Sta-Kon C221 UNINS LKG FORK TERM 12-10 No8

The C221 is sized for 12-10 AWG conductor. That is a single barrel covering both gauges, so a panel built with a mix of 12 and 10 AWG branch wiring can be terminated with one part number and one crimp die. Anything 14 AWG or smaller needs a different barrel size, since an undersized conductor in a 12-10 barrel will not hold a mechanically sound crimp.

It is built for a No. 8 screw or stud. The fork slot slides in around a No. 8 terminal screw that is already partly backed out, so you are not pulling the screw all the way out of a crowded terminal block or contactor to land the wire.

Non-insulated. The C221 is bare copper with no nylon or vinyl sleeve, so once it is landed you have exposed metal at the crimp barrel. That is normal inside an enclosure, a terminal box, or under a terminal strip cover, and it is what you want when heat shrink is being applied over the joint or when terminals are packed tightly and an insulating sleeve would not fit. For an open or accessible termination where accidental contact is possible, use an insulated fork terminal instead.

A fork terminal goes on and off without removing the screw, which is why it is the common choice on control panels, relay bases, and terminal strips where you are troubleshooting and reterminating. A ring terminal is captive and cannot vibrate off the stud, so it is preferred on motor leads, grounding studs, and anything subject to vibration. The locking tangs on the C221 are the compromise: the fork bites under the screw head so it resists backing out while still letting you drop the wire off a No. 8 screw.

It is covered under UL file E9809, which is the reference an inspector or a spec reviewer will want on an institutional or government job. The terminal is also made in the United States, which matters where domestic-sourcing language appears in the purchase order.

Non-insulated terminals crimp on the bare-barrel nest of a terminal crimper, not the color-coded insulated nests, and the correct nest is selected by the 12-10 AWG barrel size. Pliers will deform the barrel without forming a proper indent and will not give a reliable mechanical or electrical connection on a 600 V circuit. Order the part number C221 and set your tool to the bare 12-10 position.

No. The C221 barrel is copper and is intended for copper conductor. Aluminum branch or feeder wire requires a terminal rated AL or AL9CU with the appropriate inhibitor compound, and putting bare copper on aluminum invites a galvanic problem at the joint.