Page 48 - IEC Insights May-Jun20

FEATURE

VDE THE TOOLS

THAT TRULY

WORK FOR YOU

Certified WHY ARC FLASHES HAPPEN

There are a variety of reasons why an Arc
Flash may occur, but most of them are
preventable. Most arc flashes occur when
maintenance workers are manipulating
Tools live equipment for testing or repair and
accidentally cause a fault. Improper tools,
improper electrical equipment, corrosion
of equipment, improper work techniques,
and lack of training are just some of the
reasons that can lead to a devastating arc
flash or arc blast.

RESULTS OF ARC
FLASH INCIDENTS
At such an extreme temperature, and
even at a significant distance, an Arc Flash
explosion can set fire to clothing and
severely burn human skin in fractions of
a second. Additionally, the extreme heat
can ignite nearby combustible materials,
liquefy or vaporize metal parts such as
copper, aluminum conductors, or steel
equipment parts. As the material rapidly
expands in volume, it changes state from
solid to vapor, resulting in an explosive
increase in air pressure and production of
A The resulting explosive pressures can push
severe sound waves.

ARC FLASH
workers off-balance, off ladders, or launch
them into walls or other equipment, and the
An Arc Flash is an electrical explosion due to a fault condition or short
circuit when either a phase to ground or phase to phase conductor is
resulting in hearing loss. Additionally, the
connected. Arc flashes cause electrical equipment to explode, resulting in
explosion can atomize metal materials into
an arc-plasma fireball. explosive sound blast can rupture eardrums,
the air, and solid metal debris and other
Temperatures may exceed 35,000° F (the surface of the sun is 9,000° F). loose objects, such as tools, can be turned
These high temperatures cause rapid heating of surrounding air and into deadly projectiles. Finally, the flash of
extreme pressures, resulting in an arc blast. The arc blast will likely the explosion can result in temporary or
vaporize all solid copper conductors which will expand up to 67,000 times permanent blindness. It is almost certain that
its original volume. The result of this violent event is usually the destruction the event will result in equipment damage,
of equipment, fire, and severe injury or death to anyone nearby. personnel injury, and possibly death.

46 Insights Magazine | May/June 2020 | www.ieci.org