In fairness to this situation ...
I have seen several similar installations. In each case, the equipment - usually an ordinary breaker panel, sometimes a motor starter enclosure with overload elements - was in an area where there was something else applying heat to the panel. For example, a nearby oven. This higher ambient resulted in false tripping, and the open cabinet / fan was a solution to that problem.
Mind you, I'm not defending the practice! It's just that you need to understand what the cause of the problem is, before you can try to fix it.
Even where allowed by the code, I try not to solve problems by using a larger breaker / fuse. Doing so seems to 'teach' the uninformed that big fuses are OK ... when that's not the case at all!
Mike, as to all that exposed stuff in the cabinet ... this is very common in equipment of that age. That panel was probably built before WW2.
Fuses such as these are often changed 'hot,' with the load disconnected. That's why we have fuse pullers!
Then again, some understand current rules to require locking out a breaker before changing a light bulb. Just goes to show you how much times have changed ....
(After all ... remember when ashtrays and lighters were common promotional give-aways?)
