The Siemens 5SU9156-7KK50 is a 2-pole (1P+N) RCD-operated circuit breaker — an RCBO — from the SENTRON 5SU9 series. It combines overcurrent protection (characteristic C, 50 A rated) with residual-current protection (30 mA, Type A) in a single 36 mm wide module, saving a DIN-rail position compared to separate MCB + RCCD. The 50 A rating at 30 °C is the headline number, but the derated values matter for a warm enclosure: at 40 °C it carries 47 A, at 45 °C it carries 45.5 A, and at 50 °C it carries 43.5 A (–). The 10 kA rating gives headroom for industrial panels with higher prospective fault current — the 6 kA figure is the limit for residential or light commercial boards. Overvoltage category III confirms it is rated for fixed-installation downstream of the utility meter. The 30 mA trip threshold protects against direct-contact shock hazard. Touch protection is built in.
Width is 36 mm, depth is 77 mm, height is 90 mm. Installation depth is 70 mm. Solid and stranded conductor range is 0.75 to 35 mm².