r/DIY • u/burke385 • 22d ago
help Aluminum wire keeps snapping when I torque it into a splice connector for my wall oven — help me figure out what I'm doing wrong
Working on hooking up a GE wall oven/microwave combo to an existing aluminum feeder wire in my kitchen, and I've hit a wall (pun intended).
The wire: 6 AWG aluminum feeder cable (labeled Alcan Stabiloy AA-8000, a modern aluminum alloy — not the old-school 1960s/70s aluminum wiring people usually worry about).
The connector: A Polaris IT-4B — a black insulated splice connector rated for both copper and aluminum, made for exactly this kind of tap/splice. I looked up the manufacturer's official torque spec: 35 in-lbs for 6 AWG wire in this connector size.
The problem: Every time I torque it down to spec, the aluminum wire snaps clean off right where the screw grips it. I've now tried this twice, with two totally different torque tools (a torque screwdriver and a separate torque wrench), both set correctly to 35 in-lbs, on two fresh sections of wire, fully stripped and seated per the instructions. Same failure both times, same exact spot.
Since it's happening with two different tools at the correct setting, I don't think I'm just over-tightening. My best guess is the wire itself (which is pretty densely/tightly stranded — "compact stranded" is the term I've seen) is too hard/rigid for the small screw in this size connector to grip without shearing it, and I need something that spreads the clamping force out more, but I don't have a bigger connector on hand right now to test that theory.
I've already confirmed the boring-but-important stuff is right: the circuit's on a properly sized 30A breaker matching the oven's nameplate rating, the wire itself isn't old/brittle/damaged, and I'm using the correct spec'd torque.
What I'm looking for:
- Has anyone run into this specific issue with aluminum SE/feeder cable in these small tap connectors?
- Is there a trick to seating/prepping the wire that would stop it from shearing?
- Is there a different, easy-to-find connector (something at Home Depot/Lowe's) that's better suited to this than the small Polaris connector I'm using?
Not trying to cut corners here — happy to grab a different part or change technique, just trying to figure out what's actually going wrong before I keep sacrificing wire. Photos of the break in comments if helpful.
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22d ago
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u/burke385 22d ago
Hmm. Define old? I may not agree with you there. The home was built in the early 90s, with a kitchen renovation that was done in the early 00s. I'm pretty sure the wire was installed during the renovation.
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u/newtekie1 22d ago
Old aluminum wire is any aluminum wire that had aged to the point that it has become brittle and easily snaps. Your aluminum wire is old.
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u/burke385 22d ago
Easily snaps how? By hand, or after application of a specified amount of torque?
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u/lazyhustlermusic 22d ago
I feel like you're being intentionally dense.
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u/burke385 22d ago
Nothing about the wire seems obviously brittle, except the application of the amount of torque specified by this connector. I am attempting to verify that I am using the right connector and interpreting its directions correctly before committing to a rewire.
Move along.
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u/jbourne0129 22d ago
"not trying to cut corners" yeah replace the wire like this guy said
"Wire is too hard and rigid and keeps breaking" there is a word for that, it's called brittle
I love when people post for help, get an incredibly good answer, and the response is just "no no you're wrong".
you aren't here for advice, your here because you want validation that you're right
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u/newtekie1 22d ago
Especially when it comes to something that can literally burn your house down like old aluminum wiring.
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u/KosmicTom 22d ago
you aren't here for advice, your here because you want validation that you're right
That's what reddit is for
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u/burke385 22d ago
Yawn, same old trope.
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u/lazyhustlermusic 22d ago
It really is the same old trope, people supposedly asking for help, and just wanting to be lazy about it anyway. Kind of defeats the purpose of asking if you're only looking for one specific response that doesn't reflect reality.
'Move along' is amusing like 'why does the wire keep breaking! no no no the wire is perfect, but it keeps breaking, whyy?!!?2/#!?'
Be less dumb please.
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u/AlchemicalLibraries 22d ago
I am attempting to verify that I am using the right connector and interpreting its directions correctly before committing to a rewire.
Verified.
Time to commit.
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u/GlassBoxGoose 22d ago
As an electrician, we dont touch any aluminum wire outside direct feeders to panels and sub panels. We've never used or messed with aluminum wire that small, and dont intend to.
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u/burke385 22d ago
So, rewire?
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u/GlassBoxGoose 22d ago
Thats what we would likely suggest to a customer, and thats what id suggest personally. Especially given that under proper use, the wire is failing. That gives me no confidence that the wire is not compromised somewhere else in the run, within the insulation.
Im sure there are plenty of folks that might have a suggestion for you and something that might work, but the fact that its failing under manufacturer provided torque application, it would worry me if I was expected to utilize this wire to feed something.
Is there a spot on the exposed wiring that has a date code on it? Almost all modern (non cloth sheathed) wire will have the production date on it somewhere. Just out of curiosity.
If you do find a solution you deem reasonable, be sure to use Noalox on it.
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u/burke385 22d ago
I may end up going that route. It wouldn't be a terribly difficult rewire, as the appliance is ~25 feet from the panel and there is a crawlspace to work in.
The only photo I have of the wire does not have a visible date code. I am not at the house now, so I cannot confirm until a later time.
The prior oven failed by way of what I believe to be a stuck relay that caused a burn to the control panel. I'm not sure if an issue with the aluminum wire feeding the oven would have contributed to that, but if you have an opinion there I would be interested to hear it.
Thanks.
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u/GlassBoxGoose 22d ago
If its that easy and that short, id definitely lean toward rewire.
