What it is and what it protects
The Siemens 3RB3016-2RE0 is a SIRIUS solid-state overload relay, size S00, designed to protect three-phase motors against overload and phase failure. It is an electronic overload release, meaning it uses a microprocessor to model motor heating rather than a bimetallic strip, giving it better accuracy and repeatability over the temperature range. Rated thermal current is 0.4 A at 690 V, with a CLASS 20E trip curve — that means it will trip in 20 seconds at 7.2× rated current, matching the standard for motor starting with moderate inertia loads like fans or centrifugal pumps. The 0.4 A rating applies at both 480 V and 600 V, so derating for voltage is not a concern here. The relay mounts directly onto a contactor (contactor mounting), not on a DIN rail. It snaps onto the S00 frame contactor, which saves panel width — the relay itself is 45 mm wide and 90 mm deep, so the combined contactor-plus-relay stack stays within the contactor's footprint.
Auxiliary contact ratings and wiring
An integrated auxiliary switch provides the signaling contact for the tripped state. The contact ratings are given across several voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and 0.4 A at 480/600 V. At 24 VDC, the contact is rated 2 A; at 60 VDC it drops to 0.55 A, and at 125 VDC to 0.3 A. These are the make/break capacities for the signaling circuit — useful for driving a PLC input or a remote alarm lamp. The main circuit terminals are spring-loaded, accepting 2× (0.25 to 1.5 mm²) solid or stranded wire. The screwdriver shaft diameter for the auxiliary terminals is 5 to 6 mm, with a Pozidriv PZ 2 tip.
Environmental and mechanical limits
Operating temperature range is -25 to +60 °C, with temperature compensation active over that full span. Storage and transport range is -40 to +80 °C. The relay is rated for 15g shock at 11 ms, and vibration resistance per IEC 60068-2-27: 1–6 Hz at 15 mm amplitude, 6–500 Hz at 20 m/s² for 10 cycles. Mounting position is any, which simplifies panel layout. The note on the product line reads 'for message "tripped"' — this is the auxiliary contact that changes state when the relay trips, providing a discrete signal to a controller or annunciator.