The Siemens 3VA9908-0BB26 is an undervoltage release accessory for the SENTRON 3VA molded-case circuit breaker family, specifically designed for 3VA1 and 3VA20 through 3VA25 frames.
The 2.5 VA apparent power draw is the coil burden the control transformer or UPS must supply; at 380-400 V that's roughly 6-7 mA, negligible for most control circuits. The 25.7 mm width, 65.1 mm height, and 28.8 mm depth define the panel space it occupies inside the breaker's accessory compartment — not a standalone DIN-rail mount. It clips into the three accessory slots on the side of the 3VA breaker, so no additional enclosure width is consumed.
Deployment context
Installed inside the 3VA breaker's accessory bay, this release is wired in series with the breaker's undervoltage coil circuit — typically fed from the load-side bus so that loss of voltage trips the breaker open. The 10 mm stripped length (0.4 in) on the coil leads matches standard ferrule-terminated control wiring; no special crimp tool needed.