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SMTB4 Compact IEC Test Block and Test Plug System

Product Announcement from GE Digital Energy

SMTB4 Compact IEC Test Block and Test Plug System-Image

GE's SMTB4 is a 4-pole compact IEC test block and test plug system designed to isolate protection relays and other secondary devices from voltage and current sources, and to allow functional testing of power equipment without interruption of service. Current and voltage block and plug assemblies are available with a several mounting and wire termination options.

Key Benefits

  • Flexibility and features to meet electrical utility and industrial requirements for safe, reliable and efficient testing
  • Enables the testing of protection relays and meters with no interruption of the power circuit
  • Reduces man-hours for testing and trouble-shooting
  • Compact size with multiple mounting and wiring provisions
  • Designed and qualified for the unique needs of the protection and control industry
  • Advanced security, robustness and reliability in harsh industrial environments
  • No disruption to existing connections or relay settings needed for testing purposes

Key Features

  • Color coded to differentiate between current and voltage circuits
  • Test plug for safely shorting current circuits before isolating current operated devices
  • Surface, flush, semi-flush and G32 DIN rail mounting provisions
  • Locking system for securing plug to base
  • Easily identifiable "Live" and "Equipment" test sockets
  • Space saving compact design
  • Designed for harsh industrial environments
  • Front (surface, semi-flush, and DIN rail) and rear (flush and semi-flush) access wiring
  • Screw clamp, ring tongue, and quick connect termination provisions for up to 2.5 mm² wire
  • CE, RoHS, and REACH certified


  • Isolate relays and meters from instrument transformers and inject current/voltage into the devices to quickly and safely verify system protection and measurement performance
  • Automatically short CT secondaries with use of available test plug with internal CT shorting links
  • Calibrate meters and control devices
  • The Test Plug can be connected continuously to the Test Block in order to supply current or voltage to secondary circuit sub-assemblies
  • Perform testing on up to four independent circuits on one test block
  • Measure output of CT's and VT's with or without disconnecting devices from the circuit