Toshiba Corporation RC81A Ground Fault Module

The Toshiba RC81A Ground Fault Module provides zero-sequence ground fault detection for three-phase motor control systems when used with Toshiba RC800 and RC820 Type 2E motor protection relays. Designed for installation in motor control centers, pump stations, compressors, conveyors, mining equipment, and water or wastewater treatment facilities, it delivers adjustable protection to guard motors and electrical gear against insulation failures and ground faults. Maintenance teams, OEMs, and system integrators frequently use the RC81A for replacing failed modules, upgrading motor protection, preventive maintenance, and control panel retrofits. Key specifications: MPN RC81A; Brand Toshiba; Product Type Ground Fault Module; Compatible Relay Series RC800 / RC820 Type 2E; Protection Function Zero-Sequence Ground Fault Detection; Ground Fault Current Setting 4–12 A (ZCT Primary); Maximum Ground Fault Current 60 A; Ground Fault Time Adjustment 0.1–1.0 seconds; Output Signal uses Basic 2E Relay Output Contacts; Trip Indication LED with Manual Reset; Zero Sequence Current Transformer (ZCT) rated 12 A primary, 40 mA secondary, 300 Ω connected impedance; Installation is a plug-in optional module for a 2E relay and Mounting in MCC or control panel. Applications include three-phase motor ground fault protection in industrial motor starters, HVAC, mining and chemical processing plants, and factory automation systems. Common replacements: RC81C; RC820-RC81A; RC800-RC81A.