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District 8 - Coal Mine Safety and Health
Info-Grams and Close Call Accidents


Info-Grams
Close Call Graphic Department of Labor
Mine Safety and Health Administration

Info-Gram
August 2000

Electrical Arc



A recent electrical accident occurred when an electrical foreman received serious burns to both hands and face from an electrical arc. The electrical foreman and an electrician replaced a 480-volt circuit breaker panel with a 1000-volt circuit breaker panel. After installing the 1000-volt circuit breaker panel, the 7200-volt transformer power was re-energized. Upon energizing the transformer, the AMR-type ground check circuit would not allow the newly installed 1000-volt circuit breaker panel to be energized. The electrician turned and started to look at the ground check relay to see if it was closed. At this time, an electrical arc occurred. After the smoke cleared, the electrician turned toward the electrical foreman and observed the 1000-volt circuit breaker panel leaning outward. The newly installed circuit breaker panel had been unbolted by the electrical foreman and the energized line side 995-volt connections had contacted the transformer frame. This produced the electrical arc, resulting in burns to the electrical foreman. The 7200-volt power to the transformer was tripped out by the transformer as the result of the short circuit.

BEST PRACTICES

  • Ensure that equipment is de-energized, grounded, and locked and tagged out before performing electrical work.
  • Use proper equipment (gloves, etc.) when performing electrical work.
  • Have proper qualifications and training before performing electrical work.

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This information was provided by concerned miners in an effort to eliminate accidents. Accident or "close call" information within District 8 may be shared by contacting the MSHA office at (812) 882-7617.