NEC 2011 finely stranded cable vs UL for OEM??

[al in wi]

I am a bit unsure on how to proceed with this inquiry, any assistance would be very much welcomed.

The 2011NEC now specifically requires that termination lugs used with finely stranded cable should be listed/marke for such use. This eliminates 99% of all mechanical lugs. I believe there is one mechanical lug that is allowed (Greaves P-type clamp).

This is not a problem for me until we opened up the alternator/terminal cabinet of a generator with a factory installed 400A breaker. The breaker has mechanical line lugs and the cable from the alternator is finely stranded. The cable ends are stripped and wrapped in copper tape before they inserted in the mechanical lug. Are they in violation of NEC? Are they even bound by NEC?

NEC defines their coverage downstream from the service point, ART 90.2 (A). Does this allow the manufacturer to claim that the breaker is behind the service point and is not bound by NEC? Rather they are bound by UL listing/testing of the equipment as a whole.

Any help in clarifying? I am also looking for source references.

There is a Square D whitepaper saying that it is normal practice for OEM to use copper wrapped cables into mechanical lugs. i am assuming if you open up a SQD switchboard or MCC with direct connect device, they do use this procedure to tap onto the horizontal bus. Are they claiming the same thing "what is manufactured inside the device is not covered by NEC"? as NEC only covers the installation of such devices.

sorry for the long winded narration....just wanted to convey all my thoughts as i solicit yours

 

[Cavie]

This is not a NEC issue. It is a UL listed assembly.

 

[kwired]

This is not a NEC issue. It is a UL listed assembly.

My vote goes here also.

 

[buzzbar]

My opinion is that the copper foil wrapped fine strand wire complies with the code. Besides a crimp-on connector, you can also slip a bare ferrule like the ones made by Burndy:

http://www.burndy.com/uploads/pdf/unins_ferrules_cutsheet.pdf

I was told by an inspector that regular mechanical lugs aren't accepted because the fine strands can break as you tighten the lug. The only type that will work are lugs with 'pressure plates'. Many breakers have the pressure plate type lugs built in.

 

[al in wi]

thanks...
and i agree, the copper wrapped finely stranded lugs meet the "spirit" of the code, but the2011NEC specifically calls out against this practice. They want the lugs be marked and UL listed for finely stranded cables. So we are are going to compression lugs and we are also going to consider using sleaves and ferrules.

however, they are looking at existing/past shipments.

Although I agree that this is a UL issue (not NEC), Is there any other references on what differentiate the two coverage? Local AHJ is thinking that the line-side termination (Gen terminal to lineside cb lugs), is covered by the NEC.

I am seeing some ground work as they establish their arguments.
I need to do some ground work also to establish our argument.

 

[jim dungar]

Be aware that you have lugs and you have terminations, they are not the same thing.

As an OEM when you install a conductor into a lug and then submit that assembly to UL, what you get back is a device with a 'listed termination'. UL then allows you to provide a lug and the proper instructions so that a field installed conductor maintains the 'listing' for the termination.

 

[templdl]

I am a bit unsure on how to proceed with this inquiry, any assistance would be very much welcomed.

The 2011NEC now specifically requires that termination lugs used with finely stranded cable should be listed/marke for such use. This eliminates 99% of all mechanical lugs. I believe there is one mechanical lug that is allowed (Greaves P-type clamp).

This is not a problem for me until we opened up the alternator/terminal cabinet of a generator with a factory installed 400A breaker. The breaker has mechanical line lugs and the cable from the alternator is finely stranded. The cable ends are stripped and wrapped in copper tape before they inserted in the mechanical lug. Are they in violation of NEC? Are they even bound by NEC?

NEC defines their coverage downstream from the service point, ART 90.2 (A). Does this allow the manufacturer to claim that the breaker is behind the service point and is not bound by NEC? Rather they are bound by UL listing/testing of the equipment as a whole.

Any help in clarifying? I am also looking for source references.

There is a Square D whitepaper saying that it is normal practice for OEM to use copper wrapped cables into mechanical lugs. i am assuming if you open up a SQD switchboard or MCC with direct connect device, they do use this procedure to tap onto the horizontal bus. Are they claiming the same thing "what is manufactured inside the device is not covered by NEC"? as NEC only covers the installation of such devices.

sorry for the long winded narration....just wanted to convey all my thoughts as i solicit yours

While assigned as an breaker application engineer one of the things that peaked my curiosity was the the various types of wire that were available and the mechanical lugs that are normally supplied with breakers, contactors, and starters. It was easy to establish that the mechanical lugs were UL486 listed. But thne I had to follow the rabbet trail from there.
In very basic terms UL486 involves a heat rise and pull test. The actual wire is limited to building wire, 7, 19 strand to4/0, 37 strand to 500MCM, 61 strand 600MCM and above. This does not include wire such as Hypalon. One of my drive OEMs was using Hypalon to terminal pnmy breakers an ended up frying a 250a frame. I also caught one of my overhead crane manufacturers doing the same thing and it was wire education time for both. Wiresw such as HYpalon can not be torqued enough to compress the inner most strands of wires which will lead to a failure.

I was going to include a copy of what UL486 covers but you can just as well google it.
But I did include a copy of a wire size table from the south wire catalog as and example of wire sizes and stranding that would be allowed to be used with UL486 listed mechanical lugs.

 

[templdl]

While assigned as an breaker application engineer one of the things that peaked my curiosity was the the various types of wire that were available and the mechanical lugs that are normally supplied with breakers, contactors, and starters. It was easy to establish that the mechanical lugs were UL486 listed. But thne I had to follow the rabbet trail from there.
In very basic terms UL486 involves a heat rise and pull test. The actual wire is limited to building wire, 7, 19 strand to4/0, 37 strand to 500MCM, 61 strand 600MCM and above. This does not include wire such as Hypalon. One of my drive OEMs was using Hypalon to terminal pnmy breakers an ended up frying a 250a frame. I also caught one of my overhead crane manufacturers doing the same thing and it was wire education time for both. Wiresw such as HYpalon can not be torqued enough to compress the inner most strands of wires which will lead to a failure.

I was going to include a copy of what UL486 covers but you can just as well google it.
But I did include a copy of a wire size table from the south wire catalog as and example of wire sizes and stranding that would be allowed to be used with UL486 listed mechanical lugs.

This is the wire size table that I failed to attached in my previous post regarding stranding.
What need to be done when using that fine stranded wire such as Hypalon os to remove the mechanical lugs entire lug and then terminal the wire with crimp on ring tongue type terminal and bolt the connections. Caution should be used in the type of material that the fasteners are made of as they will most likely in the current path which can cause heating to take place. Some breaker manufactures do had special nuts available for use with their breakers.

 

[don_resqcapt19]

...
What need to be done when using that fine stranded wire such as Hypalon is to remove the mechanical lugs entire lug and then terminal the wire with crimp on ring tongue type terminal and bolt the connections. ...

Even with the crimp on terminal, they still have to be listed for use with the fine stranded conductors. Some standard crimp connectors are listed for both the standard and the fine strand conductors, but many are only listed for use with the standard conductors.

 

[templdl]

Even with the crimp on terminal, they still have to be listed for use with the fine stranded conductors. Some standard crimp connectors are listed for both the standard and the fine strand conductors, but many are only listed for use with the standard conductors.

Good point Don.
Being that my experience has been limited to devices that are supplied with mechanical lugs I understand the application of ring tongue terminal but I am not familiar with how they a listed with wire/cable types.
As with mechanical lugs sometimes it's difficult to find this information.