Lockout/Tagout & Arc Flash Hazards
Proper lockout/tagout (LOTO) procedures on electrical equipment safeguard workers from hazardous electrical energy releases, which are typically electrical shock and arc flash hazards.
Since even low levels of electrical energy can kill, identifying electrical hazards and training in protective procedures is essential. A job hazard analysis (JHA) must be conducted before any work is started on electrical distribution systems or equipment.
The first and primary protective procedure should be LOTO, which de-energizes electrical circuits and equipment, generally reduces the hazard to zero. Even with LOTO, a worker still need to be aware that there may be other electrical hazards lurking, such as stored energy in capacitors. Completing a JHA for a task that can be completed with proper LOTO procedures requires the least amount of effort.
Work that requires the donning of Personal Protective Equipment (PPE) and exposing the worker to energized electrical circuits and equipment should be the last considered procedure. Proper PPE evaluation requires a much more complex JHA. Voltage levels must be known for appropriate shock protection. Various Arc flash hazard levels must be known for protection from potential arc flash energy.
Since arc flash analysis procedures only determine the PPE required to limit a worker’s electrical burns to curable second degree burn levels, wearing PPE and working on any live electrical circuit or equipment is way more dangerous than working on de-energized electrical circuits and equipment. Arc flash events also produce, 1) pressures which can break bones and/or cause concussions, 2) light flashes that can blind, 3) noise that can cause hearing damage, and 4) molten metal vapor that can be inhaled.
Without an understanding of the complete hazard, wearing PPE can give the worker a false sense of security. Arc flash events do not happen with any early warning, giving real meaning to “in an instant”.
You may see and/or hear a steam release, see something that is glowing red hot, or hear a warning to look out for falling objects. You cannot see or hear electricity. It does not give warnings.
Several current national and state codes and standards require labeling electrical service equipment with available fault current and labeling equipment with shock and arc flash hazard levels. The use of such labeling should be a worker’s and his employer’s very last resort.
Let’s get it right. Stay safe. No second chances. LOTO! LOTO! LOTO!