The LC1K12004D7 is a 4-pole (4 NO) TeSys K contactor from Schneider Electric, designed for resistive load switching in control circuits. It carries a conventional free-air thermal current (Ith) of 20 A at 50 °C and an AC-1 rated operational current (Ie) of 20 A at ≤440 V, with a 42 V AC 50/60 Hz coil. The 4 NO pole configuration means all four poles are normally open — no auxiliary NC contacts on board — so plan for external auxiliary blocks if your circuit needs a held-closed feedback signal.
The AC-1 utilisation category rating (20 A at ≤440 V) tells you this contactor is built for resistive loads — heaters, lighting banks, or transformer primaries — not for motor starting (that would be AC-3). For motor duty you'd need a different TeSys K variant. The 42 V AC coil is common in control transformers on older or site-isolated panels; verify your control voltage matches because the coil hold-in range is 0.8 to 1.15 Uc (33.6 to 48.3 V) and drop-out is 0.2 to 0.75 Uc (8.4 to 31.5 V) below 50 °C. Heat dissipation is 1.3 W at the coil's hold-in power of 4.5 VA — negligible for most enclosures, but worth noting if you're packing multiple contactors into a sealed panel. The mechanical robustness specs (10 Gn shock on Y/Z axes when closed, 4 Gn vibration 5–300 Hz) mean it holds in under moderate industrial vibration, typical for conveyor or pump panels. Safety reliability is documented with B10d values: 1,369,863 cycles under nominal load and 20,000,000 cycles under mechanical load per EN/ISO 13849-1. That's useful if you're calculating MTTFd for a safety-related control circuit.