The Siemens 3RU1116-1GB0-ZX95 is a SIRIUS thermal overload relay in Size S00, Trip Class 10, designed for 3-pole motor protection in industrial control panels. It mounts directly to a contactor — no separate DIN-rail footprint needed — and uses screw-type terminals for both main and auxiliary circuits. The IP20 front protection keeps live parts safe during panel access, and the ATEX certification (DMT 98 ATEX G 001) qualifies it for potentially explosive atmospheres where motor overload protection must meet directive requirements.
What Trip Class 10 means for motor protection
Trip Class 10 means the relay will trip within 10 seconds at a cold start under 7.2× the set current. That's the standard for standard-duty induction motors — pumps, fans, compressors — where the rotor can handle a brief locked-rotor event without damage. For higher-inertia loads (flywheels, crushers) you'd typically step up to Class 20 or 30; for submersible pumps or hermetic compressors, Class 10 is often the spec. The 3RU1116-1GB0-ZX95's 3-pole design covers all three phases, so a single-phase condition or phase imbalance trips the relay.
Mounting and panel fit
This relay fastens directly to the contactor (contactor mounting per), saving DIN-rail space. The Size S00 body measures 45 mm wide, 87 mm high, and 78 mm deep — compact enough for crowded subpanels. Mounting position is flexible: vertical surface with ±135° rotation or ±45° tilt forward/backward, so it adapts to enclosure layouts without derating. Clearance requirements: 0 mm upwards, forwards, and backwards; 6 mm at the sides; 0 mm downwards — meaning it can stack tight against adjacent components in a row.
Environmental and electrical ratings
Rated for continuous operation in ambient temperatures from -20 °C to +70 °C, with storage and transport range of -55 °C to +80 °C. The relay withstands 100% relative humidity during operation — no condensation concern in washdown or coastal environments. Shock resistance is 8g for 10 ms, covering most industrial vibration profiles. Surge voltage resistance is rated at 6 kV, matching IEC 60947-1 coordination requirements for 400 VAC systems. Auxiliary contact ratings: 1 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V — sufficient for PLC inputs or contactor hold coils.
Wiring and terminal capacity
Screw-type terminals on both main and auxiliary/control circuits. Main circuit accepts solid conductors: 2× (0.5…1.5 mm²) and 2× (0.75…2.5 mm²), plus AWG equivalents 2× (20…16) and 2× (18…14) and 2× 12. Finely stranded with core-end processing uses the same cross-sections. Auxiliary contacts take 2× (20…16) and 2× (18…14) AWG. The dual-wire capacity per clamp is useful for daisy-chaining control power or looping through the overload's NC contact to the contactor coil.