The Siemens 3RB2026-2SB0-ZX95 is a SIRIUS solid-state overload relay — a three-pole device that protects motor circuits against overload and phase failure by monitoring current and tripping on a CLASS 20E curve. That CLASS 20E rating means it allows up to 20 seconds of locked-rotor current before tripping, matching the thermal characteristics of standard AC induction motors. It mounts directly onto a contactor, saving panel space, and carries ATEX Ex II (2) GD certification for use in potentially explosive atmospheres — the (2) indicates it can be installed in the safe area but protects equipment in Zone 1/21 or Zone 2/22 gas/dust environments. The auxiliary circuit provides one normally-closed contact rated for switching: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and 0.55 A at 60 V, among other voltages — so it can directly signal a PLC input or drop out a holding circuit across common control voltages without an interposing relay. The main circuit uses screw-type terminals accepting 0.5 to 4 mm² solid or 0.5 to 2.5 mm² finely stranded with ferrules; auxiliary terminals accept 2x 0.5 to 2.5 mm² solid or 2x 0.5 to 1.5 mm² stranded.
Ruggedness and environmental tolerance
It withstands 15 g shock over 11 ms and surge voltages up to 6 kV, with EMC burst immunity at 2 kV on power ports and 1 kV on signal ports per IEC 61000-4-4 severity level 3. Mounting position is unrestricted, and the 45 x 73 x 75 mm footprint (width x height x depth) fits standard 45 mm-wide DIN-rail contactor assemblies.
The 3RB2026-2SB0-ZX95 is listed as a current-production item within the SIRIUS portfolio. No official replacement has been announced; the part remains the direct fit for new builds and spares requiring a contactor-mounted solid-state overload with CLASS 20E and ATEX certification.