Siemens 5SU1354-1KK08 is a SENTRON RCBO, 2-module-wide (36 mm), 1P+N, 2-pole, Type C. Rated 8 A at 30 °C ambient, with a derating curve down to 5.84 A at 70 °C — the installer sizes the load current against the 30 °C figure and applies the derating if the panel runs hot. Breaking capacity is 10 kA per EN 60898 (the standard for household and similar installations) and 20 kA per IEC 60947-2 (the industrial standard), so it handles fault currents up to 20 kA in an industrial distribution board where the prospective short-circuit current is higher.
Depth 77 mm, installation depth 70 mm. Supply from top or bottom.
Surge voltage resistance rated at 4 000 V. The 1P+N design protects one phase conductor; the neutral is switched but not protected.