2 pole breakers with tie bars

[jwolchko]

I've run into something I've never seen before...
I'm looking at a 3 phase panel with three two pole breakers that are all tied together to feed a sub-panel. I haven't pulled the cover off, I don't have arc flash gear. I need to add another sub-panel to this panel and am trying to figure out what's going on so the I can make a panel schedule and one-line to put in the construction drawings. Why not just put in a single 3 pole 124 Amp breaker? What is the purpose of this?

Just wondering if anyone has seen anything like this and could help me with it. Thanks.

Picture of this on my Google Drive https://drive.google.com/file/d/1Ce-wrt6_z0IAxvmhSKTWxcHucTARDZaF/view?usp=sharing

 

[GoldDigger]

Unless the breaker manufacturer provides it as a tested unit, paralleling of breakers (without a common trip) is not allowed. But if this is just using two poles of each breaker to feed one ungrounded conductor it might be allowed.
Two three-pole breakers with a handle tie would not be allowed for sure.

 

[infinity]

Looks like listed Square D breaker:

https://www.graybar.com/store/en/gb/qob-circuit-breaker-high-interrupting-capacity-89034885#{Mounting%20Type:Bolt%20On%20Mount}&{Interrupting%20Rating:22kA}&{Amps:125A}&{Voltage%20(Volts):120/240%20Vac}&{Brand%20or%20Series:QOB}&{Poles:3-Pole}

 

[jwolchko]

Looks like listed Square D breaker:

https://www.graybar.com/store/en/gb/qob-circuit-breaker-high-interrupting-capacity-89034885#{Mounting%20Type:Bolt%20On%20Mount}&{Interrupting%20Rating:22kA}&{Amps:125A}&{Voltage%20(Volts):120/240%20Vac}&{Brand%20or%20Series:QOB}&{Poles:3-Pole}

OK, Make sense now. It deceived me to think it was something else. THANKS!

 

[jwolchko]

I see now that I wasn't paying attention to the fact that only one of the 2 pole modules was branded and the other two are blank. Feeling embarrassed...

 

[mccabren]

This is the best answer I can find from SQ's website: https://www.se.com/ca/en/faqs/FA100010/

I'm not sure why the two 2-pole breakers in your panel are only rated for 10kA