Key ratings and what they mean for a motor branch circuit
The Siemens SENTRON 3VA2110-7MS32-0BC0 is a 3-pole molded case circuit breaker (MCCB) in the starter protection variant, meaning it is designed to coordinate with a contactor and overload relay for motor branch-circuit protection per IEC 60947-4-1. Its rated continuous current Iu of 100 A sets the thermal capacity for the breaker body; at 40 °C ambient it carries 100 A without derating, and the current stays at 100 A through 50 °C, then tapers to 90 A at 70 °C (–). The 100 A frame is sized for a motor full-load current in that range, with the 240 V breaking capacity of 330 kA and 415 V rating of 242 kA handling high available fault currents typical on industrial secondary substations.
Overcurrent release and auxiliary trip integration
The overcurrent release is the ETU310M, an electronic trip unit with adjustable thermal-magnetic or electronic curves depending on the variant—here configured for starter protection, typically with a higher magnetic pickup to ride through motor inrush. The breaker includes an undervoltage release (UVR) as the auxiliary release; when the control voltage drops, the UVR trips the breaker on loss of voltage, a standard requirement for motor starters to prevent automatic restart. The integrated auxiliary trip module carries order code 3VA9608-0BB11, and the basic switch assembly is 3VA2110-7MS32-0AA0. Two auxiliary switches (HQ type) signal the breaker status to a PLC or contactor coil circuit.
Physical fit and panel integration
Mounting dimensions: 105 mm width, 181 mm height, 86 mm depth. The 105 mm width is the standard 4-module (4× 27 mm) SENTRON 3VA2 frame, which fits Siemens SENTRON panelboards and distribution boards with plug-in or fixed-mount bases. Depth of 86 mm leaves clearance for rear-connected busbars and wiring tunnels. Operating temperature range from -25 °C to 70 °C and storage from -40 °C to 80 °C cover most indoor industrial enclosures. Maximum power loss is 75 W—factor that into enclosure thermal rise calculations.