts.
From your other post - "it is a moot point"? 2 million homes are wired
with old technology aluminum wire from about 1965 to 1973. You may find
it hard to believe, but failed connections in those wiring systems have
caused fires and killed people. Because of these problems, UL removed
its listing on aluminum wire and devices in 1971. UL chaged its
standards and started listing devices which are marked CO/ALR and the
wire alloy was changed.
Aluminum branch circuit wiring continues to be a hazard. The link above
gives a number of options for handling the wiring in those homes.
Your apparent disregard of science-based information indicates you may
have a bright future in the Bush administration.
Bud this thread was about NEW installations not something during
I was referring to the aa8000 alloy
It should be noted that most of the problems with the older wiring was
sloppy installation or homeowner intervention. That is witnessed by
the number that DIDN'T have any problems in the last 3 decades,
BTW these are the Nationally Recognized Testing Labs
(NFPA and OSHA)
MET Laboratories, Inc. (MET)
914 West Patapsco Avenue
Baltimore, Maryland 21230
Intertek Testing Services NA, Inc. (ITSNA)
(formerly ETL, Inchcape)
3933 U.S. Route 11
Cortland, New York 13045
Communication Certification Laboratory, Inc. (CCL)
1940 West Alexander Street
Salt Lake City, Utah 84119
Canadian Standards Association (CSA)
(also known as CSA International)
178 Rexdale Boulevard
Etobicoke (Toronto), Ontario M9W 1R3
SGS U. S. Testing Company, Inc. (SGSUS)
(formerly U.S. Testing/California Division)
291 Fairfield Avenue
Fairfield, New Jersey 07004
Email: rich email@example.com
Southwest Research Institute (SWRI)
6220 Culebra Road
Post Office Drawer 28510
San Antonio, Texas 78228
Wyle Laboratories, Inc. (WL)
7800 Highway 20 West
P.O. Box 077777
Huntsville, Alabama 35807
Entela, Inc. (ENT)
3033 Madison, S.E.
Grand Rapids, Michigan 49548
Underwriters Laboratories Inc. (UL)
333 Pfingsten Road
Northbrook, Illinois 60062
FM Global Technologies LLC (FM)
(also known as FM Approvals and formerly Factory Mutual Research
1151 Boston-Providence Turnpike
P.O. Box 9102
Norwood, Massachusetts 02062
TUV Rheinland of North America, Inc. (TUV)
12 Commerce Road
Newtown, Connecticut 06470
Electrical Reliability Services, Inc. (ERS)
(also known as eti Conformity Services and formerly Electro-Test, Inc.
3470 Fostoria Way, Suite A
San Ramon, California 94583
Applied Research Laboratories, Inc. (ARL)
5371 NW 161st Street
Miami, Florida 33014
National Technical Systems, Inc. (NTS)
1146 Massachusetts Avenue
Boxborough, Massachusetts 01719
NSF International (NSF)
789 Dixboro Road
Ann Arbor, Michigan 48105
Curtis-Straus LLC (CSL)
527 Great Road
Littleton, Massachusetts 01460
TUV Product Services GmbH (TUVPSG)
Ridlerstrasse 65, D-80339
TUV America, Inc. (TUVAM)
5 Cherry Hill Drive
Danvers, Massachusetts 01923
The National Fire Protection Association, in the NEC Digest, Spring
2004, repeated CPSC findings on aluminum wire:
"In 1974, the CPSC determined that hazards associated with aluminum wire
systems present "an unreasonable risk of injury or death" and later
filed suit against more than two dozen manufacturers of aluminum wire
and devices used in these systems.
"According to a report published by the CPSC, homes 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 is a home wired with copper."
The NFPA, as you probably know, creates the National Electrical Code. In
2004 they, along with the CPSC, seem to still feel that aluminum wiring
poses a risk.
From alreduce.htm: "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
One of the most significant findings of Wright-Malta was that aluminum
wire connections made in accordance with industry standards and
manufacturer recomendations can fail, possibly resulting in a fire. That
is why the CPSC moved to regulate the industry. "Sloppy installation" is
not required. And "sloppy installation" as a cause remains at the level
of opinion unless you have an investigative source.
I have doubts the NFPA recognizes this list. From the 2003 NEC Style
Manual: "Use of the terms "Nationally Recognized Testing Laboratory" or
"NRTL" shall be avoided. .... [It] is an OSHA program for the
accreditation of laboratories that test products for the workplace and
is not to be applied generally in the NEC."
I have no idea what the relevance of the list of laboratories unless it
is to show that Wright-Malta isn't on it. But the list is of labs is
those recognized by OSHA to qualify a product as meeting a standard -
for electrical products it is typically a UL standard. That is not what
Wright-Malta was doing.
Incidentally, the longer story of of the CPSC involvement is that it was
alarmed by fires from aluminum wiring systems (including deaths)
contracted with Wright-Malta to make tests. Wright-Malta wound up doing
extensive tests of aluminum connections (extensive: "in 1982, there were
approximately 7,500 aluminum and aluminum-copper connections on
long-term test, plus (for comparison purposes) a substantial number of
copper-wired connections.") My understanding is that the CPSC
recommended a recall of aluminum wire. In the obvious court case that
resulted, the court ruled aluminum systems were not "consumer products"
and thus the CPSC did not have perview.
The CPSC must have considered the Wright-Malta test data to be extensive
enough and have enough validity to initiate an action against the
industry and withstand the court case that would obviously result.
