Crouse - Hines Murry Style MP or MD 200 Amp Main Breaker Difficult to Reset

A 200 amp circuit breaker has a large spring to assist in rapid opening and closing a load of this size to minimize damaging arcing every time is it operated under electrical load

The larger the circuit breaker is and the more poles (1, 2 or 3) that are being opened / closed; the more force it will require to operate - both by hand or when tripping. Compare the tension or force you need to apply to a similar sized circuit breaker at Home Depot, etc.

The troubling issue about this for me is the fact that the 200 amp service disconnect / main is tripping. This is an indication of an overloaded panel / circuit. I usually see individual circuits that trip in a panel - but often find the that main breaker has only 20% - 60% of its rating on it at any given time. If you're tripping a 200 amp service disconnect / main breaker repeatedly - something has got to give - and eventually the circuit breaker will fail. That may be where you are now with this breaker. You may be in need of a service upgrade (if it is the service disconnect) as clearly, you have out grown the 200 amp size one you currently have or need add a new sub-panel to ease the load that this 200 amp main is trying to supply now.

Either way, you should call a reputable electrical contractor to have your service / sub-panel evaluated very soon. Good luck!