What it is and what it does
The Siemens 3RU1116-0JC1 is a SIRIUS thermal overload relay — the part that sits downstream of a contactor to protect a motor against sustained overcurrent by mimicking its heating curve. It's sized for the S00 frame, which is the compact footprint Siemens uses for smaller motor starters up to around 7.5 kW at 400 V. The CLASS 10 trip characteristic means it will open the circuit within 10 seconds at 7.2× the full-load current setting, fast enough to protect standard induction motors during a stall or locked-rotor event without nuisance-tripping on normal starting inrush.
Key ratings and what they mean for fit
Rated for AC-3 duty up to 690 V, this relay covers the full low-voltage motor range across 400 V, 480 V, and 575 V systems common in industrial plants. The IP20 rating on the front means it's protected against finger contact and solid objects over 12 mm, but it's designed for installation inside a panel enclosure — not for open washdown areas. Shock resistance of 8g for 10 ms is typical for relay mounting on a contactor that sees vibration from contactor closure or nearby motor starting; the mounting position allows rotation of ±135° and tilt of ±45° to the front and back, which gives flexibility in tight cabinets as long as the vertical mounting surface is maintained.
Mounting and wiring
Mounts stand-alone (not pre-assembled to a contactor) using the S00 frame's rail-clip system — snaps onto 35 mm DIN rail. The main circuit uses Cage Clamp terminals accepting 2×(0.5…2.5 mm²) solid or 2×(0.5…1.5 mm²) finely stranded with ferrule; auxiliary and control circuits use the same Cage Clamp style. Clearance: 0 mm upwards, forwards, backwards, and downwards — meaning it can be stacked flush against adjacent devices or panel walls, which is rare for a thermal relay and a real space-saver in dense panels. Side clearance of 6 mm is needed for airflow and wiring access.