The unit is 1P+N, switching the line conductor while the neutral is switched through but not protected against overcurrent. Breaking capacity is rated at 10 kA per EN 60898 and 20 kA per IEC 60947-2, which gives the 5SU1354-1LB10 headroom for installation at the origin of a sub-distribution board where fault currents can exceed the lower standard. The design is listed as short-time delayed G and super resistant K, which means the residual-current element tolerates brief surge currents (from lightning or capacitor switching) without nuisance tripping, and the overcurrent element handles higher inrush without degrading — provided the prospective short-circuit current stays within the 20 kA IEC rating.
At 40 °C it derates to 9.5 A, at 50 °C to 9 A, and at 60 °C to 8.5 A. By 70 °C the continuous current is 7.7 A. This matters in a sealed enclosure or a crowded DIN rail where internal temperature rise is unavoidable — the designer must either load the circuit below the derated figure or ventilate the panel to keep ambient under 40 °C. Mounting position is unrestricted, which simplifies layout in a vertical or horizontal busbar system. The 5SU1354-1LB10 occupies 2 modular width units (36 mm) on the DIN rail, with an installation depth of 70 mm and overall depth of 77 mm.