House, circa 1970, has aluminum wiring. Outlet recently arced and
overheated. Electrician pig-tailed on some copper wire using wire nuts.
Another outlet is giving problems and we are motivated to fix the whole
Internet research suggests that the CPSC recommends only COPALUM fittings
from Tyco. However, Tyco tells me that it has no certified installers in
Virginia. (We're in Richmond.)
CPSC also says that using wire nuts and pig-tails may be worse than the
original. This is a fine pickle...
Has anyone done are aluminum wiring repairs any other (safe) way?
They are trying to sell you something...........
Al is used every day by every utilitiy in the US. Here in Phoenix every new
house with a circuit over 30 amps has AL conductors.
CU to AL connections, wire nuts has been the standard for some time IF you
can not get the AL- CU devices. My home has AL circa 1971 and pigtails on
some devices and AL-CU devices every where else. Most AL devices do not have
a "stab in"connection. They use screws for the connection. Finding the
devices at a decent price is the real trick. That is why people pigtail.
A tight connection is necessary with AL. Wirenuts when twisted together
properly are acceptable.
This is the third home I have owned with AL wiring.
Do you know anyone who owns a meggar? You can test the circuits one by one
or the whole house at once. (power off NOTHING plugged in). Some one who
is familar with a meggar can tell you if you have any problems with the
insulation. I have even found loose connections using a meggar.
Service entrance conductors connections use Aluminum rated lugs and
connectors and an antioxide paste. Branch circuits are more problematic.
I agree that wirenuts should be reliable if they are rated for aluminum
Aluminum connections have 2 problems.
Aluminum expands more than most metals. When an aluminum wire in a lug
made of another metal conducts current it gets warm and expands and it
may be compressed in a lug that does not expand as much. This makes the
connection looser with a higher resistance so on the next heating cycle
it gets a little hotter and looser. Lugs used with aluminum should be
listed for this use as referenced above with CuAl devices. I would
trust a wirenut more than a device if the wirenut has a "live spring"
that deforms when twisted over the wires and maintains a spring
compression on the connection.
The second problem is that aluminum is very reactive. A clean surface
will rapidly oxidize. This keeps the aluminum shiny since aluminum
oxide is clear, but aluminum oxide is an insulator. This problem is
solved by coating the conductor surface with a paste made for this
purpose. A common one is Noalox (no-aluminum-oxidation). I would
suggest coating the wire before wirenuting it.
Note that these problems can occurr at any aluminum connection including
original wirenut connections and at connections to circuit breakers.
A megger measures high resistances using a relatively high voltage. In
this case I presume you would be measuring the resistance to ground. I
don't see how this would find problems or loose connections unless there
is a carbon path to ground. A megger will probably destroy GFCIs.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.