The Siemens SENTRON 3VA9978-0BA20 is a shunt trip auxiliary release designed as a snap-in accessory for 3VA4 molded-case breakers and 3VA51 through 3VA54, plus 3VA61 through 3VA64 frames. The part occupies three accessory slots on the breaker, so verify slot availability on the base unit before specifying. Dimensions are 31.2 mm deep by 21.7 mm wide by 65.1 mm tall; the stripped length for wiring is 10 mm (0.4 in).
Integration note — wiring and panel fit
Wire termination requires a 10 mm strip length. The accessory slots accept the shunt trip module without additional DIN-rail space — it mounts directly onto the breaker's side accessory bay. The 340 VA inrush is a pulse, not a hold-in load — the coil drops out after the trip mechanism operates. Size the control transformer and wiring for that peak draw if multiple shunt trips fire simultaneously in a coordinated trip scheme.