The Siemens SENTRON 3VM9908-0BB23 is an undervoltage release accessory for 3VM molded case circuit breakers rated up to 630 A. It operates on a 110 V AC control supply at 50/60 Hz, drawing a maximum apparent power of 2 V·A.
Rated insulation voltage (Ui) is 690 V, and surge voltage resistance is 4 kV — both match the insulation coordination of a 3VM breaker installed in an overvoltage category III environment with pollution degree 3. That means this release is designed for the fixed-installation panel environment (PD3 is typical of control cabinets with conductive dust or humidity, not clean-room or sealed enclosures). Physical footprint: 65.1 mm high, 25.7 mm wide, 28.8 mm deep. The 25.7 mm width fits alongside the breaker in a typical distribution panel. Stripped length is 10 mm (0.4 in) — standard for screw-clamp terminals on SENTRON accessories. Strip to that mark; over-stripping leaves bare conductor exposed past the clamp.
Lifecycle status is active (current production). No phase-out or last-time-buy notice exists for this order code.