Not sure if this is ok per code, tap rule, multiple conductors 1 lug

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Aleman

Aleman

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Location
Southern Ca, USA
What we did and this was ok'd by our engineer. This is a industrial control panel, fed from 480V/300A.
We installed 3 14 awg wires into the lugs at top of panel disconnect, along with the feeders. The lugs are not specified for multiple cables. The 14awg is sandwiched behind the
main cables which I believe are size 500, maybe 350. The 14awg's are yellow and run about 1-1/2 feet into a circuit breaker that protects a 24DC supply. I don't believe this to
be exactly ok per NEC multiple conductors in a lug not marked, but on the other hand I believe we have a good connection. This would be also under the tap rule correct?
But ok other than multiple wires on the lug. The yellow wires are colored per UL508A and are marked accordingly.

This is a dual control panel set, one is DC control only and the main has motor drives, contactors etc. The idea is to be able to turn off the 480V to the motor drives and leave power
on the control side.

Any opinions?
 
Aleman said:
What we did and this was ok'd by our engineer. This is a industrial control panel, fed from 480V/300A.
We installed 3 14 awg wires into the lugs at top of panel disconnect, along with the feeders. The lugs are not specified for multiple cables. The 14awg is sandwiched behind the
main cables which I believe are size 500, maybe 350. The 14awg's are yellow and run about 1-1/2 feet into a circuit breaker that protects a 24DC supply. I don't believe this to
be exactly ok per NEC multiple conductors in a lug not marked, but on the other hand I believe we have a good connection. This would be also under the tap rule correct?
But ok other than multiple wires on the lug. The yellow wires are colored per UL508A and are marked accordingly.

This is a dual control panel set, one is DC control only and the main has motor drives, contactors etc. The idea is to be able to turn off the 480V to the motor drives and leave power
on the control side.

Any opinions?
Click to expand...
If the lugs aren't listed for the multiple wire there is a code violation for sure whether it is believed there is a good connection or not.
To try to go beyond that an justify the rest of the installation dos not make the code violation go away.
 
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Some disconnect switches have tapped holes in the lugs or the switch itself for this type of connection. Sometimes you can also add a right angle lug under the screw that holds the lug in place.
 
The 10' tap rule requires conductors with a minimum ampacity of 10% or in this case 30 amps {300 amps * 10% = 30 amps}. If the 10' rule applies the #14 is NG.
 
I looked a bit and didn't see any lugs that would have a hole for size 500 cable and also for something as small as #10. How about ring terminals yellows with 3/8
or 1/2 holes. I kind of hate to put something like that under the lug screws but as far as I can tell that would bring me up to code, as long as I go up to 10 on
my tap wires. Thanks for the advice guys.
 
Aleman said:
I looked a bit and didn't see any lugs that would have a hole for size 500 cable and also for something as small as #10. How about ring terminals yellows with 3/8
or 1/2 holes. I kind of hate to put something like that under the lug screws but as far as I can tell that would bring me up to code, as long as I go up to 10 on
my tap wires. Thanks for the advice guys.
Click to expand...
I don't see an issue with it.
 
Aleman said:
....... The lugs are not specified for multiple cables. The 14awg is sandwiched behind the
.......
Any opinions?
Click to expand...

Disclosure, I am employed by a manufacturer, Thomas & Betts, that makes several brands of terminal and lug products including Sta-Kon terminals and Blackburn, Color-Key and Homac lugs.

The appropriate approval would be is UL486A/B and multiple wire combinations are allowed to be submitted for approval. I have worked with customers who needed multiple wire combinations into a single terminal.

Depending on the terminal brand and wire combination, there may be a UL file number. Checking with the manufacture would be the only way I am away of to confirm if a file exists because this information is not normally requested and not in the general literature.
 
The Terminator said:
Disclosure, I am employed by a manufacturer, Thomas & Betts, that makes several brands of terminal and lug products including Sta-Kon terminals and Blackburn, Color-Key and Homac lugs.

The appropriate approval would be is UL486A/B and multiple wire combinations are allowed to be submitted for approval. I have worked with customers who needed multiple wire combinations into a single terminal.

Depending on the terminal brand and wire combination, there may be a UL file number. Checking with the manufacture would be the only way I am away of to confirm if a file exists because this information is not normally requested and not in the general literature.
Click to expand...

Does this basically mean by special (manufacturer) permission only?
 
I suspect that it might either mean that the fitting was not tested for multiple wires or that the original testing qualified for multiple wires but for some reason the manufacturer chose not to advertise that feature.
In either case, the bottom line would be what documentation the AHJ would be willing to accept. :)

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Those Ilsco's are kind of big but would be perfect for for the job. I don't think I could squeeze them in, not much room between top of cab and
disconnect, plus there is some panduit in there etc. But thanks and I will save the link.

What I did yesterday....Drilled and tapped for 10-32 on the lugs flat area where it wouldn't interfere with any screws etc. Installed #10 with
crimp connectors. Cabinet will be labeled on outside to warn of energized circuit with disconnect off, already labeled on the inside. Maybe I
opened another can of worms but I did this after talking it over with the foreman of one of our electrical contractors. We didn't think 3/8"
ring connectors would hold up well under the main lug bolts.
 
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