What it is and what it does
The Siemens 3RU1116-1CB0-ZW98 is a SIRIUS thermal overload relay in Size S00, designed for 3-pole motor protection up to the CLASS 10 trip characteristic — meaning it will trip within 10 seconds at a cold start under locked-rotor conditions, which is the standard for standard induction motors driving pumps, fans, and conveyors. It mounts directly onto a contactor (contactor mounting) and uses screw-type terminals for both the main and auxiliary circuits, accepting solid wire from 2x (0.5... 1.5 mm²) and 2x (0.75... 2.5 mm²) per pole. The front face is IP20 finger-safe, and the unit carries ATEX approval (DMT 98 ATEX G 001) for use in potentially explosive atmospheres — a key check for Ex-rated panels.
Key ratings and what they mean for fit
Trip Class 10 is the headline: it defines the maximum trip time at 7.2× rated current. For a motor starting a high-inertia load (like a centrifuge or crusher), a CLASS 10 relay may nuisance-trip during start-up — in that case you'd step up to CLASS 20. For most general-purpose motor circuits, CLASS 10 is the correct choice. The auxiliary contact ratings cover common control 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 make/break capacities for the N/C and N/O contacts wired into the control loop. Power dissipation per pole is 1.9 W, so the total heat load inside a panel with three poles is about 5.7 W — factor that into your enclosure thermal calculation, especially if the relay is stacked next to other heat sources. Surge voltage resistance is rated at 6 kV, which means the relay can withstand transient overvoltages typical in industrial environments without flashover — important for panels fed from long cable runs or near VFDs.
Where it goes and how it mounts
This relay clips directly onto a SIRIUS contactor of matching Size S00 — no extra bracket or wiring between the contactor and relay. The mounting position allows rotation of ±135° on a vertical surface and tilting ±45° forward/backward, giving flexibility in tight enclosures. Clearance requirements: 0 mm upwards, forwards, and backwards, 0 mm downwards, and 6 mm at the side — so it can be stacked directly against adjacent devices on the DIN rail without extra spacing. Dimensions are 45 mm wide, 87 mm high, and 78 mm deep — a compact footprint for a 3-pole overload relay.
Lifecycle and sourcing reality
For a BOM freeze or a line-down replacement, this part is a standard catalog item with no imminent obsolescence concern. We can quote it to order against an RFQ — no surplus or broker channel needed.