Line protection breaker, 125 A, four poles
The Siemens SENTRON 3VA1112-6GF46-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 125 A continuous current, configured for line protection with a TM240 thermal-magnetic trip unit. It carries a 220 kA interrupting capacity at 240 V, dropping to 154 kA at 415 V and 75.6 kA at 440 V — still substantial for most industrial distribution panels. The 4-pole design means it switches all three phases plus neutral, with 100% N-conductor protection.
What the ratings mean for your panel
The 125 A rating holds up to 50 °C ambient; above that, derate to 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. If your enclosure runs hot — say a packed MCC lineup — that 114 A at 70 °C is the number to size against, not the 125 A label. The TM240 release has an adjustable li max of 1,250 A, giving you a 10× magnetic pickup window for motor-start inrush without nuisance trips. Front IP40 protection keeps dust out of the breaker face; the rest of the case is open to the panel interior. Mounting dimensions are 130 mm height, 101.6 mm width, 70 mm depth — fits standard SENTRON 3VA cutouts. The 800 V rated insulation voltage (Ui) covers 480/600 VAC systems with headroom.