Dangers of Arc Flash

What is an Arc Flash?

Arc Flash is an electrical short circuit where a high level of current and corresponding energy pass through the air surrounding electrical equipment. Arc Flash causes the equipment to explode with tremendous force resulting in a lethal fireball with temperatures exceeding 35,000 degrees F. (Note: the surface of the sun is approximately 9,000 degrees F.) The explosive arc blast will generate high temperatures and extreme blast forces surrounding the equipment.Within the arc blast is a cloud of vaporized metal expanding to several times the original volume and traveling at speeds of over 700 mph. There is no escape from the direct blast of an arc flash. The blast duration can be less than one second and can produce a pressure blast equal to the force of several sticks of dynamite. The arc flash may be initiated without any warning, from dust or other conductive materials that commonly accumulate on bussing, insulators and devices, or due to protective device failure.Resetting a breaker or simply opening a panel may trigger an arc flash explosion.

Is an Arc Flash Study required for Code and Labor compliance?

The answer is YES! Several recent changes in the Electrical Code, NFPA 70 and OSHA regulations state that “an arc flash hazard analysis shall determine the arc flash boundary, the incident energy at the working distance, and the personal protective equipment that people within the arc flash boundary shall use.”The NEC requires that arc flash warning labels be applied to electrical equipment to warn of potential arc flash hazards.If an Arc Flash Hazard Analysis has not been performed for your facility, then you are missing this essential protection plus the required labels and protection for your employees and other personnel.

This is a Labor Compliance issue.

Additionally, for hospitals, fully compliant Arc Flash labeling is a JACHO requirement. NFPA 70E 2012 - 130.3 (A): An arc flash hazard analysis shall determine the arc flash boundary, the incident energy at the working distance, and the personal protective equipment that people within the arc flash boundary shall use.”

This exposure of the employee to the energized parts of electrical equipment places a requirement on the employer to provide Personal Protective Equipment (PPE). The NFPA 70E further outlines what level of PPE is required to be provided by the employer, which is mandated by the level of arc flash incident energy that exists within each electrical panel or equipment, as determined by an Arc Flash Hazard Analysis.

Required Personal Protective Equipment “PPE”:

Personal Protective Equipment (PPE) is used to limit the injury incurred during a fault to a level no greater than the exposure of bare skin to an open flame for approximately 1 second, (approximately 1.2 cal/cm2) which equates to a curable second degree burn. If you have not had an Arc Flash Hazard Analysis performed for your facility, then personnel must wear this bulkygear when working around ANY and ALL electrical equipment within your facility, NO EXCEPTIONS.Additionally, some major equipment may have an Arc Flash level so extreme that even PPE cannot protect an employee, in which case the equipment must be de-energized before any work or adjustment may be performed. You will not know if this extreme hazard exists without a professional Arc Flash Hazard Analysis and mandated warning labels.

How to Reduce Arc Flash Incidents:

There are three ways that Arc Flash Incident may be decreased. First, the available short circuit current from the utility company may be reduced. Second, the impedance of the power distribution system could be increased. Third, the trip settings on your protective devices may be reduced to regulate the let-through energy, within limits, to maintain essential protective coordination. The benefit of a comprehensive Arc Flash Hazard Analysis is to evaluate and recommend ways of decreasing the Arc Flash Incident to reduce the level of Personal Protective Equipment required.

Why Should Miller-Pezzoni and Associates, Inc. Perform your Arc Flash Hazard Analysis?

It is imperative that an Arc Flash Hazard Analysis be accurate and completed professionally.An Arc Flash Hazard Analysis is a vital element of your employee safety program. This analysis can save lives.Therefore it is crucial that you obtain a Professional Arc Flash Hazard Analysis prepared by a team of highly experienced registered professional engineers and power system experts.

Working closely with your facilities’ personnel and your utility company, we will procure detailed data on your electrical distribution system, including impedances and other relevant data from the utility company. Information including sizes and lengths of feeder cables, cable types, raceway materials and settings of your protective devices will be field verified. Based upon this information, we will prepare a detailed, accurate and professional Arc Flash Analysis for your facility, signed and sealed by a Registered Professional Electrical Engineer.

As an added benefit, we will analyze your protective device settings and provide a complete coordination study for the portion of your system included in our analysis. This data may be further utilizedto recommendadjustment of protective device settings to maintain proper system coordination.

In other words, a proper coordination study will help ensure if a current overload or ground fault should occur, the protective devices will only shut down the areas immediately adjacent to the fault. The outage will not cascade throughout your facility, which can result in a facility-wide outage with disastrous consequences. This is particularly vital in Acute Medical Facilities and certain manufacturing processes.

We will print all legally required labels and assist your staff with the installation.In addition, we are available to provide an in-house technical seminar with your staff on the hazards of Arc Flash.

Protect your Employees and Ensure your Safety Compliance.