schotchlok type "R" rated for alum connections??

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rt66electric

Senior Member
Location
Oklahoma
I recently rewired a small burn-out apt. I almost balked when I found all of the original wiring was aluminum. The facilities "electirician" told me to get alum wirenuts at a certain old school supply house. They sold me a "OLD" bag of type "R" red schothloks, the lable read ALUM-to-ALUM or ALUM-to-COPPER, or copper-to copper, UL listed, for $55 a bag of 500. I thought maybee a found a better alternative to purple nurples??? I found a newer box of type"R" and the label was not rated for ALUM ????? HEY-WHATs-THE-DEAL ???? I busted open a sample of both lots, and the innards appeared the same, a spring inside a small lead-head.
 

macmikeman

Senior Member
When those places were wired there was no such thing as an Ideal 65 wirenut or any of the other "listed" methods found nowadays. Those Scotch wirenuts were what they used then. If left untampered with, most of the old connections are usually still pretty good. Once somebody comes along who shouldn't be touching any wiring, and adds a copper wire or two into the splice- watch out.....
 

rt66electric

Senior Member
Location
Oklahoma
suitable alum connectors?

suitable alum connectors?

I'm guessing you and I have different definitions of "rewired".

For clarification I pulled out all alum where possible and replace w/copper from breaker to device.
For future projects-
My question is whether the TYPE "R" schotchloks are suitable for alum/alum or alum/copper connections ?? The older label says suitable.
 

macmikeman

Senior Member
My question is whether the TYPE "R" schotchloks are suitable for alum/alum or alum/copper connections ?? The older label says suitable.

I'll re-explain. When they first started using alum. romex, they didn't know that they had a problem yet. Scotch R connectors were "ok" to use at that time, but it was before a bunch of lawsuits. They do not have a listing for aluminum at this time as far as I know.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
My question is whether the TYPE "R" schotchloks are suitable for alum/alum or alum/copper connections ?? The older label says suitable.
The key piece of history that applies to the answer to your question is this: Around 1989 UL quietly stiffened the requirements that wirenuts had to pass. Specifically, the requirements pertaining to Aluminum conductors was stiffened. Wirenut manufacturers quietly dropped the Aluminum capability.

For most of the next decade the only pressure connector capable of splicing Al-Al and Al-Cu was the COPALUM Safety Connector, then made by AMP, .

Wirenuts manufactured under the new 1989 standards are simply rated for Cu-Cu only.

Now, the R Scotchlok that I hold in my hand, pre 1989 to post 1989 is essentially the same, except for the listing. But it is the listing that makes it "legal" for certain uses, and not for others.

When I researched this question back in 1990, a UL representative explained to me that all the "old" product, the product stamped Al-Cu, was still legal for Al-Cu splices. This same UL rep explained that the old product would eventually be off the warehouse shelves, and that would be the end of the capability of 3M R Scotchloks to splice Al and Cu. He guessed that would take about ten years. You've just demonstrated that it's approaching twenty years.
 

B4T

Senior Member
One more thing.. the Ideal Purples are not rated for AL - AL connections.. when pigtailing you run into the neutrals with 35 year old wire nuts on them.
 
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