Posts tagged NFPA
New NFPA 70E standards for 2012 now require five specific pieces of electrical equipment to
have arc flash labels. They are switchboards, panel boards, industrial control panels, meter socket
enclosures and motor control centers. Aimed at improving electrical safety in commercial facilities,
the new standards focus on electrical equipment requiring maintenance while energized. New arc
flash labels must also include additional details. Each label must now indicate nominal system
voltage, arc flash boundary, and at least one of the following: available incident energy and the
corresponding working distance, minimum arc rating of clothing, required level of PPE or highest
hazard/risk category (HRC) for a piece of equipment.
The NFPA (National Fire Protection Association) provides five Hazard Risk Categories (HRC) to
define the level of an arc flash hazard. Each category is given as a single digit, designed to be easily
read by electrical workers from a safe distance, so that they may assess the relative danger of an arc
flash in a given situation and respond accordingly with the proper precautions and arc flash clothing.
Detailed HRC applications are described within the 2012 NFPA 70E standards, but in general, the
NFPA defines each HRC as follows. HRC 0 is generally used to describe non-contacting work
on various voltage ranges. HRC 1 describes work in an environment that may possibly produce
available incident energy of 4 cal/cm² to 7 cal/cm². HRC 2 describes work in an environment that
may possibly produce available incident energy of 8 cal/cm² to 24 cal/cm². HRC 3 describes work in
an environment that may possibly produce available incident energy of 25 cal/cm² to 39 cal/cm². And
HRC 4 describes work in an environment that may possibly produce available incident energy of 40
cal/cm² and greater.