There is much confusion about compliance in regards to electrical hazards. Most people know that NFPA and OSHA are involved, but are unclear about what is required and when. The bottom line is facility managers want to know if NFPA 70E is required by OSHA.
The NEC 110.16 requires that any label state the existence of an arc flash hazard and the corrective action to take. The label must meet ANSI Z525 sign standard. The label should include the following:
The risk hazard category
Flash protection boundary
Incident energy at 18" expressed in cal/cm2
Voltage shock hazard
Limited shock approach boundary
Restricted shock approach boundary
Prohibited shock approach boundary
NFPA 70E gives two alternative methods of determining the arc flash category of the circuit in question. One method uses a series of task-based tables provided in NFPA 70E and quick calculations based on voltage, kva, etc. The downside of these tables is that they do not identify ways that you can reduce the hazards; they simply list the hazard risk category based on the type of equipment and the task being performed.
A more thorough method - and the one we use - is to have a complete arc flash analysis performed at your facility. This type of analysis involves a detailed field verification of your electrical distribution system, from your utility to the equipment on the facility floors. We then use software specifically designed to calculate the arc flash hazard level. Based on the results provided by the software, we write a set of detailed instructions for reducing the hazard levels. In addition, a full arc flash analysis will often turn up situations that eliminate the need to wear as much PPE. Often, we find the tables require a hazard risk category higher than is actually necessary once the hazard risk level has been calculated.