What is a "bus stab"??

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tallguy

tallguy

Senior Member
Siemens I-T-E Load Center has the following prohibition regarding tandem breakers:

"SUM OF QT BREAKER RATING IS NOT TO EXCEED 110 AMPS PER BRANCH CIRCUIT BUS STAB."

I'm not familiar with the term "bus stab", asked the master I work with and he had no idea. From the context it sounds like it might refer to the bus on each 120v leg, but I don't want to assume.
 
The part of the buss that is bent out to receive the breakers.

So in this case a pair of 60 amp breakers on the same stab would be a violation
 
iwire said:
The part of the buss that is bent out to receive the breakers.

So in this case a pair of 60 amp breakers on the same stab would be a violation
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Gotcha... Didn't even know that 60/60 tandems existed.

So I can load the thing up with as many QT2020's as I wish... It's at 110A of tandems currently, which had me wondering if I was up against the limit. This makes sense now though.
 
iwire said:
If they did that would be an issue.

Think a pair of 60s opposite each other.
Click to expand...

So the two legs opposite one another constitute one "stab"?

That would make two QT3030's opposite one another prohibited, while QT2020's would be OK. Makes sense.
 
tallguy said:
That would make two QT3030's opposite one another prohibited, while QT2020's would be OK. Makes sense.
Click to expand...

I will take your word for it, we don't get many tandem bolt-ons. :grin:
 
iwire said:
I will take your word for it, we don't get many tandem bolt-ons. :grin:
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I still don't grasp the need for the statement on the panel label, but at least I know what they are talking about now :)
 
tallguy said:
I still don't grasp the need for the statement on the panel label, but at least I know what they are talking about now :)
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I think you only have tandems in your head, ITE won't allow 60a breakers across from each other as well, like Bob has already mentioned...
 
stickboy1375 said:
I think you only have tandems in your head, ITE won't allow 60a breakers across from each other as well, like Bob has already mentioned...
Click to expand...

I don't think so... it only mentions QT, which is the tandems.

Here is an example of a similar Siemens label.
 
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