Metallics MWRC121056 #12--10 Wire Term Ring 5/16-St

The MWRC121056 ring terminal is sized for #12 to #10 AWG stranded conductor. Running it on wire outside that range, either smaller than #10 or larger than #12, gives you a barrel that won't crimp to a reliable mechanical hold.

A ring terminal like the Metallics MWRC121056 is the closed-barrel choice: the connection can't vibrate off the screw without the screw being backed all the way out, which is why rings are specified for grounding, motor terminals and anything that moves. A fork or spade terminal slides out sideways and is faster to service, so electricians use it where terminations get swapped often. For a 5/16 inch stud on a ground bar or equipment lug, the ring is the one to use.

Yes, it is a crimp-on terminal, not a screw-down connector. It needs a terminal crimper matched to the #12 to #10 AWG barrel range. Pliers or a cutter's crimp notch will deform the barrel without forming a proper cold weld, which is the usual cause of a hot termination on a motor or ground connection.

It is called out as a stranded-wire terminal for #12 to #10 AWG. Crimp barrels are built around stranded conductor, which compacts under the crimp. Solid wire does not deform the same way and tends to back out of the barrel, so for solid conductor you want a terminal rated for it or a different termination method entirely.

Metallics part number MWRC121056. One model covers the #12 to #10 AWG stranded range with the 5/16 inch ring, so there is no size or finish option to specify when ordering.