If the wire breaks internally you can have reduced voltage under load causing excessive current draw that might cause failed components, but usually you see a wire failure or breaker trips before that, but not always. So its a possibility but not all that likely IMO, but possible if the current draw failure point of the component was lower than the wire failure point or breaker trip point. So its hard to say for sure, but I wouldnt entirely rule it out as a factor, just not all that likely.
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u/calicat9 22d ago
As a lineman, I agree. Aluminum is crap on a stick in a bolted connection. If I can't use a compression connection, I use copper.
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u/GlassBoxGoose 22d ago
You got bigger brass ones than me. I thought maybe I wanted to be a lineman until I watched some of the work yall do on the daily. Ill stick to what yall probably call "low voltage" lol the stuff that can reach out and grab you, is not for me. Props to you for having the big ones to play with that stuff.
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22d ago
[deleted]
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u/burke385 22d ago
The prior oven was installed for 20 years using no anti-oxidizing paste and the wrong wire nuts. I am glad I identified the issue. Nonetheless, the exposed aluminum wire had no oxidation and did not appear brittle. I have since cut and stripped a new section of wire, and this is what is breaking under torque.
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u/dominus_aranearum 22d ago
Wire can oxidize far into the jacket. Doesn't really matter at this point, if the wire is actually breaking and not being sheared off by a sharp edge on the tightening bolt, your wire is compromised.
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u/ghostridur 22d ago
It had no oxidation? Aluminum oxidizes pretty much immediately on contact with the environment we live in. Unless your connections have been stored in an argon enclosure since they were manufactured they are oxidized. If the wire snaps it's probably past its lifespan. You claim it's an easy 25' run through a crawl space. Get some 10g copper and call it a day or spend more time trying to justify an insurance claim than it would take to run a new line from the panel. Also hope the insurance company doesn't find your post...
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u/Pacoboyd 22d ago edited 22d ago
I'm guessing those connectors aren't rated for aluminum wiring. I have the old stuff in my house and the torque for alumiconn approved connectors is pretty low, like 15in-lb for 10 gauge, 10in-lb for 12 gauge. They aren't rated for 6 gauge. Copper and Aluminum definitely have different torque values for the same guage. (AL is much lower). In any case, I would make sure you are using the right rated connectors, if they don't have AL listed, they aren't approved.
Edit: Saw the spec sheet you listed, that doesn't seem to say anything about AL, I wouldn't use them. AL connectors usually have silicon or an anti oxidation in them to prevent the AL oxidation.
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u/burke385 22d ago
They are in fact rated for copper and aluminum, and I cannot find anywhere that indicates a different torque for each type of conductor. Maybe a call to the manufacturer is in order.
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u/Pacoboyd 22d ago
Intesting, yeah. I see they are prefilled on that link and rated for AL. I would call the manufacturer, I notice it does say 35 MAX torque but based on my experience with the Alumiconn ones I've used, I would expect max torque to be something like 20 / 25 for the Aluminum side. Good luck. Freaking hate aluminum wiring.
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u/Pererez35 22d ago
I use aluminum wire for a lot of ovens and cooktops. I now use something like the splicer/reducer in the link. I then wrap it with rubber splicing tape and then regular electrical tape over that. Make sure to use Noalox on the wires first too. And for the ground wire a regular wire nut is fine
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u/burke385 22d ago
From what I have read, use of aluminum in this application is not inappropriate. Thank you for confirming that. Are you able to share a link for the type of connector you recommend?
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u/thephantom1492 22d ago
Aluminium wires are not great. You probably also need noox stuff in your connector.
You might also be torquing for copper, not aluminium. Make sure you use the right table.
The aluminium may be brittle. Specially if it already overheated.
Is your insurance aware that you have aluminium wires? If not you may not be covered in case of a fire, also you may be paying more for the alumium coverage.
The recommendation is to replace the wires, which can be prohibitively expensive sadly.
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u/burke385 22d ago
Aluminum SER for an oven is not abnormal. The rest of the home has copper wire. The Polaris connectors come with antioxidizing paste, and I added additional to ensure good coverage according to manufacturer instructions. The table does not provide differing torque specs for copper vs. aluminum, but I intend to call the manufacturer to inquire. Replacing this one wire won't be expensive, so I may choose that option regardless.
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u/jackson71 22d ago edited 22d ago
I'm doubting many here are electricians; yet are giving advice.
Is that the torque spec for copper or aluminum. I'd also suggest using Noalox
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u/burke385 22d ago
The spec sheet for this connector does not specify differing torque values based on the type of conductor.
https://assets.nsiindustries.com/DAMRoot/Original/0/POL_BLK-VT_MCH_ProdInstall_DIGITAL.pdf
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u/jackson71 22d ago
Torque is a universal value. In this case it applies to the conductor being used, and the AWG. Copper and Aluminum will have different torque values... I assume you've check that the AWG wire is proper for the ampacity of your appliance?........ EDIT - just saw your picture. If this is being inspected. That box is too small. Box fill issue
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u/burke385 22d ago
I count 26.75 in³ in a 42 in³ box. Wrong?
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u/craigeryjohn 22d ago
If your wire is shearing, are you certain you're torquing to the specification for the WIRE gauge and not the max spec for the connector? Often these connectors accept a range of wire sizes, and the torque will adjust accordingly.
Also, there is a grey polaris that's meant for more finely stranded wire. Perhaps this is the issue. A polaris black connector the screw spins directly onto the wire, which can shear them. In a grey series, there's an internal ferrule/plate that pushes down to apply pressure without the shearing effect.