Pluggable surge arrester for 1-phase power supply networks with separate N and PE (3-wire system: L1, N, PE). Features a high-power varistor between L and N, and a leakage current-free gas-filled surge arrester between N and PE. It includes function monitoring and disconnection of the individual protection paths in the event of a fault. There is an operating current-free (mechanical) optical defect indication at each protection plug and remote fault indication via a common potential-free changeover contact. The base element can be mounted with variable connections (outer conductor from above or below). Protective plugs can be inserted into the base element rotated by 180° (plug labeling remains legible). Mechanical coding of the base element and plug prevents incorrect insertion of connectors. There is a labeling option for protective plugs and terminals, as well as biconnect terminals for connecting round conductors and wiring bridges.