The paper at the web page contested before,
is based on the Wright-Malta test data extended to practical fixes for
existing wiring. From section 1H of the paper (which is about the new
alloy wire you are fond of):
"[The new] alloy aluminum wire may have lower probability of overheating
at the binding head screw connections. There is little improvement in
the probability of overheating in other types of terminations, however.
In particular, the alloy aluminum conductors show high failure rates in
tests with twist-on connectors [aka wire-nuts].
"The alloy wires have improved mechanical properties but may have
essentially the same electrically-insulating oxide surface film. As with
the "old technology" ("EC" grade) aluminum wire...."
The point about wire nuts and oxides is the one I made in my original post.
I guess that is why you are supposed to torque the fitting to specs.
That assures a gas tight connection. Since most lugs these days are an
aluminum alloy and aluminum wire actually tests better than copper in
one of them, some of this hysteria is misplaced.
Read the topic title, this is NOT about 10ga and smaller wire. You
would ber hard pressed to buy some, even if that was what we were
I know folks love to cite the NY-Inspect site, but I have to bear in
mind that is the same city that banned Romex for any application until
very recently so some of this may be IBEW mantra.,
My original post was in response to your post which, talking about the
"newer alloy", said: "Used with CO/ALr devices it would probably be OK
but nobody will actually try it. .... Old legends die hard tho." That is
15 and 20 amp branch circuits on 10 ga and smaller wire.
All subsequent posts by you, have been about 15 and 20 amp branch circuits.
> I know folks love to cite the NY-Inspect site, but I have to bear in
I have repeatedly pointed out that the paper at:
is based on extensive tests at Wright-Malta and was written by a PhD
Professional Engineer from Malta.
You have said it was "a 'home inspector' site <insert home inspector
joke here>" when the paper was not written by a home inspector. And now
you tie it to New York City and the IBEW, both of which have absolutely
You have at no point challenged the CPSC view of aluminum wiring,
Wright-Malta test results or the contents of the paper. I be happy to
communicate on one of these topics. Others are pointless.
And I am more convinced that your disregard of science-based information
indicates you may have a bright future in the Bush administration.
He said the post was about NEW construction. He said it (discussion
of 15/20A aluminum wiring in new construction) is a moot point.
He said the thread is not about 15/20 ga wiring. Either you can't
understand what was posted or you are looking for an argument.
Please take your contentious posting eleswhere.
(At the same time as the "moot point" post there was a simultaneous "a
'home inspector' site <insert home inspector joke here>" post to which I
I've read back through the thread, and as far as I can see all my
responses directly follow from what [ firstname.lastname@example.org] said. Did I miss
I particularly object to discrediting a Professional Engineer-author by
associating him with an unrelated home inspector - "<insert home
inspector joke here>" (and later New York City and the IBEW). Some of my
posts after that were overwritten.
I am sorry if I offended you.
I have just had bad experiences with home inspectors and when asked
they say they are not code inspectors so I have to question "what
standard do they use"?
It is particularly suspicious when the only "answer" is a single
product with limited acces to installers.
and I stand by that.
Then the topic got switched to the "run for your lives, I think I saw
an aluminum wire" rant you get from people who don't know the
difference between tinned copper and aluminum. I agreed there was a
early failutre rate of wire that was installed in the 70s but there is
plenty of evidence to show that the problems were caused by bad
workmanship and homeowner intervention as much as a bad product. The
statistics they toss around are from the late 70s and 80s.
I am always skeptical of any mantra that ends up with one and one only
solution, particularly when it is a tightly licensed and controlled
commercial product like the Copalum. Starts making me wonder if that
obscure lab was getting a taste of the sales.
I agree a person with aluminum should be extra vigilent about unusal
electrical symptoms but actually going in and screwing with something
that is working may be more dangerous than leaving it alone.
That still has nothing to do with installing aa8000 wire and COALr
Not busting on anyone really, if it comes across as such sorry. Reread what
he said about selling it to people. You do not sell service drops to people
I just reread his 2/3. At first I thought he mentioned two hots and a bare
ground. I know see that he had it right.
My gripe is the term "probably". The term probably and any mention of
cabling under 12/2 should not be in the same sentence. Actually probably
and any current flowing cable should not be in the same sentence.
Not something to guess at, and is something to leave for a person in the
know, or licensed.
If by the Code you mean the NEC, then you are wrong. Utilities don't follow
the NEC when sizing service drops. 2/3 means #2 aluminum, 3 conductors.
That would be the "norm" for short service drops for 200 amp services. If
the service gets a little long, then 1/0 aluminum would be used.
Keep in mind that you cannot compare the conductor ampacity ratings in the
NEC with those used by utilities. Overhead service drops by utilities are
governed by the NESC not the NEC.
Charles Perry P.E.
Is that the same brand as the 29cent 15amp outlets?
Could never figure out how they can sell something so cheap. Obviously they
are cheap outlets, but who in the world can even make cheap ones that cheap?
I can only assume that they are "loss leaders".
If you can read this, thank a teacher. If it is in English, thank a
The service drop (the overhead conductor) might be #2 but as Mr Perry
says, that is the utility string wire in free air under the NESC. As
soon as you get to the service point where they splice to the service
ENTRANCE cables at the service head the minimum size is 2/0 copper or
4/0 alumiinum. An underground service lateral will use the larger wire
since it is not "free air".
That is for a dwelling only. If this is any other occupancy you would
use 3/0 copper or 250Kcmil aluminum
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