Siemens 3RU2116-4AC1 — SIRIUS Thermal Overload Relay, Size S00, Trip Class 10
The Siemens 3RU2116-4AC1 is a SIRIUS thermal overload relay in Size S00, designed to protect AC motor circuits against overload and phase failure. It's a Trip Class 10 device, meaning it will trip within 10 seconds at 7.2× the set current — fast enough to protect standard induction motors during a stall or locked-rotor condition. The relay mounts standalone in any position and connects via spring-loaded terminals, so no screwdriver is needed for the main circuit wiring. Rated insulation voltage is 690 V, and it covers motor power ratings up to 7.5 kW at 400 V and 11 kW at 690 V.
Auxiliary Contact Ratings — What the Numbers Mean for Your Control Circuit
The integrated auxiliary switch on this relay is rated for several common control voltages. At 24 V it switches 2 A; at 120 V it handles 3 A; at 230 V it's rated 2 A; and at 400 V it drops to 1 A. For DC control circuits, it's rated 0.3 A at 60 V and 0.22 A at 110/125 V. These are the maximum continuous make-and-break ratings — if you're driving a PLC input or a contactor coil, stay under these values to avoid welding the contacts. The auxiliary is integrated, so there's no separate switch block to order.
Mounting and Wiring — Standalone, Spring-Loaded Terminals
This relay mounts standalone — no DIN rail adapter required, though it can be snapped onto a contactor if needed. The spring-loaded terminals on the main circuit accept 2× (0.5 to 2.5 mm²) solid or stranded wire. The auxiliary switch uses the same terminal type. A 3 mm screwdriver shaft is specified for the terminal screws on the auxiliary side. Mounting position is any, so it fits tight panels without worrying about orientation.
Environmental and Compliance
Operating temperature range is -40 to +70 °C, with temperature compensation from -40 to +60 °C. Storage and transport range is -55 to +80 °C. MTTF with high demand rate is 2,280 years.