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High Voltage Procedures

In addition to the guidelines associated with general electrical safety and lockout/tagout procedures, there are more stringent safety requirements for high voltage procedures.

The following list provides high-voltage safety tips. For more information, please refer to OSHA Title 29 Section 1910.269 of the Code of Federal Regulations or NFPA 70 (National Electric Code).

  • Ensure that only authorized employees work around high voltage equipment.
  • Label entrances with a High Voltage Sign.
  • Ensure that terminal voltage ratings can withstand surges caused by electrical faults or switching transients.
  • Be careful around output circuits even when the input power is off. Parallel power sources and energy storage devices can still be dangerous.
  • Be careful when working with power supplies that serve more than one area.
  • Before working in a high voltage area, inspect the power supply and check all protective devices.
  • Do not work alone near high voltage.
  • Label equipment to identify power sources. Label input power sources to identify connected power supply loads.
  • Attach emergency shutdown instructions and phone numbers to equipment that is remotely controlled or unattended while energized.

Before entering a power supply or associated equipment enclosure to work on hazardous energy sources, complete the following:

  • De-energize the equipment.
  • Open and lockout the main input power circuit breaker.
  • Check for auxiliary power circuits that could still be energized.
  • Inspect automatic shorting devices for proper operation.
  • Short the power supply with grounding hooks.

May 2011
Revised November 2014