Line protection MCCB for 125 A feeder circuits
The Siemens SENTRON 3VA1112-4FD46-0AA0 is a 4-pole molded case circuit breaker rated at 125 A continuous current, fitted with a TM210 thermal-magnetic release. This is a line-protection version — no communication function, no ground-fault monitoring — built for straightforward overcurrent and short-circuit protection in distribution panels. The 125 A rating holds at 45 °C and 50 °C, then derates to 114 A at 70 °C, so the thermal curve matters if the breaker sits in a warm enclosure or next to other heat sources. Breaking capacity runs 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 500 V and 690 V. At 415 V, that 75.6 kA gives solid headroom for most industrial secondary distribution — you can coordinate downstream without worrying about the main tripping on a bolted fault. The TM210 release has an adjustable li (instantaneous trip) up to 1250 A, and the N-conductor protection is set at 50 % of the phase rating.
Panel fit and thermal management
Footprint is 101.6 mm wide by 130 mm tall by 70 mm deep — a 4-pole MCCB that fits standard Siemens SENTRON mounting. Front face carries IP40 protection, adequate for enclosed distribution boards but not for washdown environments. Maximum power dissipation is 28.1 W at full load; that heat has to leave the enclosure, so factor it into the cabinet thermal budget, especially when grouping several breakers. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The 125 A rating is only valid up to 50 °C — above that, follow the derating curve down to 114 A at 70 °C. If the panel ambient runs hot, size the breaker for the actual load current at the expected temperature, not the nameplate 125 A.