ABB 288B571A12 Directional Overcurrent Relay Unit

ABB 288B571A12 Directional Overcurrent Relay Unit, also marketed as the CR-7 120V Directional Unit, is a directional overcurrent protection module used in ABB protection schemes to sense current flow direction and trigger protective actions on fault conditions. Designed for 120V environments, this unit is intended to be part of a broader relay assembly, providing directional logic that determines whether a fault is flowing toward or away from the protected element—such as a feeder or bus—then issues a trip signal or enables a downstream protective action as defined by the protection scheme. The part number 288B571A12 identifies this specific directional relay unit within ABB's CR-7 family, a legacy model that has historically supported fast isolation and coordinated protection in substations and distribution networks. Common applications include protection of feeders, interties, and switchgear interconnections in electrical distribution systems, where directional overcurrent sensing helps prevent unnecessary disconnections and supports selective coordination with other protective devices.