RCD-operated circuit breaker for final circuits
The Siemens 5SU9156-7VK16 is a SENTRON RCD-operated circuit breaker (RCBO) combining overcurrent and residual current protection in a single 2-module-width (36 mm) package. The 1P+N design switches the line conductor only; the neutral is switched internally for isolation but not protected against overcurrent. Feed can enter from top or bottom, which simplifies busbar routing in a crowded enclosure.
Mounting position is unrestricted — horizontal, vertical, or flat — which helps when fitting into a shallow gland plate or a tight corner of a control panel. Rated IP20 with the distribution board installed and conductors connected — suitable for dry indoor enclosures only. Ambient temperature range is -40 °C to 75 °C, but the continuous current derates above 30 °C: 15.04 A at 40 °C, 14.56 A at 45 °C, 13.92 A at 50 °C, and 12.96 A at 55 °C.
Surge voltage withstand is 4 kV; surge current withstand (8/20 µs) is 1 kA. The test button operates down to 125 V, so it can be verified even on a lightly loaded phase.