The Siemens SENTRON 3VA1225-1AA42-0BH0 is a 4-pole switch disconnector rated for 250 A continuous current — it is not a circuit breaker and provides no overload or short-circuit protection, so it is sized for isolation and switching duty where upstream protection is already in place. Rated operational voltage is 690 V AC and 600 V DC. The integrated undervoltage release (UVR) operates on 24 V DC — if the control voltage drops, the disconnector trips open, which is a common safety interlock for motor feeder circuits or emergency-stop chains. Auxiliary contact configuration includes 2 normally-open/normally-closed auxiliary switches plus a dedicated trip alarm switch (HQ type), giving three CO contacts total for status feedback to a PLC or indication lamp.
Panel Fit & Integration
Dimensions are 140 mm wide by 158 mm tall by 70 mm deep — the 70 mm depth is notably shallow for a 250 A rated device, which helps in tight enclosure layouts where gland-plate clearance is limited. Front-face protection is IP40, so the front panel is touch-safe against tools and fingers, but the device is not sealed against washdown — install in a clean, dry cabinet or add an IP-rated enclosure. Main circuit connection is busbar-type via front terminals, which suits panel builders who prefer busbar stacking over cable lugs; an optional motor drive can be added for remote switching.
What This Part Is Not
Because it has no overcurrent release (no thermal or magnetic trip unit), this is strictly a switch disconnector — do not specify it where branch-circuit protection is required. It is intended for isolation, maintenance disconnect, or load-break switching under rated current. Rated short-time withstand is 3 kA for both 0.5 s and 1 s — enough for coordination with upstream fuses or a molded-case breaker, but not for high-fault applications above that threshold.