The Schneider Electric LP1K12004UD3 is a TeSys K contactor with 4 poles, all normally open (4 NO), rated for AC-1 resistive loads at 20 A operational current on a 690 V AC 50/60 Hz power circuit. The 250 V DC coil includes a built-in bidirectional peak limiting diode suppressor, so external flyback suppression on the control side is already handled — one less component to panel-mount. AC-1 utilisation category means this contactor is specified for resistive loads — heaters, lighting banks, or any load where the current inrush stays close to the steady-state value. For motor or inductive loads you would step to an AC-3 rated contactor; the LP1K12004UD3 is not the right pick for that duty.
The operational current (Ie) is also 20 A at 690 V AC-1, but derates to 16 A at ambient temperatures above 50 °C — so if the panel runs hot, size accordingly. Rated breaking capacity reaches 110 A at 440 V, 80 A at 500 V, and 70 A at 660–690 V per IEC 60947. That tells you the contactor can interrupt fault currents at those levels, not just carry them. Rated making capacity is 144 A AC for the power circuit. For high-speed switching applications like resistance welding controls or fast cycling heaters, that rate cap matters — sustained operation above it accelerates wear. The coil draws 3 W inrush and 3 W hold-in power at 20 °C. Control circuit voltage limits are 0.8–1.15 Uc for operational pick-up and 0.1–0.75 Uc for drop-out below 50 °C. The built-in diode suppressor handles the inductive kickback on the DC coil, so no additional snubber is needed across the coil terminals.
Depth is 57 mm, so account for that behind the panel door when wiring. Screw-clamp terminals accept Philips No 2 or flat 6 mm screwdrivers at 1.3 N·m tightening torque. Altitude derating starts above 2000 m.
Certified to EN/IEC 60947-4-1, UL 60947-4-1, CSA C22.2 No 60947-4-1, JIS C8201-4-1, and GB/T 14048.4. That covers the major global markets — IEC for Europe and Asia, UL/CSA for North America, JIS for Japan. Flame retardance is V1 per UL 94, and meets NF F 16-101/102 Requirement 2 for rail applications. Rated insulation voltage (Ui) is 690 V per IEC 60947-4-1 and 600 V per UL 508 / CSA C22.2 No 14. Impulse withstand voltage (Uimp) is 8 kV, which is standard for overvoltage category III installations.