The Siemens 3VA9988-0AB34 is a SENTRON short-circuit signaling switch — a changeover contact block that snaps into the 7 mm wide accessory slot on 3VA1 molded-case circuit breakers (250, 400, and 630 A frames). It's the part that tells your PLC or annunciator that the breaker tripped on a fault, not that someone hit the handle. Rated at 6 A thermal current (Ith), the switch carries AC-15 pilot-duty loads at 3 A up to 240 V and DC-13 solenoid loads at 0.8 A at 24 V — enough to drive a contactor coil or a panel indicator without an interposing relay. The DC-13 rating drops to 0.4 A at 48 V and 0.1 A at 250 V, so keep that in mind if you're switching a DC holding coil at higher voltages. At 7 mm wide and 56 mm tall, it fits the narrowest slot on the breaker's right side — you won't lose a full module width for a single alarm contact. The 30 mm depth sits flush with the breaker body, so it doesn't steal wireway space in a tight panel.
Integration & Environment
Pollution degree 3 and overvoltage category III mean it's rated for the dirtier, higher-surge environment inside an industrial panel — not just a clean office switchboard. Surge voltage resistance is 4 kV, so it handles switching transients from motor starters and contactors without welding its own contacts shut. Stripped length is 15 mm (0.6 in) — standard for screw-clamp terminals on these Siemens accessories. The spring-cage or box lug on the breaker itself takes the same strip length, so you're not changing your wire-prep routine.