I bought some Alumiconn terminals to connect 3 copper AWG 10 wires (more secure than wire nuts):

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There is corrosion inhibitor paste inside each hole. Amazon product description described it thus: "Ports of connectors contain a layer of corrosion inhibitor that provides resistance from oxidation."

Can these be detrimental to the conduction of the copper (maybe forming insulator layers)?

Also these can be used in all pure copper wires (all of the 3 wires) right?

  • Would they sell it if it screwed up the connection? Electrical parts are some of the most tested and regulated merchandise on the planet, just behind medical devices...
    – dandavis
    Feb 21, 2019 at 16:07
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    After having seen terminal blocks being made of (expletive deleted) pot metal, two wire three prong IEC leads, and other things... I would say that there is a big market in things that screw up connections. Feb 21, 2019 at 17:29
  • AlumiConns are marketed to be used to pigtail aluminum with copper. The purple colored insulation is the color code for this application. The ports are identical, hence one could use them to join copper. But are they reusable? For joining copper conductors I would use WAGO lever connectors. WAGO sell a clear silicone antioxidant joint compound in a convenient squeeze dispenser, but it isn't necessary for copper. AFIK WAGO lever connectors are listed for copper only. Mar 21, 2021 at 0:49

3 Answers 3


It depends on the type of anti oxide compound used, 2 of the 3 types I use are conductive 1 is not. Some folks say it is not needed but most lugs today are aluminum and a little deox on the wires will improve the long life especially if in a coastal region. I recently had to rebuild a panel that had all copper wire with aluminum lugs the lugs showed hot with thermal imaging camera. I removed the conductors and found a large amount of oxide on the lug to wire connection area, cleaned everything up and coated with deox. Let the system run for a day and rechecked it is now running 30°F (17°C) cooler.

  • Is the proper procedure for making the connection of the heavy stranded wire from the meter into the main lugs of the panel to separate the strands and put antioxidant grease between and around the outer strands, then abrade the lugs with the antioxidant grease, then twist or compress the strands together enough to fit the wire into the lugs. Then tighten the lugs hard? to a specific torque? My panel has no grease on this connection that i can see. Guess I need to buy or borrow an infrared imaging thermometer. What voltage should there be between lug and wire with a significant load? Feb 21, 2019 at 22:29
  • Just coating the wires with a thin coat will do but I usually also do the lugs also and the threads of the set screw, in damp or salt conditions the anti oxide paste keeps the threads in good shape, in my case saving multi port large lugs costing over a hundred $ each.
    – Ed Beal
    Feb 22, 2019 at 1:02

The paste inside the AlumiConn does not negatively affect the electrical connection. When the screw is tightened the paste between wire and the metal screw and the metal body of the AlumiConn is squeezed out.

You can use these for copper wires, but it is really unnecessary. In the upper picture the end of the wire is stripped too long. The insulation on the wire is supposed to be inside the skirt of the insulation on the AlumiConn. I think there is a strip gauge on back of the Alumiconn.

EDIT Memory failure! Just looked at my stash of AlumiConns and there's no strip gauge on the insulation.

  • I was just testing them and pulled it a bit when I tried to remove the third wire but didn't have the screwdriver. See imagizer.imageshack.com/img923/8660/ctWiTe.jpg also I just received the Torque screwdriver and the Alumiconn just today from amazon
    – Jtl
    Feb 21, 2019 at 14:02
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    Good answer, but I'd add safety note that if you are going to rely on it to be an insulator, assume it is conductive, and if you are going to rely on it being conductor, assume it's insulator. For example, tighten screws for good contact, do not assume paste would help, but also do not touch paste in the empty receptacle, assume it may be "hot".
    – Mołot
    Feb 21, 2019 at 15:06
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    I assume that none of the various anti-oxidant pastes are conducting. The reason I think so is that the base is a nonconducting silicone grease (earlier ones perhaps petroleum) and so if it were conducting the current would be carried by ions moving in the base oil. At the metallic interface there would be corrosion if there was a current being carried from the metal to the gel. The purpose of the paste is to prevent oxygen from the atmosphere from reaching the reactive surface of aluminum wire or an aluminum fitting. Feb 21, 2019 at 17:51
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    Jim, they may not show conductive with a low voltage ohm meter but checking with a merger some are the clear anti oxide paste I use on 34.5kv lines to my transformers requires non conductive paste , got tapped by An inspector on that one and had to clean the lugs and wires, I did not realize that some were conductive prior to that time .
    – Ed Beal
    Feb 21, 2019 at 19:22
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    I have no specific knowledge about whether these anti-oxidant greases are in fact non-conductive. I was just going on my (elementary) understanding of electro-chemistry. Clearly some greases used to mount devices to heat sinks are designed to conduct heat. I can't imagine any antioxidant joint compound being electrically conductive, but I have no professional expertise in this. Feb 21, 2019 at 21:09

Side note:

Dissimilar metals shall not be joined in a terminal or splicing connector where physical contact occurs between dissimilar conductors such as copper and aluminum, EXCEPT where the device is listed for the purpose and conditions of application. 2018 IRC E3406.8 & 2017 NEC 110.14

I would just check that the device is listed to be used with copper conductors. It probably is, but always good to double check.

  • AlumiConns are marketed to be used to pigtail aluminum with copper. The purple colored insulation is the color code for this application. Mar 21, 2021 at 0:44
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    Also, the "physical contact" issue is utterly moot with AlumiConns anyway, since they are one-wire-per-hole setscrew-type mechanical lug splices Mar 21, 2021 at 2:58

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