Page 32 - Energize June 2021

TECHNICAL

Protecting operators from the risks

of electrical arc flashes

Information from Charnaud

Arc flash incidents release massive amounts of heat and power in only a few seconds. If you’re caught in
an accident with that much energy, it’s unlikely that you’ll walk away without an injury.

The dangers of arc flashes What you need to know about arc flash
Arc flashes occur when electrical current Arc flash is a term used to describe low impedance connections in an electrical system. The
flows outside its intended path, through low impedance allows movement of unwanted electrical discharge through the air from one
an air gap, to another conductor, or a phase to another. The resulting change in temperature and pressure can cause an explosion,
type of electrical explosion or discharge which is called an arc flash.
that results from a connection through The flash can lead to fires, shrapnel, and serious, even fatal injuries. Aside from taking
air to ground or another voltage phase in steps to prevent the creation of an environment in which arc flashes can occur, you should
an electrical system. There are a number also ensure that your team wears appropriate protective gear to keep them safe should an arc
of things that can cause an arc flash and flash occur.
anyone who works with electricity is at risk
of the injuries it can cause. Personal protective equipment (PPE) to protect against arc flash
While the prevention of an arc flash is always the best option, it pays to prepared for all
The risks involved with arc flash eventualities, including equipping your electrical crews with the PPE they require to protect
Arc flashes can cause injuries such as them, should an arc flash occur. Professional PPE includes shirts, boots, gloves and switching
third degree burns and can even result suits and hoods. This equipment is made to protect against the thermal effects from arc flash,
in blindness, hearing loss, nerve damage flash fire and flames. n
and cardiac arrest. It is not unheard of for
people standing up to three metres away Contact Charnaud, Tel 011 794 6040, sales@charnaud.co.za
from the arc flash to suffer serious burns.
Arc flashes can spray droplets of molten
steel at high speed and the resulting
shrapnel can be as hot as 800°C. Blast
pressure has been known to throw workers
across rooms and knock them off ladders.
In short, arc flashes are no joke, and
workers must be protected against them.

How common is an arc flash?
Arc flash is hardly an uncommon
phenomenon. In the United States, it is
estimated that it occurs between five and
ten times per day, resulting in over 400
fatalities and 30 000 incidents per year.
Statistics in the UK and South Africa are
somewhat less certain. Considering the
sheer scale of electrical installations across
an industrialised nation such as the United
States, five to ten events per day may not
seem like that many – indeed, in the grand
scheme of things, major arc flash accidents
are indeed relatively rare. However, they
can still cause considerable damage, the
worst-case scenario being the loss of life,
and could happen at any time.

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