ARC FLASH REQUIREMENTS

	WARNING
Arc Flash and Shock Hazard
Appropriate PPE Required

S

afety concerns within industry are causing major changes in safe electrical work practices. NFPA 70E-2004 has caused great changes with its references to arc flash hazards. These hazards are caused from arcing current flowing through the plasma created during an arcing fault. The tremendous heat and energy introduced by these faults can cause serious injury or death if proper protection is not used. A simple slip of a worker’s hand could cause arcing temperatures as hot as the surface of the sun and an explosion releasing shrapnel from the point of fault endangering not only themselves but also other workers in the area. It is imperative that equipment is put in a “safe working condition” (NFPA 70E) and the use of lockout/tagout procedures (OSHA 1910.333b) is used to keep workers safe. Verifying the absence of potential is required in both NFPA 70E and OSHA 1910.333b. If it seems essential that work be done on energized equipment, OSHA 29 CFR Subpart S.1910.333 seriously limits this kind of work.

“Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is feasible due to equipment design or operational limitations.”

Financial reasons cannot be considered an adequate reason to work on energized electrical equipment.

The process of deenergizing the electrical equipment and putting it into a safe condition introduces employees to risk. Since testing for the absence of potential is considered working on live parts according to OSHA 1910.333(b) and NFPA 70E-2004, personal protective equipment is required. The problem is determining the amount of protection required for a specific task. NFPA 70E-2000 uses generic tables that can give a basis of protection for the worker, but it does not give an arcing distance at which other workers may still be in danger.

A flash hazard analysis will determine the amount of arcing fault energy that your equipment has and the boundary at which injury can be sustained by working on this equipment. This boundary can be calculated using NFPA standards and IEEE standards. Also, NFPA 70E tables can either undercut the amount of protection needed or cause a worker to wear more PPE than needed. By using techniques developed by NFPA 70E-2004 and IEEE 1584a-2004, PRIT Service can perform a flash hazard analysis and help your facility comply with the following standards:

· NEC 110.16, Flash Protection Field Marking

· NFPA 70E-2004, Standard for Electrical Safety In the Workplace

· ANSI Z535.4-1998, Product Safety Signs and Labels

Our engineers can facilitate any question you may have regarding your power system. Call us to today to learn how PRIT Service can benefit you and your facility.