Arc Flash Electrical Safety
What is an Arc Flash?
Arc Flash is the sudden, violent arcing fault generated by an electrical circuit to a fault condition, often caused by a short circuit. This short circuit can occur between a phase conductor (an energized or hot wire) and ground, neutral (a grounded conductor), or another phase conductor. The difference in magnitude and polarity of the wire’s voltage at any given time is what causes the arc. A familiar example of an Arc Flash is lightning.
An Arc Flash happens when these different potentials meet. Normally, we rely on protective devices like fuses or circuit breakers to limit the severity and duration of such events. However, in some cases, these devices may not act quickly enough to interrupt the current flow before an Arc Flash occurs.
In severe cases, conductors (usually copper) can transform from a solid to a liquid, and then to a gas almost instantaneously, causing an explosive expansion. This expansion can be up to 2,000 times the original volume. The resulting arc can produce temperatures hotter than the sun, ejecting solid metal particles and releasing a powerful blast of sound energy. While such events are rare, their potential severity necessitates that employers include Arc Flash warnings and training as part of an overall Electrical Safety Program.
What does an Arc Flash study entail?
Under the General Duty Clause, OSHA requires employers to provide “employment and a place of employment free of recognized hazards.” If an employee is injured in an electrical accident, OSHA will likely request the records of an Electrical Safety Program. This program should include Electrical Safety Training, protective gear for authorized employees, and an Arc Flash study that documents and labels the calculated electrical hazards from Shock and Arc Flash.
At ESC, we start by updating any existing documentation of your electrical systems. Most facilities have one-line drawings that show the electrical distribution coming into and throughout the facility. If not, we can create these drawings for you. Next, we model the facility using Arc Flash software, incorporating the voltages, wire sizes and lengths, and protective device information (circuit breakers and fuses). This creates a detailed model of the system.
Once the model is created, we print labels specific to each panel. Our general rule is that if a technician or maintenance person needs to open the panel while it's energized, the enclosure should have a label warning of the Shock Hazard and the magnitude of the Arc Flash potential at that location. Based on these hazards, authorized employees must wear protective gear and clothing (PPE) that exceeds the identified potential.
Contact ESC today to ensure your facility is compliant and your employees are safe. Our team is ready to assist you with comprehensive Arc Flash studies and Electrical Safety Programs. Stay safe and stay compliant with ESC.