Current Protection

2C74 Instantaneous Current Relay


This product is obsolete.

Consider the alternative 2C65 relay for your application.

Note that the 2C65 is not directly equivalent to the 2C74.


  • High speed operation
  • High sensitivity
  • 50Hz or 60Hz operation
  • Seven (7) current settings using a plug bridge
  • Choose from 5 setting ranges
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  • Hand reset mechanical flag
  • 2 N/O trip contacts
  • Rugged attracted armature sensing element
  • Use 3 independent units for 3 phase applications
  • Size 2M28 draw out case
  • Made in Australia


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.

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Railway rolling stock
Railway signalling