What the ratings mean for fit
The Siemens 3RT1476-6SF36 is a SIRIUS size S12 contactor — the largest frame in the SIRIUS contactor family, built for switching heavy motor loads in industrial control panels. Its MTBF of 75 a means the design target is one failure per 75 years of continuous operation, a figure that aligns with high-availability lines where unplanned downtime costs megawatt-hours on the meter. The coil accepts 96…127 V AC/DC, so a single control transformer or battery-backed DC bus covers both AC and DC installations without a separate coil variant. Power wiring is handled through screw-type terminals accepting stranded cable from 70 up to 240 mm² — sized for the full rated current of the S12 frame. The contactor mounts on a vertical surface with ±90° rotation and ±22.5° tilt, giving panel builders flexibility to fit tight enclosures without derating.
Integration into the panel
At 225 mm depth, 160 mm width, and 214 mm height, the S12 frame occupies significant panel real estate — plan for a minimum 10 mm clearance at the side, 10 mm upwards, 20 mm forwards, and 10 mm downwards for arc flash and cooling. The auxiliary switch is included, so no separate add-on block is needed for status feedback to the PLC. Operating temperature range of -25…+60 °C covers most indoor industrial environments; storage range of -55…+80 °C handles unheated warehouses. The screw fixing method uses an 11 mm hole — standard for M10 or 3/8-inch hardware.