Motor protection circuit breaker, 55 mm, CLASS 20 trip
Its CLASS 20 trip characteristic provides a 20-second overload response at 7.2× I_e, matching the thermal curve of standard NEMA-design B and IEC motors. The 55 mm width (3.5 module spaces on a 35 mm DIN rail per DIN EN 60715) and 149 mm depth fit standard motor-starter footprints. Screw-type terminals on the main circuit accept 2× (1 to 25 mm²) or 1× (1 to 35 mm²) solid or stranded copper — no ferrule required for the larger cross-section.
Clearance and mounting
Clearance requirements vary with system voltage: at 240 V no clearance is required; at 400 V allow 125 mm upwards and 50 mm downwards; at 500 V allow 100 mm upwards; at 690 V allow 80 mm upwards. Side clearance is 10 mm. These distances ensure arc-fault containment and thermal dissipation — critical when the breaker is packed into a dense panel.