EN 61009-1 specifies the general requirements for residual current-operated circuit-breakers (RCCBs) and their combination with overcurrent protection devices (RCBOs). It covers the design, construction, performance, and testing of these devices to ensure safety and reliability in residential, commercial, and industrial installations. The standard addresses aspects such as operational characteristics, protection against electric shock, and mechanical durability. EN 61009-1 is essential for ensuring that RCCBs and RCBOs provide effective protection against electrical faults and hazards.