Critical Power Services: Arc Flash Analysis

conductors or the air between a grounded conductor and an ungrounded conductor. Arc faults can occur when as little as 120 volts are present, but arc flashes that result from medium and high voltage switchgear involve dangerous amounts of energy that could cause critical injuries. In a facility's switchgear, the power source for an arc flash is always present. Securing the right maintenance services, particularly arc flash analysis, can deter their occurrence.

Arc Flash Statistics

The U.S. Department of Labor reports that 2,000 electrical workers are admitted to burn units each year with serious arc flash injuries. As for what defines a serious arc flash injury financially, CapSchell, a Chicago based research and consulting firm, notes the total cost of a serious electrical injury can approach $10 million. A company's insurance carrier can shoulder most of that cost, but the ensuing rise in insurance premiums could be painful.

Considering the injuries that arc flashes could cause workers and the financial difficulty those injuries can cause employers, facility managers should take every opportunity to prevent arc flashes. When they do, they hire a power service to perform the following measures on a set schedule:

  • Check the switchgear for loose terminations
  • Check for debris and dust build up on internal switchgear components
  • Test the switchgear for stored energy
  • Check for proper system design and modifications
  • Examine the design of switchgear housing


In addition to receiving the critical power services above, the switchgear in an Emergency Power Supply System (EPSS) should be tested annually according to National Fire Protection Association (NFPA) code 70E. This test is often performed in conjunction with NFPA 110 monthly generator testing.

Additional Safety Measures

In addition to setting testing guidelines for switchgear that isolates an EPSS, NFPA 70E also establishes guidelines for the Personal Protective Equipment (PPE) electrical workers should wear when they service the equipment. NFPA 70E bases PPE guidelines on the incident energy level of switchgear, which is expressed as calories per centimeters squared. There are four hazard levels requiring different types of PPE:

  • Level 1  - Fire Resistant (FR) shirt and pants
  • Level 2  - Cotton underwear and FR shirt and pants
  • Level 3  - Cotton underwear, FR shirt and pants, and FR coveralls
  • Level 4  - Cotton underwear, FR shirt and pants, and multilayer flash suit


Facilities should also protect workers by posting warning labels on switchgear that indicate its hazard level and the type(s) of PPE they must wear when accessing it.

Does Your Facility Need Arc Flash Analysis?

Arc flashes happen in an instant, but the damage it could cause could take years for the injured victim and his or her company to recover. Prime Power can help keep your company and its workers from being in this position by performing arc flash analysis on its switchgear.

For over twenty-five years, Prime Power has performed arc flash analysis, NFPA 110 generator testing, infrared scanning, scheduled maintenance, and other critical power services that are essential to the efficiency, reliability, and safety of a facility's electrical system. Call us today for a free consultation on arc flash analysis.