What this contactor is and where it fits
The Siemens 3RT1025-1BE40 is a SIRIUS S0-frame power contactor rated for motor switching up to 11 kW at 690 V AC-3 and 10 kW at 500 V. It carries a 24 V DC coil with a steady holding power draw of 5.4 W. The S0 frame size — 45 mm wide, 85 mm tall, 101 mm deep — makes it a standard fit across motor control centres and panel layouts that use the 35 mm DIN rail per DIN EN 50022. The AC-3 rating is the one that governs most induction-motor duty; the 11 kW at 690 V figure tells you the contactor can handle a full-voltage start and run of a motor in that power band. For reversing or plugging duty (AC-4), the rated current drops to 15.5 A at 400 V — the higher switching frequency and inrush on reversal means the contactor derates from its AC-3 capability.
Mounting and panel integration
The contactor snaps onto a 35 mm standard mounting rail and can also be screw-mounted. Side-by-side mounting is permitted, which matters when you are packing multiple contactors into a row — the S0 width of 45 mm per unit sets the fill factor. A 6 mm clearance at the side is required for heat dissipation and arc containment. The front face carries an IP20 rating; the terminal area is rated IP00. That means the front is touch-safe for panel builders, but the terminals themselves are not finger-safe once the gland plate is open — standard for this class of contactor. Pollution degree 3 confirms it is rated for industrial environments with conductive dust or occasional condensation.
Coordination and protection
For Type 2 coordination (no damage to the contactor after a short circuit) the required upstream fuse is gL/gG 25 A. Type 1 coordination (contactor may need replacement after a fault) allows a 63 A gL/gG fuse. These are the values a panel builder needs to set the branch-circuit protection — oversize the fuse and you lose the coordination the contactor was tested for.
Lifecycle and sourcing reality
The lifecycle stage is listed as current, meaning Siemens continues to manufacture this order code as an active catalogue item. For a BOM that needs this exact S0 contactor with the 24 V DC coil, the part is in standard production and can be specified without concern for imminent phase-out. Sourcing is straightforward for an active Siemens SIRIUS line item. We quote the 3RT1025-1BE40 to order against an RFQ, with availability and current pricing confirmed at quote time. If you hold a panel that originally specified a different S0 contactor — say the 3RT1023-1AL20 — the 3RT1025-1BE40 shares the same S0 frame and DIN-rail footprint, but verify the coil voltage and power ratings match your load before swapping.
Terminal wiring details
Main current circuit terminals are screw-type. They accept solid conductors from 2x 0.5 mm² up to 2x 4 mm², and stranded conductors from 2x 1 mm² up to 2x 10 mm². AWG equivalents run from 2x 16–12 down to 1x 8 for the main contacts. This covers most panel wiring from control-circuit tails to motor-feed cables within the S0 contactor's rating.