Sta-Kon RC4 YELLOW POLYCARBONATE RNG TRM

The RC4 is sized for 4 to 6 mm2 conductor, which in AWG terms covers roughly 12 and 10 gauge wire. If your conductor is smaller than 4 mm2 the barrel will not grip properly after crimping, and anything above 6 mm2 will not seat in the barrel at all, so step to the next larger terminal in those cases.

Electrolytic copper is the conductor material on the RC4, so it is for copper conductors and copper-to-copper terminations. Do not use it on aluminum building wire, which needs a terminal rated and listed for aluminum or AL/CU service.

Yellow is the wire-range code on insulated terminals, and on the RC4 it identifies the 4 to 6 mm2 barrel. It is a quick field check: an electrician pulling a yellow terminal from the bin knows it is the heavier of the common insulated sizes, above the red and blue ranges. The color is in the insulation itself, not a printed mark, so it stays legible in a panel.

A ring terminal like the RC4 is a closed barrel: the stud has to be removed to get the terminal off, so it cannot vibrate or pull loose off the screw. That is what you want on motor terminals, grounding studs, bus bar connections and anything in a vibrating environment. A fork or spade slips on and off under a loosened screw, which is faster for service work on terminal blocks you expect to open repeatedly but less secure on a stud.

Yes, use a crimper made for insulated terminals, with the die nest matched to the yellow 4 to 6 mm2 range. An insulated-terminal crimper compresses the barrel through the polycarbonate sleeve without cutting it. A bare-terminal or non-insulated die will split the insulation, and pliers will not produce a mechanically sound crimp. No tool is supplied with the terminal.

Polycarbonate, not vinyl. That matters on a crimp sleeve because polycarbonate resists cracking and splitting when the barrel is compressed and holds its shape better at elevated panel temperatures than a soft vinyl sleeve. The insulation covers the barrel; the ring tongue is bare for contact under the stud.

Order it as Sta-Kon RC4. That is the manufacturer part number for the yellow polycarbonate insulated ring terminal in the 4 to 6 mm2 wire range, and it is the only model on the item, so there are no finish or size options to specify. Country of origin is Sweden, which procurement teams often need for documentation.