The Siemens 5SU9306-1KK25 is a 1P+N RCD-operated circuit breaker (RCBO) from the SENTRON 5SU9 series, combining overcurrent protection and residual current detection in a single 18 mm wide module.
The 25 A rating at 30 °C is the headline number, but the real-world current capacity drops as ambient temperature rises: 23.5 A at 40 °C, 22.75 A at 45 °C, 21.75 A at 50 °C, and 20.25 A at 55 °C.
Mounting and wiring — fits standard DIN rail, 1 width unit
The installation depth is 70 mm, with an overall depth of 77 mm including the front.