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CU/AL connectors for pigtailing


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Did a late '70's condo yesterday with aluminum wiring.

Feeder and branch wires had been "pigtailed" (well not really, read on) at the breakers and at the outlets.

I've never seen this type of connector used to connect copper & aluminum.

Can anyone tell me what type of connectors these are and if they are designed for use connecting copper & aluminum?

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They appear to me as the type of connector used to splice 2 wires into one or to splice two smaller wires with one larger one.


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This is not from UL and is dated, but it supports the idea that the Purple wire-nut is not the ulimate solution. Also years ago I had an email from a CPSC engineer saying that Ideal's Purple wire nut should be used for temporary repairs only. Unfortunately I can't find that email now.

Download Attachment: icon_word.gif Ideal Purple Wire Nuts.doc

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Paul in Austin

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Thanks Mike,

Now, 1 more question. Since the wires are connected by inserting the copper splice and the aluminum branch wire side by side, is this an acceptable method? (see my pics above) All the connections I saw in this condo were made that way.

I noticed the CPSC illustrations have the copper splice coming in at one end and the aluminum branch wire coming in at the other end of the connector. I also did not see any inhibiter or anti oxidant paste. (you could look into the open end of the connector and and see the co/al wires side by side)


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Check this link which shows them done the way you describe.


I don't think it's necessary to use any anti-oxidation paste with these. The purpose of the paste is to prevent the wiring from oxidizing and loosening up. These connectors are crimped into the wire with a hand-held press tool and the connections cannot loosen up like connections that are twisted together or are held by a screw. At least that's my understanding of it.



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Originally posted by Focal Point

I spoke too soon, it is not Undrewriters lab, it was the U.s. Consumer Product Safety Commision.

Here is what I have.


I'm pretty sure I have something from U/L also. I'll keep digging.

Ah, I thought so. CPSC and UL had a bit of a spat over those wire nuts. UL says they're fine, CPSC says they're not.

I like the look of those Alumiconn things you posted. In particular, I like the fact that you don't need a torque screwdriver.

- Jim Katen, Oregon

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I know I'll get flamed for this, but, here goes. I can tell you that the industry standard in this area (Fort Worth/Arlington) was red scotchloks, de-ox and copper wires to pigtail the aluminum. I know from years of personal experience that this was accepted practice by local contractors. I pigtailed the aluminum in my Mom and Dads house in 1978 or 1979 just as I had been taught and had already done a ton of times in other homes (multiply this times other contractors in the area practicing the same application). I've seen the CPCS articles and pictures of burned connectors and I have never seen any negative problems associated with the way we were doing the pigtails.

Flash forward to 2003 and when we remodeled my Moms kitchen I got a first hand look at the pigtailed connections from over twenty years ago in high use areas. So what do you think I found-burned out connections. Nope. Looked like I had spliced them yesterday. This is the most personal connection I have , but, this is a small town and I did this to a bunch of homes. No one has ever called and said, " House burned down. Started in an outlet you "fixed" for me."

I have been a Fireman in my home town (Burleson) and Fort Worth since 1983. I can tell you I have made more fires from copper related bad connections than aluminum. I'm not saying I have not seen scorched aluminum connections that have gotten hot and caused a problem. I 'm saying that I have seen far more copper related problems.

Here is what I beleive to be true.

# 1-Copper is more prevalent than aluminum so I see more copper related problems.

#2- It is still all about the connection and who made them. I do believe a poor aluminum connection will manifest itself sooner than a copper one, but, I think that if all the "improper" pig-tailing in this area was truly the horrible aberration that it is made out to be- we would be burning them down every day and that is simply not the truth.

A poor connection is a poor connection no matter what the material and I think even the "approved" connectors can be improperly installed and cause a problem.

My view from my slice of the world.

Flame suit on!


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Hey Buster,

I've seen plenty of pigtailing the way you described it. I always wrote it up as being wrong, gave them a copy of the CPSC document on AL and sent them to Dan's site. As an HI, that is about all I can do.

There's many times I see things that are "wrong" but are working fine or have worked fine for a long time (2x4 purlins come to mind). I also see a bunch of FPE panels that have no visible signs of trouble. Actually, come to think about it, you could count the ones I've actually seen problems with on one hand and still have enough fingers to pick your nose.

IMHO, just because something is "wrong" according to the powers that be, doesn't mean it's gonna fall down or burn up tomorrow, it means that the odds of something bad happening increase by doing it the "wrong" way.

FWIW, I still see a bunch of late 60's early 70's homes with AL wiring with CU switches and outlets. They haven't burned yet, and they may never, but I think there would be odd makers in Vegas betting on it.

Not flaming you, just throwing some food for thought out there....

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I agree you gotta write it up and tell people about the hazards of aluminum wire connections. I just sometimes wonder about the process that goes on to come up with a decision about accepted versus not accepted. I gotta believe that the people that work at testing agencies are human and so sometimes I think an agenda can get in the way or an outside influence can be exerted. AMP sure wants to sell you an expensive set of equipment to do it "right". Ideal wants to sell purple connectors.

It still goes to the connection and if the testers at CPSC believe that a crimped connection is fool proof, they need to pull their collective head out and see who might be running the crimp tool.

CPSC dropped the ball on FPE years ago,in that,if they are as bad as that small sample seemed to indicate, then CPSC should not have caved to big money and outside influence, they should have demanded a recall or at least done a far more comprehensive and definitive study. That alone has always given me pause when I think about any edict they issue.

So with that in mind I sometimes wonder if the bad connection issue is similar to telling us that a sweetener will cause the Big C and then later it is revealed the lab rat got cancer after consuming the equivalent of 40 lbs of sweetener a day for ten years(I'm exagerating, but, you know what I mean).

I have over the years seen many more associated FPE problems such as fires, smoked equipment and scorched bus bars. The bus bars overheating are almost always related to someone not getting a breaker stabbed right and then having a large continuous load on that breaker. If you only knew how many fires I have been on that started because of an overloaded extension cord. The cord fries and starts a fire. I know a lot of the fires had FPE panels and a breaker did not trip. But I've seen GE, Square D and other brands and if a breaker had tripped there would have been no fire. So was the load enough to trip the breaker or was it cheap extension cords that got hot enough to light off a combustible but not enough amperage overload to trip a breaker? Who knows. If there was a FPE panel I automatically assume it must have been the Federal Breakers but I really don't know.

Donald I read your posts and I always respect what you and a number of other guys on this board have to say about this business and the issues involved, so thanks for letting me rant a little and like you said I'll report it and go on about my business. That's all I can do as a HI.

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