The arc flash hazard, a major cause of serious electrical accidents, should not be confused with the electric shock hazard. Arc flash involves an internal fault in the installation, and more specifically, a short circuit within electrical equipment, as well as human exposure to the resulting explosion. The consequences of such an explosion primarily include the release of a large amount of thermal energy, intense light and sound emissions, and the generation of a pressure wave. If a person is present during such an event, they may suffer burns, loss of vision and hearing, or injuries due to the force of a fall. On the other hand, electric shock occurs when the human body comes into direct or indirect contact with a conductive part at a different electric potential, posing risks of muscular, respiratory, and cardiac damage.

Statistical data show that workplace accidents caused by arc flashes are the most frequent ones, largely due to a lack of awareness and training among workers regarding arc flash safety and protection.

In recent years, more and more governmental bodies have been enforcing protective measures through legislation or guidelines. These measures include

  • clear labeling of electrical panels,
  • defining safety distances,
  • providing appropriate personal protective equipment (PPE),
  • reducing the anticipated incident energy in case of an arc flash,
  • establishing safe work procedures, and
  • training personnel.

All these measures aim to minimize risk and can be comprehensively defined through a specialized arc flash risk assessment.

PROTASIS offers such specialized arc flash risk assessments in both the Greek and international markets, in compliance with the international standards NFPA 70E and IEEE 1584, ensuring a realistic risk evaluation. Simplistic, empirical approaches often lead to unreliable results and should be avoided.

The arc flash risk assessment methodology consists of several sequential tasks. First, an on-site inspection is conducted at the electrical installations under review, and the required input data are collected. Once organized and categorized, the network model is developed using appropriate simulation software. Following that, short-circuit and protection coordination studies are performed. Finally, key parameters are calculated for the arc flash risk assessment (arcing current, expected incident energy, safety boundaries, hazard category) for each work location, and suitable risk reduction measures are proposed.

It’s also important to note that these studies should be updated regularly, usually at intervals of less than five years, and revised whenever a significant change occurs in the electrical network that could increase the risk at the associated work points.

This article was initially published in INDUSTRY magazine, in April 2023.