I have only one issue with Checkers explanation. Carbon isn't a conductor, nor is it an insulator. Its a semi-conductor - i.e. it conducts electrical current but not very well. Aside from that his description is spot on.
When designing a circuit the total load current determines the size of the wire, which is over-rated by a safety factor. The circuit breaker is then selected to protect that wire from overload. If a circuit breaker trips, this is due to excess current in the circuit such as to exceed the safety rating of the cable, not the equipment that is being supplied. Re-setting a circuit breaker may trigger an already overheated wire sufficiently to break down the insulation and set fire to surrounding material. You should see the dust and fluff that builds up above the ceilings and behind the sidewalls!
I don't believe that ANY circuit breaker should ever be reset even once, without first determining the reason for it tripping. No circuit that has a circuit breaker is THAT important to safe flight. [But an aircraft electrician is bound to say that, aren't I?
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[Did you know that the main generator wiring on large airliners is unprotected against 'hot' short circuits? The cable is allowed to melt until the hot short no longer exists. That doesn't usually take long and the process is startlingly dramatic!]
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Through difficulties to the cinema