The ABB KC6‑31Z‑05 is a compact 4‑pole mini‑contactor relay (mini contactor) designed for control‑circuit switching and light to moderate loads. It uses a DC‑operated coil (for this “‑05” version), making it suitable for control from DC sources such as PLC outputs or DC logic circuits. The unit is built for applications where space is limited but reliability is required — for example control panels, automation equipment, residential or commercial building control, and industrial control circuits. The coil is “hum‑free / noiseless”, giving quiet operation; the unit uses screw terminals and can be DIN‑rail or panel mounted. Because of its small size and compact 4‑pole configuration, it is also useful for switching multiple lines (e.g. three‑phase plus neutral) or multi‑circuit control in compact switch boxes.