What this solid-state overload relay does — and the spec that matters for fit
The Siemens 3RB3016-2SB0-ZW96 is a SIRIUS solid-state overload relay in the S00 frame size, rated for a thermal current of 12 A and a rated insulation voltage of 690 V. It's designed to mount directly onto a contactor — the fastening method is contactor mounting, so it shares the same DIN-rail or screw-panel footprint as the contactor it pairs with. The Trip Class is 20E, which means it's set for slower, Class 20 motor protection curves — common for pumps, fans, and compressors where starting inrush is sustained longer than a standard Class 10 relay allows. The electronic overload release compensates for ambient temperature across -25 to +60 °C, so the trip point stays stable whether the panel is in a conditioned room or a hot machine skid. It's rated for any mounting position, and the auxiliary switch is integrated — no separate add-on block needed for the alarm or trip signal.
Auxiliary contact ratings — what the numbers mean for your control circuit
The integrated signaling contact carries 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V. That's the current it can switch in the control loop — enough to drive a PLC input or a small relay coil. At higher DC voltages the rating drops (0.55 A at 60 V, 0.3 A at 125 V, 0.11 A at 220 V), which is typical for DC switching where arc extinction is harder. If you're feeding a 24 VDC PLC input, the 2 A rating gives plenty of margin.
Physical fit and wiring
The overload relay measures 45 mm wide, 79 mm high, and 73 mm deep — a compact S00 footprint that fits standard 45 mm DIN-rail spacing when mounted on its matching contactor. Main circuit terminals accept solid or stranded wire: 1x (0.5 to 4 mm²) or 2x (0.5 to 2.5 mm²), terminated with screw-type terminals requiring a Pozidriv PZ 2 screwdriver tip. Wire preparation is straightforward with standard ferruled or solid conductors. The relay is rated for vibration resistance of 1–6 Hz at 15 mm amplitude and 6–500 Hz at 20 m/s² over 10 cycles, and shock resistance of 15g for 11 ms — tough enough for machine-mounted panels on conveyors or rotating equipment.
Note for message "tripped" — what it tells the control system
The spec carries a note: "for message 'tripped'." This means the integrated signaling contact (terminals 97/98) changes state when the overload relay has tripped on overcurrent or phase loss, providing a discrete signal to a PLC, HMI, or annunciator. The contact is rated for the switching capacities listed above, so it can drive a 24 VDC input directly without an interposing relay in most cases.
Compliance and substance restrictions
The relay lists a substance prohibitance date of 10/01/2009, indicating compliance with RoHS and REACH restrictions on hazardous substances as of that date. The SIRIUS series carries CE marking and is designed to IEC/EN 60947-4-1 standards for motor protection. No separate UL file number is listed in this spec set, but Siemens SIRIUS components are typically UL-recognized; verify the specific UL listing against your panel shop's requirements.