The LC1F1250X7: The 1260 A AC-1 rating is the headline number — this contactor is sized for heavy resistive loads, not motor starting (AC-3). The 1000 A gG fuse recommendation at ≤ 440 V gives you the upstream protection limit. Plate mounting (not DIN rail) and 58 N.m power circuit torque tell you this is a bolted-down, high-force connection — expect busbar work, not screw terminals on the line side. The 8 kV rated impulse withstand voltage (Uimp) and overvoltage category III place it in fixed-installation distribution panels.
Integration notes
Plate mount, 255 mm deep, 309 mm wide, 338 mm tall — plan for a backplate footprint that clears adjacent devices. Power circuit bars accept 100 x 5 mm busbar; control circuit uses screw clamp terminals for 1-4 mm² flexible or solid. Tightening torque: 58 N.m on power, 1.2 N.m on control. The 20 W heat dissipation at rated load means forced ventilation in a sealed enclosure above 40 °C ambient. Operating altitude 3000 m without derating covers most installations.