This job was to replace an old power-board with a new circuit-breaker board.
Circuit breakers are automatic protection devices in the fusebox that switch off a circuit if they detect a fault. They are similar in size to fuses, but give more precise protection. When they ‘trip’, you can simply reset the switch. But make sure you correct the fault first.
I pride myself on my efficient, tidy and safe work, as witness the professional and neat wiring here.