Form factor and socket mount
The Omron MJN2CK-AC120 is a compact enclosed DPDT relay in the MJN series, socket-mounted on a 9-pin octal-style base with a C socket code. It drops into a panel like any other octal relay — the pin terminals are the only electrical connection, and the relay body is keyed against mis-mating. A manual push-to-test button on the top face lets the commissioning engineer exercise the armature by hand before energizing the coil, which speeds the FAT/SAT loop on any line that needs the relay proven out before the field wiring is live.
Coil, contacts, and what the 10 A actually means
The coil is rated 120V AC nominal at 60 Hz, which is the standard North American control-transformer secondary — the relay can be wired directly across a 120 VAC control bus without an interposing relay. Contact rating is 10 A at 240V AC and 10 A at 28V DC, both under the resistive ceiling — the DPDT form lets the same device switch a pair of loads or a reversing pair from one coil. It is motor-rated, with a 1/3 hp rating at 120V AC and 1/2 hp at 240V AC, which means it will switch small fractional-horsepower motor loads (fans, small pumps, solenoid-actuated valves) directly without an interposing contactor. Dielectric strength is greater than 2,500V AC RMS between mutually insulated elements and greater than 750V AC RMS across the open contacts — adequate for industrial control-panel environments where the relay sits near higher-voltage wiring.
Electrical and mechanical life for the BOM planner
Electrical operating durability is 100,000 cycles and mechanical operating durability is 10,000,000 cycles, the typical 100:1 ratio between unloaded mechanical life and loaded electrical life that defines a relay's maintenance interval. No status indicator is fitted — coil state has to be read at the socket or downstream, so for cabinets where visual state matters a parallel indicator lamp or an auxiliary output is the usual fix.
Sourcing posture and lifecycle
Lifecycle stage is recorded as mature on the manufacturer's part record.