Parallel Circuit Breakers

Sure

Then set up a hot dog stand to sell refreshments to the people watching the flames

What voltage and rating are the breakers? It can be done but only with the correct protection.

No, you can not do it by yourself, but it is allowed to be assembled in factory where the system undergoes all sort of testing . Here is the quote from the NEC regarding the use of fuses or Circuit Breakers in parallel:

"240.8 Fuses or Circuit Breakers in Parallel. Fuses and circuit breakers shall be permitted to be connected in parallel where they are factory assembled in parallel and listed as a unit. Individual fuses, circuit breakers, or combinations thereof shall not otherwise be connected in parallel."

- MS

Short answer no, long answer - almost always no. There are some cases where parallel circuit breakers can be used when linking different sources together, but NEVER two circuit breakers in parallel on the same source!

The same goes for fuses if you were wondering.

I have a photo that I wanted to post,but can't find it at the moment. It shows a 3P 63A MCB with all 3 poles commoned together at each end, functioning as the protection device for a DC power system.

If I hadn't seen it done, I would have said NO , you can't do that. Actually, at the time I did say NO, and the DC power systems engineer that I was discussing this with said 'You may not be allowed to do this in an AC system, but we do it all the time to protect DC power systems'.

Just because you CAN doesn't mean you SHOULD.

If you do that with lets say a 30A 3P breaker, the sensing elements are still 30A. As soon as ANY ONE pole hits 30A it would trip. So you did not really make a 90A breaker, you made a 30A breaker with redundant power paths.

In mathemetics 2 plus 2 makes four but not in the electrical world.

Any two CB's, no matter from the same manufacturer of same or dfferent ratings have fractionally different time of operation, fault sensors inbuilt have difference in magnitude of trigger sensing and upto 15% is standard deviation.

Take into account short circuit tripping, the comparatively long time delay in circuit opening by one of the two will cause symmetric faults to be unsymmetric, duration of first current peak will be prolonged causing the system to yield, the time deviation will also cause travelling surges of unusual proportion for the whole system protections to be in jeoperdy.

To fulfill your ambition I suggest you join a manufacturer whereby at the test bench you can pluck 2 components from a whole lot to be of coincidal symmetrical characterstics to work in parallel.