Line protection MCCB — 125 A, 4-pole, TM240 release
The 4-pole construction suits three-phase systems with a fully rated neutral — common in IT or TN-S networks where the neutral requires overcurrent protection. Breaking capacity is published across five voltage levels: 76 kA at 240 V AC, 53 kA at 415 V AC, 32 kA at 440 V AC, and 11.9 kA at both 500 V and 690 V AC.
Current-carrying capacity is temperature-dependent across the operating range. Above 50 °C the rating steps down: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. Plan the enclosure ventilation and busbar sizing around the actual ambient temperature inside the panel — a 70 °C internal ambient reduces available current by nearly 9 % from the 125 A base. Physical footprint is 101.6 mm wide, 130 mm tall, and 70 mm deep — a 4-pole MCCB that fits standard Siemens SENTRON mounting accessories and busbar systems. The N-conductor protection is set at 50 % of the phase rating, a common configuration for distribution boards where the neutral is sized smaller than the phases. Maximum power loss is 28.1 W. This figure drives the heat load inside the enclosure for thermal calculations, particularly in multi-breaker panels where cumulative losses affect the internal ambient temperature.
The part carries an optional motor drive extension (Product Extension / Optional / Motor Drive = Yes), enabling remote motorized operation for integration into automated power-management systems — relevant for vessel automation and bridge-integrated switchgear where remote tripping and reset are required.