The Siemens SENTRON 3VA1225-1AA42-0DH0 is a 4-pole switch disconnector in MCCB design rated for 250 A continuous current (Iu). It provides no overload or short-circuit protection — it's a disconnect-only device, meant for isolating a circuit under load or for use as a main switch where downstream protection handles the fault clearing. Rated operational voltage is 690 V AC (50/60 Hz) and 600 V DC, with an insulation voltage (Ui) of 800 V. That puts it solidly in the 400 V / 480 V industrial panel range, with headroom for 690 V systems. The built-in undervoltage release (UVR) operates on 208-230 V AC 50/60 Hz. If control voltage drops, the UVR trips the disconnector open — a common safety requirement for motor circuits or emergency-stop chains where loss of control power should drop the load.
Dimensions are 140 mm wide, 158 mm high, 70 mm deep. The main circuit connects via busbar connection at the front terminals — typical for panel-mount MCCB-style disconnectors on a busbar system. IP40 on the front keeps dust out of the enclosure face; the back and sides rely on the panel enclosure for ingress protection. Auxiliary contact block provides 2 auxiliary switches (CO contacts) plus 1 trip alarm switch (HQ). The trip alarm signals when the disconnector has opened due to a fault or UVR trip — useful for remote status monitoring on a PLC input.