Siemens 5SU1354-7LB20 SENTRON RCBO — 20 A, Type A, 10 kA
The Siemens 5SU1354-7LB20 is a 2-pole (1P+N) residual current circuit breaker with overcurrent protection (RCBO) from the SENTRON 5SU1 series. It combines a 20 A thermal-magnetic overcurrent release (tripping characteristic C) with a Type A residual current device in a single 36 mm wide unit. The 10 kA breaking capacity per EN 60898 means it can safely interrupt fault currents up to that level on a 230/240 V AC supply, making it suitable for final circuits in residential and commercial distribution boards where both short-circuit and earth-fault protection are required in one device.
The Type A RCD detects pulsating DC fault currents, which is essential for circuits supplying electronics, variable-speed drives, or appliances with rectifiers; Type A is the minimum requirement for most modern household and commercial installations. The 10 kA breaking capacity per EN 60898 certifies the device for use in installations where the prospective short-circuit current does not exceed 10 kA — common in distribution boards downstream of a main switch or upstream breaker.
Thermal derating and installation conditions
The 20 A rating applies at 30 °C ambient; derate progressively to 14.6 A at 70 °C (–). The device is 36 mm wide (2 width units) and 77 mm deep, with an installation depth of 70 mm. The 5SU1 design accepts supply from either top or bottom.