How many crimp lugs can be stacked on a stud?

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dpslusser

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How many crimped on lugs can be stacked on a single stud? If I have a stud that is 2 inches high and I use stacking lugs, with jam nuts I could get more than 2. I have only ever seen 2 lugs on a stud and was wondering if there is a rule about it. See the picture below.

Marathon-Power-Stud-Blocks.jpg
 
Provided there is enough clearance, you can get 4 lugs on a stud without bending or otherwise modifying them to fit. Two standard, two offset, one matched set inverted.

AFAIK, there is no restriction on doing this as long each conductor is a member of the same circuit.
 
As Smart stated if you get the right combination of lugs you can stack many on the same stud. Here's 10-500's on the neutral, if you look closely 4 of those might fit on one side if the studs are long enough.

20080209_65.JPG
 
Thanks for the help guys.

I haven't done alot of control panel design and layout which contains such high current. This current job is a 5 door enclosure with a 1200 amp feeder for 10 VFD's.

Thanks!
 
dpslusser said:
Thanks for the help guys.

I haven't done alot of control panel design and layout which contains such high current. This current job is a 5 door enclosure with a 1200 amp feeder for 10 VFD's.

Thanks!
Click to expand...
I will give you a hint. It is sometimes more cost effective to buy a 3 pole MCCB and use it as a distribution block than it is to buy a distribution block. There are distribution lugs available for many common MCCB that allow you to tap right off the lug.

This is especially true if you need a relative high SCCR.
 
Ya, I got pretty good pricing on the breaker but list price on the Spreader Terminals is insane. 3,000 dollars for 3 pieces of metal.

Do you guys have suggestion for another manufacturer?
 
Have any of you guys used something like Erico's Flexibar?

7Lwyskxen5_1351214738.jpg456755.jpg

This looks like it would be an awesome product to use in tight areas when building panels.

Is there more manufactures than Erico?

Can anyone chime in on how it is to work with?

Thanks,
Dave
 
dpslusser said:
Ya, I got pretty good pricing on the breaker but list price on the Spreader Terminals is insane. 3,000 dollars for 3 pieces of metal.

Do you guys have suggestion for another manufacturer?
Click to expand...

It is entirely dependent on the deal(s) your company makes with their suppliers. Some companies are relatively good at making such deals, and others a lot less so.
 
dpslusser said:
Have any of you guys used something like Erico's Flexibar?

View attachment 10993View attachment 10994

This looks like it would be an awesome product to use in tight areas when building panels.

Is there more manufactures than Erico?

Can anyone chime in on how it is to work with?

Thanks,
Dave
Click to expand...

I have looked at it pretty close. UL508a does not allow you to use the ampacity values that Erico claims. You are limited to the 75 deg C column of table 28.1. Flexibar is very expensive copper. In fact, the only reason you can use it in a UL508a panel is that it is dual rated as AWM. UL has advised me that we mgiht be able to use some of the extended ratings in a UL508a panel but it would require a change in our procedure.

I have found that often by physical arrangement I can use larger wires without all that much trouble. One "trick" is to use bottom fed MCCB where it is helpful. especially helpful with VFDs where the power feed comes in at the bottom. The MCCB can be located under the VFD and power fed from the bottom up.

be careful as not all MCCB are available where they can be bottom fed.
 
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