The selective main circuit breakers (HS91) can be operated by laymen and are designed for the highest overvoltage category. The application area is diverse: as a disconnecting device at the meter station in accordance with the network operator's TAB or VDE-AR-N 4101 as well as in all low-voltage main distributions to protect distribution circuits and as a disconnecting device with a disconnecting function. The special selectivity properties to ensure high system availability are particularly noteworthy. The HS91 are designed for direct installation on a 4- or 5-pole busbar system (40mm). Rated currents from 20 to 63A and tripping characteristic E(selective).