The 2C74 relay provides high speed overcurrent protection for various items of power system plant such as frame earth leakage protection of metal clad switchgear & tank earth fault protection of sub-station power transformers. The 2C74 relay is a single phase device built in a compact size 2M draw out case suitable for rack and flush mounting. Where 3 phase monitoring is required, 3 single phase units should be employed. The relay measuring element is basically an attracted armature unit of simple & rugged construction. The operating coil of this unit is energised from a transformer which is tapped to provide seven (7) current settings. Setting is achieved using a plug bridge arrangement on the front panel.