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#173585 01/13/08 10:03 PM
Joined: Jul 2007
Posts: 265
W
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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.


Jimmy

Life is tough, Life is tougher when you are stupid
Joined: Feb 2004
Posts: 1,438
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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.

Joined: Jan 2005
Posts: 5,316
Cat Servant
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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.

Joined: Apr 2003
Posts: 362
Member
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.


Ob


Choose your customers, don't let them choose you.
Joined: May 2003
Posts: 1,157
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Originally Posted by renosteinke
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.


http://www.tnb-canada.com/en/catalogues/online/comresconstruction/pdf/c5/09_marrcat_e.pdf

Joined: Jul 2004
Posts: 272
A
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dougwells #173596 01/14/08 10:20 AM
Joined: Jan 2001
Posts: 1,044
Tom Offline
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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.


Few things are harder to put up with than the annoyance of a good example.
Tom #173599 01/14/08 11:33 AM
Joined: Jul 2004
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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.


Greg Fretwell
Tom #173600 01/14/08 11:35 AM
Joined: Jun 2007
Posts: 301
J
Member
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.

Last edited by JValdes; 01/14/08 11:39 AM.
JValdes #173601 01/14/08 11:44 AM
Joined: Jul 2004
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G
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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) wink


Greg Fretwell
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