Motor protection circuit breaker with integrated auxiliary contacts
The Siemens 3RV2011-1HA15-Z is a molded case circuit breaker (MCCB) purpose-built for motor branch circuit protection. It combines a Class 10 overload trip unit adjustable from 5.5 to 8 A with a fixed instantaneous magnetic trip set at 104 A. The Class 10 trip curve means it will trip within 10 seconds at 600% of the set current — fast enough to protect standard induction motors during a locked-rotor event without nuisance tripping on normal starting inrush. This variant includes factory-integrated transverse auxiliary switches (1 NO + 1 NC), which eliminates the need for a separate auxiliary contact block on the side. The screw terminal connections are rated for standard switching capacity — suitable for most fixed-speed motor applications in industrial control panels. The multi-unit packaging (24 units per pack) suggests this is a volume-stocked line item for panel builders or OEMs with consistent BOM consumption.
What the ratings mean for your panel
The 5.5 to 8 A overload adjustment range covers motor FLA from about 5.5 A (roughly 2.2 kW at 400 V) up to 8 A (about 4 kW at 400 V). The 104 A instantaneous trip is a fixed magnetic threshold — it clears short-circuit faults above that level without waiting for the thermal bimetal. The 1 NO + 1 NC auxiliary switches are wired into the control circuit for status feedback (run/fault indication) or to interlock with a contactor coil. The screw terminals accept standard ring or fork lugs; torque per the terminal marking on the device face.