My home has two sets of circuit breakers, one in my apartment, and one in a shared area downstairs (these are switches that pop up with another one or two nearby buttons that also pop open when there is an electrical overload due to too many appliances turned on). Wikipedia states: "circuit breaker: an automatic device for stopping the flow of current in an electric circuit as a safety measure."
So, my question is, why have a circuit breaker upstairs and one downstairs instead of just one?
So, since I'm interested in the wiring inside as home, and voltage inside homes here is fixed (in my case 220-240 V), current equals load. The case would be different if I was considering a circuit where the voltage within the circuit would change with time. Correct me if I'm wrong.