What it is and where it lands
The Siemens 3RT2526-2AB00 is a SIRIUS S0 contactor with spring-type terminals — no screw torque, no loosening over vibration cycles. Coil pulls 24 V at 50 Hz. Rated for 10 A at 24 V AC/DC and 3 A at 400 V. That covers control transformers, small motor loads, and resistive heater banks inside a panel. Mounts via screw or snap-on onto 35 mm standard mounting rail per DIN EN 50022. Mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward. Side-by-side mounting is supported with zero spacing.
Ratings that drive the fit
The AC-1 maximum switching frequency is 1 000 operations per hour; at DC it's 1 500 per hour. Arcing time is 10 to 10 ms — consistent, predictable break. Mechanical endurance is 10 000 000 cycles typical. Operating temperature spans -25 to +60 °C; storage from -55 to +80 °C. That -25 °C floor is important: if your panel sits in an unheated space in a cold climate, this contactor starts and holds without a heater.
Termination and wiring
Spring-type terminals accept solid or stranded conductors 2x (0.5... 2.5 mm²). No screwdriver torque check — push in, release, done. The auxiliary switch is built in, so no add-on block needed for basic status feedback. This saves a DIN-rail slot and one wiring step.