Wherever electricity has to be distributed in low-voltage networks, circuit breakers regulate which power supply units remain in operation in the event of a short circuit. Sophisticated mechanics are required to ensure that these switches work reliably. Jörg-Uwe Dahl works for the 'Energy Management' division in Berlin and has, for example, invented a switch with a space-saving rotor that makes reliable contacts with very low current loss and is more robust than previous models.