The Siemens 5SU9156-7VK50 is a SENTRON RCBO — an RCD-operated circuit breaker that combines overcurrent protection and residual-current detection in a single 2-module (36 mm wide) package. The Type A residual-current element detects pulsating DC fault currents, not just sinusoidal AC — so it covers variable-speed drives, LED drivers, and other electronics that generate half-wave or phase-controlled leakage.
Breaking capacity and derating
Current derating is published: 50 A at 30 °C, 47 A at 40 °C, 45.5 A at 45 °C, 43.5 A at 50 °C, 40.5 A at 55 °C.
Installation and wiring
Touch protection is built in. IP20 rating applies when the distribution board is installed with conductors connected. Halogen-free and silicon-free construction. Overvoltage category III, energy limiting class 3.