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National Electric Energy Testing, Research & Applications Center
CONNECTOR EVALUATION

Heat Rise. . . . . Current Cycle . . . . . Failure Analysis

OVERVIEW

Connector reliability is essential to the operation of a utility transmission and distribution system. To help utilities and their suppliers assure the integrity of connectors used by utilities, NEETRAC maintains extensive test equipment for evaluating a wide variety of connectors used on electric utility systems – from meter base spade jaws to high tension sleeves used on large conductor transmission lines.

100 Cycle Submersion Test (Typical)

Performance Tests:

  • ANSI/NEMA C119.4 American National Standard for Electric Connectors, Connectors for Use Between Aluminium-to-Aluminium or Aluminium-to-Copper Bare Overhead Connectors
    • Current cycle submersion (accelerated 100-cycle alternative to ANSI C119.4, 500-cycle
    • Heat-cycle tests (500 cycle)
    • Conductor pullout strength
    • Conductor damage
    • Torque strength
  • UL 486B Wire Connectors for Use With Aluminium Conductors
    • Heat cycle
    • Static heating
    • Wire disturbance
    • Dielectric withstand voltage
    • Tightening torque
  • UL 411 Standard for Meter Sockets
    • Temperature
    • Dieletcric withstand

Combined Heat Cycle and Tension Test

  • IEEE 404 Standard for Cable Joints for Use Withj Extruded Dielectric Cable Rated 5kV Through 46kV and Cable Joints for Use With Laminated Dielectric Cable Rated 2kV Through 5000kV
    • Partial discharge voltage level
    • Short-time current
    • Cyclic aging
    • High-voltage time
500 Cycle Overhead Test (Typical)

Inhibitor Evaluation

  • Compatability with lineman's rubber safety equipment
  • Thermal stability
  • Electric resisitivity vs. temperature and pressure

Physical Examination

  • Hardness (Rockwell and Microhardness
  • Connector-conductor contact surface area
  • Connector cross-sectional area
  • Force-to-crimp compression connector evaluation
  • Stripping torque (bolted connectors)
  • Torque retention (bolted connectors)
  • Crimp down

FAILURE ANALYSIS

Example of Failure Analysis

Failure analysis and investigation is a powerful tool for improving the reliability of an electric energy transmission or distribution system. Systematic examination of a field or laboratory failure can identify the possible causes and conditions contributing to the root cause of the failure. NEETRAC has the equipment and the experienced personnel to perform thorough failure investigations.

  • Reliability evaluation of existing products based on known failure modes
  • Improved installation techniques and procedures
  • Techniques to identify products in the process of failure
  • Enhanced preventative maintenance programs
  • Development of repair procedures to prevent further damage
  • X-ray and dissection
Another Example of Failure Analysis

Last revised on November 29, 2011