The Siemens 3VA9978-0BL32 is a left-side shunt trip (auxiliary release) for the 3VA4, 3VA5, and 3VA6 SENTRON molded-case circuit breaker families. It operates on 110-127 V AC 50/60 Hz or DC, drawing up to 40 VA (AC) or 40 W (DC) at maximum load. That power consumption is the peak the coil pulls during the trip event — steady-state draw is negligible, so it won't load the control transformer on a multi-breaker panel. The 31.2 mm depth, 25.7 mm width, and 65.1 mm height let it tuck into the left accessory slot of the breaker without crowding adjacent wiring.
Snaps into the left-side accessory bay of the 3VA4/5/6 breaker frame. No DIN-rail footprint of its own — it's captive to the breaker once assembled. The three accessory slots on the breaker accept this shunt trip plus other auxiliaries; this unit occupies one slot. Stripped length of 10 mm (0.4 in) on the coil wires matches standard ferrule preparation for the breaker's terminal block.