Peter Walsh, PE
The 2012 edition of NFPA 70E has expanded the requirements for labeling arc flash hazards of electrical equipment. Most electrical equipment should now be labeled with the degree of arc flash hazard. When an electrical contractor performs service on equipment he relies upon the label, if any, for choosing the correct personal protection equipment.
Paragraph 130.5(C) now requires a field marked label containing all the below information.
1. At least one of the following:
2) Nominal system voltage
- Available incident energy and corresponding working distance
- Minimum arc rating of clothing
- Required level of PPE
- Highest Hazard/Risk Category (HRC) for the equipment
3) Arc flash boundary
There is an exception. If the labels were placed on the equipment prior to September 30, 2011 and they have the information required in the previous edition, they are sufficient.
This change enables an OSHA inspector to determine at a glance whether arc flash hazard analysis was done as required by OSHA regulations. The inspector can also readily see if the label matches up with the electrician's level of PPE. The level of safety compliance is more obvious to everyone, including the electricians.
Sometimes the hazard level is too great and people should not be exposed to it. Sometimes the PPE is too cumbersome for extended work. What can be done?
Manufacturers such as Eaton have developed an arc flash reduction maintenance system. They state that when circuits using the maintenance switch mode have an arc fault, this technology is faster. This results in a lower hazard compared to other technologies such as Zone-Selective-Interlocking and typical instantaneous adjustments on circuit breakers.
Photo courtesy of Eaton Corporation