What the 3 A contact rating means for your circuit
The XCKM121H7 is rated 3 A at 240 VAC and 0.27 A at 250 VDC — that's the maximum continuous switching current, not the inrush. For a typical 120 VAC control circuit pulling a small relay coil (say 0.5 A holding), you've got headroom. But if you're switching a DC solenoid or a brake, the DC rating drops fast because DC arcs don't self-extinguish the way AC does. The 0.27 A at 250 VDC is the hard ceiling — stay under it or the contacts weld shut. The 1NO-1NC contact configuration gives you one normally-open and one normally-closed set in the same switch body. That lets you wire the NC as a safety feedback (opens when the lever is tripped) and the NO as a position signal to the PLC — all in one package without a second switch.
Mechanical fit: pretravel, differential, and operating force
The thermoplastic roller lever plunger is the wear point — the roller reduces friction against the cam surface, so it lasts longer than a plain plunger in high-cycle applications. The ZAMAK zinc alloy body handles the mechanical abuse of a machine frame or conveyor edge.
Approvals and compliance documentation
The XCKM121H7 carries UL 508, CSA C22.2, and CE approvals — that covers North American and European machinery safety standards. It also references EN/IEC 60204-1 (electrical equipment of machines) and EN/IEC 60947-5-1 (control circuit devices). These are the standards a panel builder or machine integrator needs to see for a CE declaration or UL 508A panel listing. Proposition 65 warning applies — the product contains DINP and DIDP, which are phthalates used in the plastic components. That's a California labeling requirement, not a functional restriction.