What this MCCB is and what it carries
The Siemens 3VA1110-4EF32-0DA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — the primary feeder breaker in a distribution panel or the incoming protective device for a motor control center branch. It is a 3-pole unit rated 100 A continuous at 40 °C, with a TM240 thermal-magnetic trip unit that handles overload and short-circuit protection in one package. Breaking capacity is the headline number that decides whether this breaker clears a fault without rupturing. At 240 V it interrupts 121 kA; at 415 V it still holds 75.6 kA, dropping to 52.5 kA at 440 V and 11.9 kA at both 500 V and 690 V. For a 100 A frame, those are high-interrupting ratings — it is sized for installations with high available fault current, not a low-fault residential panel. The part includes an undervoltage release (UVR) as a built-in auxiliary release. That means if the control voltage drops below the dropout threshold, the breaker trips — a common requirement for safety circuits that need to drop power on loss of control supply. No separate undervoltage module to buy and mount.
Thermal derating and panel fit
The 100 A rating holds flat from 40 °C through 50 °C — no derating needed in a warm enclosure. At 55 °C it steps down to 98 A, at 60 °C to 96 A, at 65 °C to 94 A, and at 70 °C to 91 A. For a panel that runs hot, the 70 °C figure (91 A) is the one to use for sizing. Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep. The 70 mm depth fits a standard panel with room for wiring gutters. Maximum power loss is 27.5 W. That is the heat the breaker dumps into the enclosure at full rated current — relevant for thermal calculations in a sealed or high-density panel.