Have to do some work in a house with aluminum wired branch circuits. Question no.1: is there an approved(and safe) way to make an al/cu joint? Aside from the obvious tear it out and start over, anyone have any suggestions, comments, jokes? Thanks in advance for your input.
AMP makes a tool which they will "rent" to you for an exorbitant amount of money, then you have to purchase the crimps from them for even more $$$$. AFAIK, this is the only means I know of as a permanent solution to AL/CU splicing.... otherwise...
There's the purple Ideal wirenuts that have been debated on this forum before about their fitness for the purpose of AL/CU splicing, but I believe they are listed for that purpose...
Back in the day, they used to use 3M Scotchlock wirenuts on aluminum... The outer shell is a soft plastic, and the inner spring mechanism tends to expand with the aluminum conductors under load and maintain grip vs. the hard shell wirenut which tends to push itself loose.... I had decent luck with those when installed correctly... one problem with that nowadays though...
Scotchlocks are only listed for CU wire now! But I feel this is more a matter of 3M not wanting the liability vs. an actual failure rate (purely my opinion though)
I do my best to avoid AL branch wiring and run a new circuit.
Oddly enough, I believe there's a variation of the Scotch-lock that is approved for permanent splices ... unlike the Ideal purple nuts.
King makes some set screw connectors for this purpose.
Thomas and Betts, I think, has the brand name "Marlette." These are approved for such splices, and commonly sold in Canada. You get to order them here.
The house I grew up in is wired with Al conductors. They are a pain in the #$% AAlmost all conections have been pigtailed with cu. A friend of my Dad's was a Union electrician back in the 70's, before there was a ul approved method. He simply used anti-oxident and either a 3m or b-cap. That was 30 years ago. I have now been in the trade myself 20 years, and done many additions and rework for my Mom and there has been no problems with his installation. This is all for what it's worth as no inspector would approve this installation today. The problem is not so much the expanding and contraction, as it is the screws backing out and then causing a poor connection causing carbon causing resistance and heat untill you have enough heat for fire. The expanding and contraction will literialy cause the screws to loosen.
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Oddly enough, I believe there's a variation of the Scotch-lock that is approved for permanent splices ... unlike the Ideal purple nuts.
King makes some set screw connectors for this purpose.
Thomas and Betts, I think, has the brand name "Marlette." These are approved for such splices, and commonly sold in Canada. You get to order them here.
Both the King setscrew connectors and the Ideal twisters (purple) will work but they both have the drawback of being large. This is a real problem with the small boxes used in mobile homes and if you use these devices, you'll end up adding a surface extension box to gain enough room for the connectors & wiring device.
I've run across the 3M with anti-oxidant in some homes in my area.These splices are still working fine after many years, but since this is not a tested or approved method, I can't recommend it.
I really believe that if you use the CO/ALr devices and the Kings or Ideal 65s for splices you would never have a problem. I still think 99% of the "aluminum" problem was workmanship. The builders who cut corners on materials were also cutting corners on labor and then you had homeowners in there "improving" their house with whatever they found at the hardware store. I wonder how many of these problems were in things Harry Homeowner or the handy man "fixed".
One thing that is evident is if that house was going to burn down, it probably already has. There are millions of homes that never had a problem.
A-Line.....Those connectors look good. How big are they? Any issues with box fill? My sister owns two condos and both have Al wiring. They never knew until I replaced all the recepts and switches for them. (Color change). All the recepts were daisy chained which I never do, but seemed to be better for the AL wire. No wirenuts. I can see no benefit to pigtailing with CU unless the connector is rated for this purpose. With one of the units I got a call about an "electrical smell" and found the water heater connections had overheated and seperated. (wirenuts). I took the Al cable all the way down to the WH connection screws and used crimp connectors to finish. Now that I see the connectors designed for this use I will go and redo the WH connections. Thanks
ps..I just checked out the pricing and I now will leave the HW heater alone.
I imagine the first guy who had the idea for the King device just cut a little chunk off a ground bus (listed CU/AL)
The problem is not so much the expanding and contraction, as it is the screws backing out and then causing a poor connection causing carbon causing resistance and heat untill you have enough heat for fire.
Where does the carbon come from? There's no carbon to speak of in the aluminum, in the contacts, or in the air it's immersed in.
I always have a couple of packs of the purple Ideal wirenuts in the truck. When I splice that old soft aluminum building wire I always wire brush and twist the conductors before I apply the connectors.
The major problem with the purple wirenuts is that according to the instructions, they can only be used for aluminum to copper connections, not aluminum to aluminum. So, if you have multiple aluminum wires to splice together in a box, like neutral connections, you need a lot of room for all the individual splices and the final connection for joining all copper conductors together. Very inadequate and quite a pain.
Alcan was at one of our IAEI meetings explaining the different alloys of aluminum and why the old style devices had problems. It basically comes down to the difference in expansion rates of steel screws and aluminum. If they have brass screws like the CO/ALr this rate is a lot closer and you don't see that problem. They were also pitching the new MC cable with the aluminum bonding wire. Time will tell on that one. I doubt that will be "wet" rated like most MC these days.
Thanks guys for all your input I am checking on a supplier for all of the connectors mentioned. Thanks again
I imagine the first guy who had the idea for the King device just cut a little chunk off a ground bus (listed CU/AL)
We have been using the King connectors for all the remod and repair work, so far no problem.
Check out the link below (hope it works). I was close to taking a job this year $100k+ but being employed full time at an industrial plant time was too short. My research and numerous discussions with insurance companies confirmed there is only one method approved by the CPSC. That is the Amp/Tyco CopAlum system. Cost per device can range from $35 - $50 each!
Aluminum wiring info
I've really got to challenge the link posted by rkukl.
That link has been floating around for at least a decade .... long before King Innovations got UL listings for their connectors. At best, it's simply obsolete.
Likewise, 3M - another company known for innovation and quality - has quite a few crimp connectors listed for use with either aluminum or copper wire. Since the barrels are themselves aluminum, and the joined wires never touch each other, it ought not matter if the wires differ from each other.
The CPSC has a pretty spotty record in matters electrical. I'd hardly look to them for expertise. Moreover, their endorsement of a proprietary product is questionable at best - notwithstanding that the method is essentially not available.
Moreover, simply using an approved device ought to allow you to change from one material to another, simply by using different screws.
Wow…, thanks for the great link rkukl,
After reading that article over I’ll definitely be canning those purple Ideal wirenuts for good. I always thought Ideal was a reputable company, so I don’t understand how can they even market that garbage.
You take the time and try and do things properly with the approved methods and then you find out you’ve been bilked. Very frustrating.
Just remember CPSC is a politically appointed organization not a NRTL. If we can't trust the U/L evaluation of the Ideal 65 we might as well delete the word "listed" from the code.
For what it's worth...
I have used the Ideal 65 occasionally over the course of several years. I feel comfortable with them.
The former head of the CPSC appears to be the one behind all the negativity regarding the purple twisters. Makes me wonder if he owns stock in the company that makes the high dollar CopAlum splice.
The CPSC is not responsible for approving anything electrical, only your local AHJ can do that.
If the purple twister is so bad, how come the CPSC hasn't issued a recall notice by now?
Purple twisters are UL listed, who do you trust, an independant 3rd party with many years of experiance in the industry or the aforementioned politically motivated agency?
IMO, the CPSC should stick to checking for lead in all those Chinese toys we're importing.