Wire through mechanical lug

[PaulEd]

I want to know if this is legal. I’ve heard that you can’t run a wire, THHN, or similar directly through a mechanical lug as it’s not rated for it? Should this slug be an open type lug or is it OK to run this wire through the mechanical lug like this?

 

[PaulEd]

I can’t attach a photo for some reason

 

[ptonsparky]

I've done it before, doesn't mean it's correct. Depends on what you want to do.
Lay in lugs, common on the larger grounding bushings, absolutely. One conductor bonds all the raceways together and to the enclosure.

I use Screen Snip for quick attachments.

 

[petersonra]

I want to know if this is legal. I’ve heard that you can’t run a wire, THHN, or similar directly through a mechanical lug as it’s not rated for it? Should this slug be an open type lug or is it OK to run this wire through the mechanical lug like this?

The UL listing determines what kind of wire can be used with a lug. THHN is a type of insulation so it's doubtful it matters much. Some mechanical lugs are not listed for fine stranded wires but generally THHN is not fine stranded.

 

[PaulEd]

The UL listing determines what kind of wire can be used with a lug. THHN is a type of insulation so it's doubtful it matters much. Some mechanical lugs are not listed for fine stranded wires but generally THHN is not fine stranded.

Thanks

I wish I could upload a picture lol

I know that the THHN is the issue but can the wire run through a mechanical lug (over the bolt infact that attaches the mechanical lug to the transformer casing) and then terminate to the xo? Doesn’t seem that that’s what the lug is designed for.

How does one find out what a product is listed for or not?

 

[infinity]

The terminal is probably not listed for a pass through but IMO it won't really effect the performance.

 

[PaulEd]

The terminal is probably not listed for a pass through but IMO it won't really effect the performance.

Agreed. Thanks

 

[Little Bill]

The terminal is probably not listed for a pass through but IMO it won't really effect the performance.

I don't see the difference between connected and pass through. I see that often on the neutral in meters.

 

[LarryFine]

I wish I could upload a picture lol

Where is the pic now? We can tell you what to do.

 

[PaulEd]

Where is the pic now? We can tell you what to do.

I can’t figure how to upload it.

 

[PaulEd]

I don't see the difference between connected and pass through. I see that often on the neutral in meters.

right but it may be different than other mechanical lugs specifically designed to do so? unsure

 

[petersonra]

right but it may be different than other mechanical lugs specifically designed to do so? unsure

If it does not say you can't do it, it is probably ok.

 

[PaulEd]

If it does not say you can't do it, it is probably ok.

Where does somebody look up this information? I’ve never been the kind of person that could find what an item is listed for and what it’s not listed for. Is it just on the directions? And it’s only allowed to do things as permissible in the instructions? That part of our business really confuses me.

 

[Fred B]

I know that the THHN is the issue but can the wire run through a mechanical lug (over the bolt infact that attaches the mechanical lug to the transformer casing) and then terminate to the xo? Doesn’t seem that that’s what the lug is designed for.

What is the THHN conductor used for? Are you adding to an existing system?
Is this THHN your GEC? If so the best way is the Bonding termination like shown in the bottom of the picture. Second option would be a lay-in lug, Like others said, I don't think the solid terminal lugs would allow for a "pass through" of the conductor as the attachment bolt would be interfered with by the conductor or can damage the conductor, The picture below show termination lugs I think look like what you are describing.

Is the THHN your Neutral (grounded) conductor? Not sure why you are not adding a mechanical lug that accepts more than one termination like shown on this transformer then simply drop your GEC/bonding conductor to the case:

 

[electrofelon]

Where does somebody look up this information? I’ve never been the kind of person that could find what an item is listed for and what it’s not listed for. Is it just on the directions? And it’s only allowed to do things as permissible in the instructions? That part of our business really confuses me.

Maybe the UL white book?

UL Listing/White Book

How do I find the UL listing or is it the White Book for electrical equipment? I requested a White Book from UL a number of years ago and they just mailed it out to me for free. It's about the size of the NEC, but much more difficult to actually find what you want in it. :blink:

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