Cutting lugs to fit needs

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Jminter

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Garland, TX, USA
Current job I'm working on has need of 350 AL one hole lugs, but they are increasingly hard to find right now. We do, however, have on hand some two hole lugs for the same size/material wire. The question is being asked if we can modify the lug by cutting a hole off of the lug to make the 2-holes into a 1-hole. I'm saying no because it's modification of electrical equipment and is no longer listed for that use.
 
I agree with you that it likely violates the listing but it's done every day of the week. Another common occurrence is when the lug hole is too small and it's drilled out. IMO if you cut it and the amount of material that is left on the lug is equivalent to a single hole lug it will not result in an unsafe installation it's just not code compliant.
 
The main concern would be reduced current capacity, arguably.

You can get pin terminations that should allow your conductors to fit available lugs.
 
LarryFine said:
The main concern would be reduced current capacity, arguably.

You can get pin terminations that should allow your conductors to fit available lugs.
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The conductors fit fine. It's a 350 wire into a 350 lug. I don't like the idea of chopping the top half of the lug off to fit the spec calling for one hole lugs.
 
LarryFine said:
I meant as a way to allow using existing 1-hole lugs.

Use a pin to allow the 350 conductor to terminate in the largest 1-hole lug you can find.
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Sounds like he wants to use up the two hole lugs that he already has.

Jminter said:
The conductors fit fine. It's a 350 wire into a 350 lug. I don't like the idea of chopping the top half of the lug off to fit the spec calling for one hole lugs.
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Just out of curiosity what kind of lugs are they?
 
I don't see it as a big deal at all. We cut and strip wire, drill holes in panels, screw things down,,,, stuff gets modified all the time. Besides it's a lug, an inanimate piece of metal stamped out by the thousands from a factory. If you are not reducing the surface area contact of an equivalent one hole lug what is the problem?
 
Arent some lugs coated in some way, and when you cut them or drill them they expose uncoated metal? Is this a concern?
 
FionaZuppa said:
Arent some lugs coated in some way, and when you cut them or drill them they expose uncoated metal? Is this a concern?
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No.
Many lugs are tin-plated in order to minimize issues between dis-similar metals.
In my experience, mechanical lugs tend to be plated after fabrication, while compression lugs are plated before fabrication.
I know that you can see unplated copper on the ends of a tang and inside of the mounting holes on many compression lugs.
 
infinity said:
Since these are compression lugs I would cut one hole off if needed.
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Here doing that would get you wrote up. And if it was a Motorola building it might get you fired.
Especially if The customer caught it before QC did.
 
You described them as “AL lugs”, so that indicates they are mechanical lugs, not compression lugs. One hole mechanical lugs for cable that size usually have a “shoulder” to fit up against a tang and prevent the lug from rotating while tightening or under strain of the cable, especially during a fault. That’s why 2 hole lugs are more typical for large cables. But 2 hole lugs don’t need the anti-rotation shoulder, so by cutting down a 2 hole lug, you are creating a situation that might become dangerous. But it depends a lot on the circumstances of where you are making these terminations.
 
jim dungar said:
No.
Many lugs are tin-plated in order to minimize issues between dis-similar metals.
In my experience, mechanical lugs tend to be plated after fabrication, while compression lugs are plated before fabrication.
I know that you can see unplated copper on the ends of a tang and inside of the mounting holes on many compression lugs.
Click to expand...
??
If you drill the hole bigger you then are placing bare lug metal up against the stud metal, which then as you say, put it back into a disiimilar metal scenario for corrosion to occur. Compression lugs appear to be formed/stamped prior to any coatings as all that I have seen the ID of the holes are plated.

Cutting the compression lug flat to make it shorter exposes the bare metal to whatever environmental air mix there is. Certainly having the coating is better than not having it, yes?

Guess it all depends, but usually the old saying "use the correct thing w/o modification" is the better choice. In a pinch I get it, beyond a pinch, use the right stuff.
 
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