Metallics MWBC2218 #22--18 Wire Term Butt

The MWBC2218 is sized for 22 to 18 AWG stranded or solid conductor. If your conductor is 16 AWG or larger, this barrel will not grip it properly and you need the next size up in the butt connector range.

A butt connector like the Metallics MWBC2218 joins two wire ends to each other inline, crimped one conductor into each end of the barrel. A ring or fork terminal does something different, it puts a lug on the end of a single wire so it can land under a screw or stud. If you are splicing a run of 22 to 18 AWG control or signal wire, the butt is the right part; if you are terminating to a terminal block or device screw, you want a ring or fork terminal instead.

Yes, 22 to 18 AWG is the gauge band you find on thermostat wire, door and access control runs, alarm and signal circuits, so the MWBC2218 covers inline splices on that kind of work. It is a wire-to-wire splice only, so it is not a substitute for a device termination or for a junction inside a listed enclosure where your local code calls for one.

Use an insulated terminal crimper matched to the 22-18 AWG color range, not pliers and not a bare-terminal die. A proper crimp on both ends of the barrel is what makes the splice mechanically sound; crushing it with linesman pliers gives you a joint that pulls apart. Crimp one conductor per end, then tug-test each side.

Order Metallics MWBC2218. That is the single model covering the 22 to 18 AWG butt splice, so there is no finish, length, or size option to specify with it.