The Siemens 3RU1136-4ED1 is a SIRIUS S2 thermal overload relay, Trip Class 10, designed for motor protection in control panels. It carries ATEX certification (DMT 98 ATEX G 001), confirming suitability for potentially explosive atmospheres per the certificate scope. The main circuit uses screw-type terminals; the auxiliary and control circuit uses Cage Clamp terminals for tool-less wiring.
Key ratings and what they mean for fit
Trip Class 10 means the relay must trip within 10 seconds at a locked-rotor current of 7.2× the full-load current setting — standard for standard-start induction motors driving pumps, fans, and conveyors where rapid overload protection is needed. The auxiliary contact ratings cover control circuits at common voltages: 1 A at 24 V, 3 A at 120 V, 2 A at 230 V, and 1 A at 400 V. These are the switching capacities for the N/O and N/C contacts feeding the PLC input or contactor hold-in circuit. Surge voltage resistance rated at 6 kV provides coordination with upstream surge protection devices, reducing the risk of nuisance tripping or contact welding during transient events on the line. Operates across -20 to +70 °C and stores at -55 to +80 °C, covering most indoor panel environments and cold-weather shipping. The 100 % relative humidity rating confirms suitability for condensing environments — typical in washdown areas or coastal installations.
Mounting and integration
Mounts with a vertical mounting surface, rotatable ±135° and tiltable ±45° front-to-back. This flexibility allows the relay to fit into tight panel layouts where the contactor is oriented non-standard. Stand-alone installation — no backplate adapter required. Clearance requirements: 0 mm upwards, forwards, backwards, and downwards; 6 mm at the side. This zero-clearance top and bottom simplifies panel layout — the relay can be stacked directly above or below the contactor without extra spacing for heat dissipation. Main circuit wiring accepts solid 2x (0.5…2.5 mm²) and stranded up to 2x (0.75…25 mm²) or 0.75…35 mm². AWG equivalents: 2x (18…3) and 1x (18…1). Auxiliary contacts take 2x (20…14) AWG. Finely stranded with core-end processing: 2x (0.5…1.5 mm²).