Nah, but I'll bring back enough to do any of my own u-do-it projects.
In the discussion of aluminum wiring much was made of improper
installation. Well, wire nuts are inherently difficult for the
amateur to install properly, and not that easy for the professional,
though often taken for granted.
There are least two reasons they are not acceptable in Europe.
One is that they are uninspectable. After you put a pigtail together,
you really have no idea how much wire stayed in contact under the wire
nut, if any. And even if you don't want to admit you never screwed up
one of these yourselves, you must have seen a bad job by others. This
is especially true with solid or mixed wire, not so bad with stranded
The other is that the clamping pressure is indirect. While it depends
on how hard you twist the nut, the force is caused by the thickness of
the wire bundle and how far in to the wire it goes - and you can't
tell either under the wire nut.
while you can certainly use the wrong size chocolate block or not do
it tightly enough, you can see the screw forcing the wires together,
and the harder you turn the screw the harder they press. It is a very
secure and checkable connection method.
I bet if wire nuts were transparent they wouldn't be as popular.
Not believe so much as take for granted.
Look here. www.phoenixmfc.supanet.com
It's not so much that wire nuts can't work, just that there's a more
secure and more foolproof way, at about the same cost.
Yeah, that was dumb.
I did google image search with terms "chocolate block electrical" and
got a nice set of photos of chocolate blocks, then cut and pasted the
link which was showing. Hey, i was born before 1980 so officially I
am a digital immigrant, not a digital native.
On 06 Jul 2008 18:11:42 GMT,
email@example.com (stancomm) wrote:
I have never seen any aluminum wiring in branch circuit wiring.
I was surprised to learn it existed.
I would also be surprised to learn anyone knowledgeable enough to have
concerns about splicing aluminum to copper would truly post it openly
in a world wide forum.
Quite a number--anywhere a branch circuit caused a fire and that wiring
was Al would be, fundamentally, a case.
The problem isn't with the sizing of the conductor or the ampacity of
the wiring; it's owing to the tendency of Al to oxidize which leads to
higher resistance which causes resistance heating and the mechanical
properties in which it creeps leading to reduction in fitting tightness
which also raises resistance.
After about '72 when Al wiring w/ differing alloy properties started
becoming available as well as an awareness of the problems and improved
connectors and procedures, the risk began to go down somewhat, but it's
still statistically much higher than Cu -- I believe I've seen CPSC
numbers of roughly 40:50X higher risk.
The best information on aluminum branch circuit *connections* I have
seen is at
(one branch of the site metspitzer posted)
The advice is for a wide variety of fixes, from minimal to replacement
The information is based on extensive testing for the CPSC (which was
apparently headed for a recall of aluminum wiring).
One of the failures, which is probably still shown on the inspect-ny
site, is aluminum wires with a wire nut on them. There is enough oxide
that direct contact between wires is minimal. The spring on the wire nut
cuts through the oxide with the current then through the spring. The
spring is not intended to be current carrying, and a couple turns of
spring turn into a red hot space heater. (This comes from the testing
for the CPSC.)
AFCIs (since this year) can detect arcing at loose connections. They
won't detect "glowing" connections as above.
The advice for pigtailing in the paper above is apply antioxidant,
abrade, twist, apply wire nut. The paper has recommendations for wire
nuts and antioxide.
Interesting information on Ideal.
Alumicon should be available on the internet. The screw deforms the
aluminum which should break through the oxide. The same happens in
connections for bigger aluminum wire (though some manufacturers
recommend abrasion there also).
Was there a problem with aluminum branch circuit wire? UL thought so.
About 1971 they removed listing for aluminum wire and devices. New
standards had a different alloy (as dpb wrote) and CO/ALR devices. The
majority of the wire installed is the "old technology" stuff. The worst
problem was probably "old technology" wire with steel screws on devices.
The risk dpb refers to (as estimated by the CPSC) is that homes wired
prior to the revised UL standards (1972) are "55 times more likely to
have one or more connections reach Fire Hazard Conditions than is a home
wired with copper."
A 40:50X relative risk simply demonstrates how reliable electrical
wiring tends to be...
I believe there are something like 40- to 50,000 electrical-related
fires annually--I've no real number of the total number of residences
for the denominator but it must be in the 10's of millions...
So you are trying to say that out of 40,000-50,000 fires a year, only
ONE THOUSAND involved copper wired homes That is what 40-50x means
for you math challenged
This is still a scare story from a home inspector web site
(inspect-NY) and a political organization (CPSC)
NFPA and U/L express concerns that the proper wiring devices are used
and that the work is done by professionals but they do not have the
"sky is falling" attitude I see in these articles. The Ideal 65
wirenut is an example. It is still listed. I agree the Alumicon is a
better device but I think CSPC recommending Copalum as the "only"
solution may have more to do with a well placed campaign contribution
If you like to dig up statistics, see how many fires have occurred in
aluminum homes in the last 20 years where harry homeowner did not
alter anything. I bet you will find sloppy installations caused most
of the early aluminum fires and if nobody screwed with it, a good
installation is still working fine. CO/ALr devices pretty much made
the problem go away in houses wired with them. The brass screw expands
and contracts at virtually the same rate as aluminum so it doesn't
have the creep problem you have with the regular steel screw. A
properly made joint is gas tight so there is no oxidation.
