The Siemens 3RT1034-1AU04 is a SIRIUS power contactor in the S2 frame, designed for motor switching and general load control in industrial panels. It mounts on 35 mm DIN rail per DIN EN 50022 and uses screw-type terminals for the main circuit — a straightforward fit for a standard panel layout, no special adapter needed. The front face carries an IP20 rating, meaning the operator interface is finger-safe; the terminal area is IP00, so live parts are exposed once the panel door opens. That's normal for this class — the panel enclosure provides the overall protection.
Key ratings and what they mean for fit
The headline motor-switching number is 29 A at 400 V in AC-4 duty — that's the severe inrush from plugging or inching a motor, not just running it. If your application involves frequent reversing or jogging, this is the rating that governs contactor life. For standard motor starting (AC-3), the contactor handles 15 kW at 400 V, and it's rated 18.5 kW at 500 V and 10 kW at 690 V. Those numbers tell you the contactor is sized for a 15 kW motor on a 400 V line, with headroom for higher-voltage, lower-current loads. The AC-2 rating (slip-ring motor starting) is 15 kW at 400 V. Auxiliary contact ratings cover 24 V at 10 A, 60 V at 2 A, 110 V at 1 A, 230 V at 6 A, and 400 V at 3 A — enough for most control-circuit loads, but check your coil inrush if you're driving multiple contactors from one aux.
Environmental and compliance
Rated for pollution degree 3 — that's the typical industrial environment where conductive dust or condensation can occur. Operating temperature spans -25 to +60 °C; storage range is -55 to +80 °C. The contactor carries a substance prohibition date of 05/01/2012, which aligns with RoHS compliance. No UL or CSA marks are listed in the spec record, so verify local code acceptance if your panel requires those approvals.
Wiring and mounting
Main circuit terminals accept solid wire from 2x 0.5 to 1.5 mm² up to 2x 0.75 to 4 mm², and stranded wire from 2x 0.75 to 25 mm². Minimum cross-section at 40 °C is 16 mm². That covers most panel wiring up to about 6 AWG. The S2 frame is 55 mm wide, 112 mm tall, 164 mm deep — a compact footprint that leaves room for adjacent devices. Side-by-side mounting is allowed, so you can gang multiple contactors without spacing gaps.