The Siemens 3VA1112-1AA32-0KH0 is a SENTRON switch disconnector in an MCCB (molded case circuit breaker) design, meaning it occupies the same panel footprint and uses the same mounting hardware as a 3VA breaker but is intentionally built without overload or short-circuit protection elements. It is a 3-pole device rated for a continuous current Iu of 125 A, with a maximum operational voltage of 690 V AC (50/60 Hz) and 500 V DC. This makes it suitable for isolating a circuit under load — a load-break disconnect — rather than protecting it against faults. The part includes a shunt trip release (STL) rated for 220–250 V DC or 208–277 V AC, which allows remote tripping via a control signal. The auxiliary contact configuration is factory-installed and wired to a front terminal block.
This is not a breaker rating — there is no thermal-magnetic trip unit to protect downstream conductors. The switch disconnector is sized for the load current, and overcurrent protection must be provided separately upstream. Short-time withstand capability is listed at 2 kA for both 0.5 s and 1 s durations. This means the switch can hold closed under a fault current of up to 2 kA for up to 1 second without welding or damage — enough to coordinate with an upstream breaker that clears slower faults, but not a high-fault-rated disconnect. For systems with available fault current above 2 kA, the switch must be backed by a current-limiting device. Maximum power loss is 38 W at rated current, which matters for thermal management inside a sealed enclosure — that heat must be dissipated to avoid derating adjacent components.
The 3VA1112-1AA32-0KH0 uses the standard 3VA frame-160 footprint: 76.2 mm wide (roughly 4.5 module spaces on a DIN rail), 130 mm tall, and 70 mm deep. It mounts via the same busbar connection system as other 3VA MCCBs, with front terminals for the main circuit. The busbar connection type means it plugs onto a vertical or horizontal busbar system rather than accepting lugged cables directly — order the appropriate busbar adapter or pre-assembled busbar kit separately. This is standard for panel-mounted switchgear inside a rated enclosure. The optional motor drive allows remote motorized operation for automated isolation sequences.