What it is and what it does
The Siemens 3RU2116-1BC0 is a SIRIUS thermal overload relay, size S00, designed to protect motors against overcurrent and phase failure. It mounts directly to a contactor, making it a compact, integrated motor-protection package for control panels. Rated for CLASS 10 trip characteristics, this relay trips within 10 seconds at 7.2× the set current — fast enough to protect standard induction motors during locked-rotor events without nuisance tripping on normal starts. The relay handles switching across a wide voltage range: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V, and 0.75 A at 690 V. This covers most control-circuit voltages found in industrial installations.
Integration and mounting
Fastens directly to a contactor (contactor mounting), eliminating separate DIN-rail space and wiring. Mounting position is any, so it fits tight enclosures without orientation restrictions. Main circuit connections use spring-loaded terminals, accepting 2x (0.5 to 2.5 mm²) solid or stranded wire. This speeds panel wiring and resists loosening under vibration. Dimensions are 45 mm wide, 87 mm high, 70 mm deep — a compact footprint that fits the S00 contactor frame.
Environmental and compliance
Operating temperature range is -40 to +70 °C, with storage and transport tolerance from -55 to +80 °C. Temperature compensation is active from -40 to +60 °C, ensuring accurate trip characteristics across the working range. Substance prohibitance dated 10/01/2009 indicates RoHS compliance for the European market.
Sourcing posture
As a current-production SIRIUS component, the 3RU2116-1BC0 is sourced to order against an RFQ. No last-time-buy or phase-out constraints apply. The integrated auxiliary switch and thermal release design mean this is a direct-fit replacement for existing S00 overload relay slots in Siemens contactor assemblies.