Sta-Kon F2027 INS PP FERRULE 18-17, 1 MM2, LG .4

The F2027 insulated wire ferrule is sized for 18-17 AWG conductor, which is the 1 mm2 metric equivalent called out in its description. If you are terminating stranded control wire at 1 mm2, this is the one. Larger conductors need a bigger ferrule, not this one crimped loose.

Red is the insulation color on the F2027 ferrule, and on ferrules color is the field shortcut for wire size. On a panel with mixed control wiring, the red collar lets an electrician or inspector confirm a 1 mm2 / 18-17 AWG termination without pulling the conductor or reading the crimp.

The crimp barrel is copper with a polypropylene insulating sleeve. Copper is what makes it suitable for terminating copper stranded conductor without a dissimilar-metal junction, and it is what lets the crimped barrel hold up under a terminal block screw instead of letting loose strands spread.

It has to be crimped. The F2027 is a copper barrel with a polypropylene entry sleeve, and the mechanical and electrical connection comes entirely from compressing that barrel onto the strands. A ferrule crimper (square or trapezoidal die sized for 1 mm2 / 18-17 AWG) is required; pliers will not give a repeatable crimp and the wire can back out of a terminal block.

A ferrule like the F2027 is the right choice when the conductor lands inside a clamping terminal block, breaker, or drive terminal, because it gathers the strands into a solid pin that the screw can compress without splaying or cutting strands. A fork or ring terminal is for landing under a screw or stud instead. For 1 mm2 / 18-17 AWG panel and machine wiring going into cage-clamp or screw-clamp blocks, the ferrule is the one spec'd.

Order it as Sta-Kon F2027. It is manufactured in Germany, which is worth knowing if your project paperwork requires a country-of-origin declaration on installed components.