What this contactor is and where it fits
The Siemens 3RT1026-1AU60 is a SIRIUS power contactor in the S0 frame size, built for switching three-phase motor loads in control panels. It carries three normally-open main contacts and lands on a 35 mm DIN rail per EN 50022 via screw or snap-on mounting — the 45 mm width is the standard S0 footprint, so it slots into a pre-drilled panel layout without surprises.
What the ratings mean for the buyer
The AC-2 rating at 400 V is 11 kW — that is the duty for slip-ring motor starting, where the contactor makes and breaks under load but at reduced current peaks. For AC-4 (inching/plugging) at 400 V the rating drops to 15.5 A, reflecting the higher electrical wear from frequent make-break cycles. The AC-12 maximum operating current of 10 A covers resistive loads like heater banks. These are the numbers that govern the real selection, not a single headline current. Termination is screw-type on the main circuit, accepting solid conductors from 2x 0.5 mm² up to max 2x 4 mm², and stranded from 2x 1 mm² up to max 2x 10 mm². That covers most panel wiring up to the 35 A fuse required for Type 2 coordination (gL/gG) or the 100 A fuse for Type 1. The pollution degree 3 rating means it is suited for industrial environments where conductive dust or condensation can occur — no derating needed for typical panel conditions. Operating temperature spans -25 to +60 °C, which covers most indoor panel applications without a heater or forced cooling. Front face carries IP20 — safe from finger contact — while the terminal area is IP00, so live parts are exposed once the cover is off. Side-by-side mounting is allowed (zero gap), which saves rail space when multiple contactors share a common bus. Mechanical endurance is rated at 10 million operations typical — that is the contactor body itself, not the contacts under load. Electrical life will be lower and depends on the switching duty (AC-2 vs AC-4) and the actual current switched.
Panel integration notes
At 45 mm wide, 85 mm tall, and 91 mm deep, the S0 envelope fits a standard 4-module DIN-rail pitch. The 91 mm depth is the dimension from the mounting rail to the furthest projection — check that against your enclosure depth, especially if a door-mounted operator or busbar shroud sits behind the contactor. Screw terminals on the main circuit; auxiliary contact blocks (not included) snap onto the front or side without increasing the width beyond the S0 frame.