What the ratings mean for fit
The Siemens SENTRON 3VA1112-4ED26-0AA0 is a 2-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current Iu of 125 A at 40 °C through 50 °C, derating to 114 A at 70 °C. The interrupting capacity is 121 kA at 240 VAC and 75.6 kA at 415 VAC — figures that govern its use in high-fault panels where upstream SCCR must be coordinated. The TM210 thermal-magnetic release provides fixed short-circuit pickup at 1250 A (10× Iu), so selectivity with downstream breakers needs to be verified against that threshold.
Dimensions and panel fit
The breaker occupies a 50.8 mm width (2 in) on the DIN rail, with a depth of 70 mm and height of 130 mm. Front IP40 protection means it is suited for enclosed panels where splash or dust ingress is not a concern. The 2-pole footprint matches standard SENTRON 3VA spacing, so a panel originally laid out for a 3VA1112-5EE32-0AA0 will accept this unit without rewiring — same mounting centers, same bus-bar pitch.
Thermal derating and power loss
The breaker holds its full 125 A rating up to 50 °C ambient. Above that, derate linearly: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. Maximum power dissipation is 18.74 W at rated load — a figure to include in enclosure thermal calculations. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.