Why so many 2-pole breakers?

[tonype]

Saw this yesterday - all except 3 of the 2-pole breakers appear to be connected to 120-volt circuits power and lighting circuits. Questions:

1. Is this legit?
2. Any idea why it would be connected this way (my 1st instinct was that the home may have been heated electrically, but further investigation did not support this)?
3. Is there a benefit?
4. What, if any problems, can result (nuisance breaker trips)?

http://i15.photobucket.com/albums/a352/TonyPE/IMGP7971_edited-1.jpg

Thanks

 

[Mgraw]

Could they be MWBC?

 

[jumper]

Could they be MWBC?

That would be my guess. I used 2 pole breakers when I ran MWBC in resi to avoid a HO moving the circuit and overloading the neutral.

 

[augie47]

MWBC be my guess also. With the '08 Code change {210.4(B)} you will see a lot more two-pole and 3-pole breakers (or handle ties).
Many of the commercial jobs I've seen lately have gone back to individual neutrals.

 

[Dennis Alwon]

I hate to agree with Gus and the others but I guess I had better.

It is either MWBC or the EC had no single pole breakers on the job.