What it is and what it does
The Siemens 3RT1026-1AG20-ZX95 is a SIRIUS power contactor in the S0 frame size, designed for switching motor loads in industrial control panels. It mounts via screw or snap-on onto a 35 mm DIN rail per EN 50022, fitting into a standard panel layout. The coil is rated for 110 V at both 50 Hz and 60 Hz, with an operating range of 0.8 to 1.1 times rated voltage at 50 Hz and 0.85 to 1.1 at 60 Hz — so it holds in during brownout conditions down to about 88 V at 50 Hz. For motor switching duty, the AC-4 rating at 400 V is 15.5 A, which covers frequent inching or plug-reverse applications where the contactor makes and breaks stalled-rotor current. The AC-2 rating at 400 V is 11 kW, suited for slip-ring motor starting. Main terminals are screw-type, accepting 2x (1 to 2.5 mm²) solid or stranded, up to 2x 10 mm² maximum. Auxiliary terminals accept 2x (0.5 to 1.5 mm²) solid, up to 2x (0.75 to 4 mm²). This is a standard wiring range for S0 contactors — no special crimping tools needed.
Ratings that decide fit
The 3RT1026-1AG20-ZX95 carries a mechanical life of 10 million operations typical, which is the standard for this frame size. Electrical life depends on the switching duty — AC-4 at 15.5 A will wear the contacts faster than AC-3 at the same current. Short-circuit coordination: with Type 2 assignment (no welding), the required fuse is gL/gG 35 A. With Type 1 coordination (welding allowed but no fire risk), the fuse can be gL/gG 100 A. This matters when sizing upstream protection for a motor branch circuit. The contactor is rated for operation up to 2,000 m altitude without derating, and ambient temperature range is -25 to +60 °C during operation. Pollution degree 3 means it's suitable for industrial environments with conductive dust or condensation — typical for a non-sealed panel. Front protection is IP20 (finger-safe), terminal area is IP00 (no protection). Side-by-side mounting is permitted with zero clearance, saving panel width — the 45 mm width stacks tightly.
Auxiliary contact block
This variant ships with zero factory-fitted auxiliary contacts (instantaneous contact count: 0). The S0 frame accepts add-on auxiliary contact blocks that snap onto the front or side. If your circuit needs N.O. or N.C. feedback, budget for a separate block. When adding auxiliaries, the contact ratings are: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 0.3 A at 220 V DC. These are the switching limits for the auxiliary circuit — don't expect the same current at higher voltages.