Blocking unit for fault current protection switch, includes safety device controlling blocking function, by removing it when fault current arises

摘要

A blocking unit (4-10) blocks the switching mechanism (1-3) of the protective switch. The new feature is a safety device (11, 12, 15, 19-21) controlling this blocking function, such that when a fault current arises, the blocking is removed. When the blocking unit is activated, the safety device activates automatically. On deactivation of the blocking unit, it is automatically de-activated. The safety device can be deactivated automatically when applying a test current (Ip). An independent claim is included for corresponding interruption-free testing of a fault current protection switch.