What this relay is and what it does
The Siemens 3RU2126-1DB0-ZX95 is a SIRIUS thermal overload relay, Size S0, CLASS 10. It mounts onto a contactor. The overload release is thermal (bimetal), with an integrated auxiliary switch that provides a signal contact for the control system — the note "for message Tripped" on the order code indicates the auxiliary contact is wired to report a trip condition, not just to drop out the contactor coil. Rated insulation voltage is 690 V. Power dissipation per pole is 1.9 W.
Mounting and wiring
Fastening method is contactor mounting — the relay snaps onto a matching Siemens SIRIUS contactor without tools. Mounting position is any orientation. Dimensions are 85 mm wide × 85 mm high × 45 mm deep — a compact footprint for Size S0. Main circuit terminals are screw-type, accepting 2 × (0.5...1.5 mm²) or 2 × (0.75...2.5 mm²) solid or stranded wire. The screwdriver tip required is Pozidriv PZ 2 with a shaft diameter of 5...6 mm.
Auxiliary contact ratings
The integrated auxiliary switch is rated for switching at several common control voltages: 2 A at 24 V, 3 A at 120 V, 2 A at 230 V, 1 A at 400 V, and 0.3 A at 60 V. These ratings cover both AC and DC control circuits typically found in motor control centers.