What is an
Arc Flash?
An Arc Flash is a dangerous
condition associated with the explosive release of energy caused by an
electrical arc due to either a phase to ground or phase to phase fault
This fault can result from
many factors, including dropped tools, accidental contact with electrical
systems, build up of conductive dust, corrosion, and improper work procedures.
The explosive energy release
resulting from an arcing fault can consist of:
● Heat
● Pressure Wave
● Vaporized Metal (Plasma)
● Molten Metal Projectiles
Types of Injury from Arcing Faults
● Burns ● Hearing Loss
● Concussions ● Shrapnel Injuries
● Collapsed
Lungs ● Broken Bones
● Loss
of Limb ● Loss of Life
What is Required?
Workplace
safety is governed by OSHA. OSHA has adopted NFPA 70E as a consensus standard
for electrical safety. Per OSHA requirements the employer is required to
conduct a hazard risk assessment in accordance with OSHA 29CFR1910.132(d)(1)
before working on energized parts above 50 volts. If an arc-flash hazard is
present, or likely to be present, then the employer must select and require
employees to use protective apparel. Employers who conduct the hazard/risk
assessment, and select and require their employees to use protective clothing
and other PPE appropriate for the task, are deemed in compliance with the
Hazard Assessment and Equipment Selection OSHA Standard requirements.
By performing a proper arc flash analysis, you
can ensure that your workers have the proper protective safety equipment while
avoiding the expenses and lost productivity that will result from over or under
specification of PPE that can happen when using default tables of NFPA 70E when
an analysis is not performed.
What Does This Mean to You?
Per NFPA 70E-2000, Part II 2-1.3.3 Flash Hazard Analysis. “Flash hazard analysis shall be done before a
person approaches any exposed electrical conductor or circuit part that has not
been placed in an electrically safe work condition”.
This
Flash Hazard Analysis must be performed to determine the appropriate PPE
required for personnel working near any exposed electrical conductor or circuit
part. In order to determine the appropriate level of PPE required, the
available fault current at the energized electrical equipment being serviced
must be known.
A short circuit analysis must be performed to determine available fault
currents and arc flash hazards (calculated per IEEE 1584). By doing this
analysis, previous studies have shown that minor revisions in breaker settings
or fuse changes can lead to major reductions of arc flash hazards.
For More Arc Flash Information:
Phone: 615.714.7884
Fax: 615.826.5744