Switch disconnector, 125 A, no overload protection
The Siemens SENTRON 3VA1112-1AA42-0DH0 is a 4-pole switch disconnector in MCCB design, rated 125 A continuous with no overload or short-circuit protection — it is a disconnect, not a breaker. Rated operating voltage is 690 V AC / 600 V DC, with an insulation voltage of 800 V. The 125 A rating holds flat across the entire operating temperature range from 40 °C to 70 °C, so no derating calculation is needed for warm panel environments. Built into a 101.6 mm wide, 130 mm tall, 70 mm deep frame, it mounts via busbar connection on the main circuit — front terminal arrangement. The IP40 front protection is standard for enclosed panel mounting; the switch is not intended for washdown or outdoor exposure.
Integrated undervoltage release and auxiliary switching
This variant ships with an undervoltage release (UVR) rated 208-230 V AC 50/60 Hz, plus 2 HQ auxiliary switches and 1 HQ trip alarm switch — three CO contacts total. The UVR trips the disconnector when control voltage drops, which is standard for safety isolation in machine tools or conveyor lines where loss of control power should open the load circuit. Maximum power loss is 38 W at rated current. Mechanical service life is 15 000 operating cycles typical. An optional motor drive can be added via the product extension slot.