Load-break disconnect with shunt trip — what it is and what it does
The Siemens SENTRON 3VA1116-1AA42-0KH0 is a 4-pole switch disconnector built in an MCCB-style frame, rated for 160 A continuous current across the ambient range from 40 °C to 50 °C, with a slight thermal derating to 150 A at 70 °C. It carries a full load-break rating at 690 V AC and 600 V DC, making it suitable for isolating both AC motor circuits and DC bus sections in industrial panels. The unit ships with an integrated shunt trip (STL) release for 220–250 V DC or 208–277 V AC, plus a complement of 2 auxiliary switches HQ and 1 trip alarm switch HQ — enough to signal position and fault status back to a PLC or annunciator without adding external contact blocks.
Continuous current and thermal management
The 160 A rating holds flat through 50 °C, then drops to 158 A at 55 °C, 155 A at 60 °C, 153 A at 65 °C, and 150 A at 70 °C. The maximum power loss is 38 W. For a panel builder, this means the disconnect can be mounted in a standard IP40 enclosure without forced ventilation for most loads up to 160 A, provided the ambient inside the cabinet stays under 50 °C. Above that, the derating curve governs the usable current — a 150 A motor at 70 °C ambient is still within the thermal budget.
Integration and wiring notes
The disconnect measures 70 mm deep, 101.6 mm wide, and 130 mm high. The main circuit connects via busbar connections at the front terminals — no rear-panel bus work required. The shunt trip (STL) and auxiliary switches are factory-installed; the STL coil is rated for 220–250 V DC or 208–277 V AC, so it can be driven directly from a control transformer or a DC supply without an interposing relay. An optional motor drive can be added for remote switching. Mechanical service life is rated at 15,000 operating cycles typical.