Terminal block question

I recently did an inspection in Boulder, CO. When I opened the electrical panel I found an electrician had done some aluminum to copper pigtails in the electrical panel using terminal blocks and wrapped in electrical tape. I was under the impression this requires the purple wire nuts installed properly and called it out in my report. The property owner got a letter from another electrician stating he thought this was safe. The electrician also stated that the purple wirenuts were not longer to be used. I would appreciate and input

Your first mistake.
NEVER make statements specifying anything you are not a Master of!!
You now have nowhere to go except down the Code rabbit hole!!

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I understand and agree with your perspective. Just does not seem proper to have connections taped in a panel so I recommended the owner have an electrician take a look. I did not specify any specific requirements or remedies. The electrician made his statement to the owner after my inspection. The owner then passed this along to me. I am just asking for clarification for my own education.

Okay, with that being said…

What Code cycle and municipality exceptions were at play on the day the modifications were made?

Don’t know?

Welcome to the rabbit hole!!

If you only want a generalized answer, I’ll defer to the Sparkies that frequent the MB from time to time.
I won’t take the liability for any misquotes or misstatements that may occur and bring harm to your business.

Sorry… not sorry.


Who hired the electrician?

Was this the same electrician who did the original install?

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Sounds like a “Brewski Bandit” to me!!

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I do not believe it was the same electrician that did the pigtails. I know the owner was searching for an electrician to come out

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Cool, you elevated a potential issue to a licensed professional. It all worked out.

Your a generalist, don’t sweat it.

I bet there is more than one acceptable way to pigtail AL wire. We’ll see.


Appreciate the responses. I will post an update if I get a definitive answer from a pro sparky

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Is the objection to the splice or the tape?

Splices are allowed in panels.

Splices that carry current need to be insulated.

Is that aluminum or tinned copper?

I understand splices are allowed. I was under the impression pigtails between copper & actual aluminum needed to use specific wirenuts. So, when I saw connections wrapped in electrical tape it raised a flag.

I just talked to an electrician I really trust and he let me know this is acceptable. It is often used when the wires are not long enough to use wirenuts.

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Those terminal blocks do not allow the dissimilar metal to touch. There are other connectors that are approved for use with AL. Any connector needs to be listed for the intended use.

As Jim stated, the blocks should be ok, as long as the copper and aluminum are not touching, and as long as it is insulated. But here is a little more clarification since you are asking for your own education… Whenever you have copper and aluminum together, the individual conductors should be held down under a screw terminal, and not allowed to move. That is the problem with copper and aluminum conductors touching, or being twisted together under a wirenut. They expand/contract at different rates, and this is what leads to fire hazards, because they start to work loose from each other and arc.
That is also why the purple wire nuts are no longer recommended. All aluminum wiring remediation should be done with alumicon or other connectors that basically use the same concept. (screw terminals)


I recommend watching this entire video just for the general information especially if weak on electric with AL use, or jump directly to the 11:30 mark for relevance to this thread.

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The Ideal No. 65 is the least desirable connection for this and not allowed by many AHJs because the CPSC has ruled them as unsafe. My understanding is that all the AHJs in the Denver metro no longer allow purple wire nuts, but of course, you can buy all you want at Home Depot.


Got a link to that?

Here is a publication on the topic. Kinda interesting that in their example, they recommend against all twist-on connectors, but their photo shows common twist connectors.

CPSC Publication 516 - Repairing Aluminum Wiring (cpsc-d8-media-prod.s3.amazonaws.com)


I believe there is a (UL?) rated crimp connector, but someone else can expound on that aspect. Good info on the purple caps being no bueno, at least there is no certifying body that approves them, at least from what I have read.

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Got ya, thanks. I thought maybe there was something new that I missed. I saved that one when it came out 10 years ago, but a good read for the newbies and those that missed it.