Interesting information/question. What testing method is used by the CPSC? Who designed the test procedure, and how was it derived? Was an electrical engineer involved?
The answer, the test method does not adhere to any published or approved testing method or specification, and no electrical engineer is involved with the testing, according to all the information I have been able to find. Kinda says something about their conclusions.
Not to say I have any faith in the Ideal Purple wire nuts - but no less than the faith I have in the CPSC.
The UL and CSA testing labs test to a standard, which is determined by electrical engi eers, and the methods are designed by and monitored by qualified electrical engineers. Do they always get it right??? Nope. But I think they have more than a fleeting chance of hitting the mark
- being they know what the mark is, what it means, etc etc etc.
The testing was at Wright-Malta Corp and was run by a PE.
He wrote a report with recommendations that has been revised a couple times
formatting link
There were many thousands of connections under long-term testing.
In addition to expansion, a major problem with aluminum wire is surface oxidation. A thin oxide layer rapidly forms, and it is an insulator. In a wire nut connection there may be little actual contact between the wires because of the oxide. Most of the contact may wind up being the metal spring in the wire nut, with a couple turns carrying the current. The spring is not intended to carry the current, and at relatively high current through the connection the spring can get red hot (probably what is happening in fig 1 in the report).
The glowing spring will not trip an AFCI because there is no arc.
The author recommends, in general, applying antioxide paste, abrading the surface to remove the oxide, and making the connection with enough antioxide paste to protect the wire.
(The last instructions I saw for lugs on large aluminum wire were to wirebrush the wire and apply antioxide paste. A utility lineman said they were supposed to wire brush aluminum wire used in mid-span splices in their wire.)
The report has a couple pages on Ideal 65 wire nuts. They have an antioxide paste, but that does not fix problems with oxide already on the wire. Based on information provided I would not use them.
Alumiconn connectors were not in the original testing (they did not exist then) and initial results have been added to the report. They look like the best way to splice Al-Al or Al-Cu. Alumiconn uses set screws, and likely deforms the wire which can break through an oxide layer. Deforming the wire is likely why connections on large aluminum wire do not have the same problems as 15 and 20A branch circuits.
The new aluminum wire is harder, and not likely to "extrude" in heat-cycling at a connection.
Details of testing are not included. There are some details by way of what testing was not done on the Ideal 65 wirenuts.
One of the complaints that came out of the testing was that the UL tests used the revised aluminum wire for tests of other components. Most of the wire actually in use is the original wire. The CPSC asked UL to revise their tests and UL didn't.
The CPSC appears to have been headed for a recall of aluminum wire, which would have been enormously expensive. In the inevitable law suit the court ruled that aluminum wiring was not a consumer product and not under the purview of the CPSC. (This may have been part of the reason the CPSC dropped an investigation of FPE breakers. They had some initial testing done which was not reassuring.)
Depends on your definition of "harder" The new wire is less stiff, and less likely to crack when bent.
There is actually more of the "revised" wire in use (at least in Canada) than the "original" wire.
Used "as" a "consumer product" aluminum wiring is a lot more dangerous than when used, as designed, as a professionally installed product. Same with the ideal 65 wirenut. (not impressed with the wirenut in any event, but "properly installed" they have never failed under testing.) Proper installation involves disruption of the oxide layer and sealing with the antioxide paste. If not properly installed, and then disturbed (by moving the wires to replace the outlet or switch) failure is pretty well guaranteed.
100%. PROPERLY INSTALLED aluminum has proven to be a very reliable product - particularly the revised wire. Properly installed WITH proper wiring devices (co-alr) it is as good as copper.
About 1965 copper prices went up and aluminum wire started to be used for 15 and 20A branch circuits. UL CU/AL rated devices appear to have come out in the late 60s because of problems. There were still problems and about 1971 UL removed the listing for aluminum wire, devices and wire nuts. New UL standards came out about 1972, with a new aluminum alloy and CO-ALR devices. Use died out about 1973.
UL responded to problems that went far beyond workmanship. Steel screws in older devices were a particular problem.
Actual tests have shown that connections made according to manufacturers instructions can fail.
The vast majority of 15/20A aluminum branch circuits in the US use "old technology" wire. UL tests of CO-ALR devices and wire nuts are made with the "new technology" wire, which is not the bulk of what is installed here. And the "new technology" wire has the same oxide problem that the old wire has.
(The older CU/AL devices, and those from before that which are not specifically rated for aluminum are certainly also around.)
I have not seen instructions for devices that include abrading the wire and using paste.
I doubt Ideal 65 instructions include abrading the wire, or twisting (another recommendation based on testing). Ideal 65 appears to be rated only Al-Cu now. They do not have Al-Al combinations.
The CPSC previously recommended only pigtailing with COPALUM splices (which I think you commented on). They now also recommend AlumiConn splices, which are easily installed.
Aluminum branch circuits can be safe. But they have a lot more potential for failure than copper.
Well, the USA definitely moved to aluminum a lot quicker than Canada did - took longer for CSA to approve the stuff than it took UL - so in Canada there is a LOT less OT than NT aluminum wiring. My dad was an electrician, and he only installed a very small amount of the OT aluminum - and he hated the stuff. The NT aluminum was "like working with copper, but thicker" - #12 bent about like #14 copper, but took up more space.. He never stripped aluminum wire 'till he was ready to make the connections - while in the insulation it didn't oxidize - and he was always carefull not to nick the conductor - but unlike the OT wire you COULD bend it twice. Make an eye, straighten it, and make the eye again, without snapping the wire. The OT stuff was like working with iron wire.
HomeOwnersHub website 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.