The Siemens 3RB3026-1SB0-ZX95 is a SIRIUS solid-state overload relay in size S0, designed to protect AC motor circuits against overload and phase failure. The integrated auxiliary switch provides a dedicated normally-closed contact for the tripped message — meaning the relay signals a fault condition via the 97/98 terminals without needing an external aux block.
Rated thermal current (Ithe) is 12 A, and the trip class is CLASS 10E — the relay will trip within 10 seconds at 7.2× the current setting, making it suitable for standard motor starting duty on pumps, fans, and conveyors where the start-up transient is brief.
Fastening method is contactor mounting — it clips directly onto a SIRIUS contactor (size S0), saving DIN-rail space and reducing wiring between the relay and the contactor coil. The auxiliary switch is integrated, so no separate aux block is needed for the tripped signal. Screw terminals accept 1x (0.5 to 4 mm²) solid or 2x (0.5 to 2.5 mm²) stranded per pole; main circuit terminals accept up to 2x 10 mm² stranded.