Tips for Conducting an Arc Flash Analysis

WHAT IS AN ARC FLASH HAZARD?

Arc Flash is a dangerous situation associated with the explosive release of energycaused by an electrical arc, due to a power system fault.

A fault can result from many things, including: improper work procedures or any other action that will short circuit energized parts; accidental contact with energized electrical systems, dropping apparatus or tools onto energized parts, and components, build up of conductive dust or corrosion, just to name a few.

In the event of an arc flash occurrence, the intense energy from the arc will vaporize the adjacent material which will produce a sudden air expansion/explosion (through the open side of the enclosure) and toward the employee, maintenance worker and/or a contractor.

DO YOU NEED AN ARC FLASH HAZARD ANALYSIS?

Short circuit faults can damage the facilities power distribution system and arc faults can be extremely dangerous, if not life threatening, to workers.

Ideally, the proper operation of an overcurrent-protective device, set off by an overcurrent condition or another anomaly, will at worst case interrupt the electrical supply and may disrupt processes in the facility or plant, but will not normally damage the system or pose a threat or safety risk to personnel or contractors.

A thorough analysis of the facilities electrical power distribution system and control systems, include:

Per NFPA 70E 2004, Article 130.3 requires that Arc Flash Hazard Analysis shall be performed to protect a person from the possibility of being injured by an arc flash or blast, identified hazards include arc flash blast, shock and electrocution.

The arc flash hazard analysis has two major components requiring calculations and are formally defined in NFPA 70E 2004 however, summarized below for the purposes of this explanation.

boundary “an approach limit at a distance from exposed live parts within which a person would receive a second degree burn if an electrical flash would occur”.

incident energy – measure of heat released in the arc flash in calories per square centimeter and further defines the appropriate PPE (Personal Protection Equipment) clothing required for personnel to wear, for arc flash protection, while working near any exposed to most energized electrical equipment.

In order to determine the appropriate level of PPE required, the available fault current at the energized electrical equipment being serviced must be calculated and the clearing time of the device opening the circuit to the fault reviewed.

Sample labels posted at each piece of equipment with the appropriate arc flash boundary, and PPE :

MAY WANT TO CONSIDER AN ARC FLASH STUDY, WHEN:

USING THE DEFAULT TABLES & INTERNAL STAFF VS. OUTSOURCING THE ANALYSIS?

The cost of the analysis, by a professional with experience in arc flash analysis is a small price to pay to avoid the expenses associated with an actual hazard due to incorrect calculations or over or under specification of PPE, that can happen when using default tables of NFPA 70E compared to when an analysis is not performed.

A realistic assessment and calculation can be obtained if performing a proper arc flash analysis, and you can enable your workers with the proper protective safety equipment and training.

Current Solutions, P.C. provides these studies and recommendations to help improve your overall power system safety. In today’s ever changing environment of electrical power distribution equipment and systems, safety and reliability are becoming the focal point of facilities.

FEATURES OF THE ARC FLASH STUDY:

Choose a licensed and registered professional electrical engineer, with power system studies and arc flash analysis experience, and who knows the National Fire Protection Association (NFPA) guidelines that are being enforced by Occupational Health and Safety Administration (OSHA).

 

The assessment should include:

CURRENT SOLUTIONS P.C.

Current Solutions, P.C. specializes in the analysis and design of power distribution systems and has provided these services for facilities across the US and Canada.