In fact, in testing an aluminum wire in an aluminum lug like the
Alumicon actually performs better than copper wire when thermal cycled
... noalox or not.
If you have an aluminum wired house you should be vigilant to arcing
problems and I would even go as far as looking at the devices with an
IR thermometers (pretty cheap these days. But I would not get crazy
about it and I wouldn't start pulling things apart "just to check". I
still believe that once they shook out the sloppy initial
installations, most problems were handyman inflicted wounds.
BTW AFCIs are pretty much useless for aluminum type failures. There is
still the promise of a "series" fault detector but I don't think any
have actually hit the street. That is not what "combination" means.
Apparently the politicians at the CPSC invaded UL and cause the removal
of listings for aluminum branch wire and aluminum listings for devices.
The CPSC contracted with an independent research laboratory to
investigate aluminum connections, with supervision by a professional
engineer. Many thousands of connections were tested. Among the findings
was that "properly" made connections could fail. The testing was
apparently extensive enough for the CPSC to initiate a recall.
In the inevitable lawsuit the court ruled that aluminum wire was not a
"consumer product" and thus not under the purview of the CPSC. The CPSC
had also started a preliminary investigation of FPE breakers, and this
ruling was probably one reason the investigation was closed.
The last time I looked, most of the information on aluminum at the "home
inspector web site" was derived from the CPSC investigation. I find your
comments discrediting the "home inspector web site" and CPSC far below
your usual very good posts.
From a Mike Holt newsletter, referring to the "home inspector web site":
"This website contains extensive information for consumers and building
professionals regarding aluminum electrical wiring in residential
properties. The contents are the result of study of this topic and
represent the opinion of the author. Actual documents, authoritative
research, and government resources about aluminum wiring are here. This
is the most extensive and authoritative Internet information source for
aluminum wiring and related hazards."
And from Mike Holt (on FPE breakers), referring to the "home inspector
"Mike Holt's Comment: The failure rates for these circuit breakers are
significant, see the CPSC study. For Additional information about this
problem, visit the excellent website
http://www.inspect-ny.com/fpe/fpepanel.htm managed by Daniel Friedman
I didnt see a "sky is falling" attitude in the paper written by the
professional engineer and based on the extensive research:
The OP thinks the use has been restricted by Ideal. (I haven't looked).
I believe COPALUM came out best in the extensive testing done for the
CPSC. Perhaps you could deal with facts. Alumicon is quite new. [I would
use pigtailing, not COPALUM.]
You may (or may not) be right. Would be nice if stats were available.
One of the advantages of Alumicon is the screw deforms the wire which
breaks any oxide layer. The binding screw on a normal device can leave
the oxide layer. Not obvious to me that a "properly made joint is gas
I have not looked at other manufacturers, but SquareD has had
"combination" AFCIs out since 1-1-2008 (when "combination" types were
required by the NEC). I would be surprised if many other manufacturers
didnt have them too.
In late stages of connection failure there is likely to be a series arc.
Earlier stages, which can produce plenty of heat, it is a "glowing"
connection. An AFCI may (or may not) catch a glowing connection when
damage causes ground leakage and the AFCI trips on 30mA ground fault
[Note the problem is 15 & 20A branch circuits only.]
That is why I am skeptical of the CPSC articles. This is the same
culture that killed the Corvair ... for no particular reason.
It was certainly as easy to roll a 60's era VW bug and they left that
one alone. I smelled politics there too.
NFPA should be the people who have the fire statistics to make or
break this "problem" and they have never outlawed aluminum wire or the
Ideal 65. You could wire a house tomorrow with AA8800 aluminum wire
and CO/ALr devices and it would be code legal.
I bet you see it happen in the next few years.
On Sat, 12 Jul 2008 12:00:41 -0400, firstname.lastname@example.org wrote:
http://en.wikipedia.org/wiki/Aluminium_wire (aluminum is misspelled
in the link :)
In some States, Hazard Home Insurance will not cover homes with
aluminum wiring, and some insurance companies that claim to cover it,
have a higher premium than homes with copper wiring. Check with your
insurance company before purchasing a home with aluminum wiring.
Of course, that is improperly worded. Many homes have aluminum wire,
but not for branch circuits, and it is not spliced to copper.
Even properly made splices with aluminum to copper connections will
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