NFPA  70E and Electrical Safety in the Workplace

A great topic to start the New Year is one concerning employee safety – specifically electrical safety in the workplace.  The National Fire Protection Association (NFPA) has developed an excellent standard on the topic – NFPA 70E.  (The National Electrical Code better known as the NEC is another product of the NFPA.)  While ‘arc flash’ concerns play a huge role in the 70E standard, it is so much more.  It also provides guidelines on items including shock hazards, equipment labeling, maintaining circuit protection equipment, developing an electrical safe work practices document, and defining qualified and task-qualified personnel.  A company that seriously incorporates NFPA 70E into its safety program will reap the benefits of a safer workplace and a greater understanding of its electrical system and hazards. 

According to the IEEE, ‘Each year, 2000 workers are admitted to burn centers for extended injury treatment caused by arc flash. Arc flash is an electric current that is passed through the air when insulation or isolation between electrified conductors is not sufficient to withstand the applied voltage’.  The temperature of an arc flash exceeds 35,000 degree F which is 4 times that of the sun’s surface.  All known materials vaporize at this temperature – copper expands 67,000 times. An arc flash can cause burns, shrapnel injuries, loss of sight and hearing, and blow workers off ladders and lifts and into physical structures.  Many arc flash incidents do result in workers deaths.  Causes of arc flash include dripping water, workers dropping tools, dust or chemical build-up, and improperly specified gear.  Beginning in January of 2009, OSHA requires specific employers to conduct hazard assessments according to 29 CFR 1910.132(d)(1). While OSHA does not, per se, enforce NFPA 70E; it does recognize it is has an industry standard.

There has been the risk of arc flash since the advent of commercial electricity, so why a new standard at the beginning of the 21st century?  There are several noteworthy reasons.  First, the understanding of arc flash has increased significantly.  Good empirical calculations have been developed to adequately quantify arc flash energy.  Second, personnel are more often exposed to arc flash hazards and those hazards are increasing with the capabilities of power distribution systems.  Finally, adequate PPE (personal protective equipment) is now available to protect workers from many arc flash incidents. 

If you have not yet implemented the requirements of NFPA 70E, please do so for the benefit of your employees and those who work in or visit your facility.  Good reading material is available starting with the NFPA and the IEEE.  Even if you plan to farm-out the implementation, it is recommended that some of your staff become knowledgeable on the standard.          

Tips on E-stop Circuits

1.) Mount the e-stop buttons where they can be easily accessed by the operator in an emergency.  Sometimes e-stops are inadventently bumped and activated by some operator action.  Don’t cover it with a guard!  Consider relocating it to another feasible location.  A button that is covered with a guard can’t be quickly activated in an emergency.

 2.) Activation of an e-stop should not create another hazard.  For example, leaving air-operated devices pressurized for an unexpectant mechanic.

 3.) Regularly test the e-stops in a dry-run mode.  Make sure power is disconnected to electrical devices and air dump valves work properly.

  4.) Make and enforce a policy concerning the modification of e-stop circuits.  Do not tolerate uncontrolled changes.