“It all starts with Electrical Safety — the reason we’re all here. The NFPA 70E defines Electrical Safety as “Identifying hazards associated with the use of electrical energy and taking precautions to reduce the risk associated with those hazards.” Okay, but what’s a hazard? And what makes a risk?
A Hazard is defined as “a source of possible injury or damage to health,” like electrical shock or arc flash arc blast. By Risk we mean “a combination of the likelihood of occurrence of injury or damage to health and the severity of injury or damage to health that results from a hazard.” Examples of risk are “Burns from exposure to heat generated from an arc flash event” or “Fatalities as a result of contacting energized equipment and receiving an Electrical Shock”. Because electrical hazards put us at risk in the workplace, we need to protect ourselves using the Control Methods you’ll find in the Hierarchy of Risk Control.
The Hierarchy of Risk Control is a priority-based approach to preventive and protective measures taken to reduce or eliminate the risk of electrical injury or fatality.
There are 6 different control methods in the hierarchy. In order of priority, they are Elimination, Substitution, Engineering Controls, Awareness, Administrative Controls, and Personal Protective Equipment, or PPE. EPSCO groups the top three and the bottom three into two distinct categories – Inherent Controls for the top, and Dependent Controls on the bottom. Inherent Controls are built right into the equipment. Dependent Controls rely on worker participation to be effective. Before we know which control method to implement, we must first understand the risks associated with the given task or equipment.
That brings us to the idea of Risk Assessment. It allows us to understand all the risks associated with specific hazards in the workplace. Risk Assessment is “An overall process that identifies hazards, estimates the likelihood of occurrence of injury or damage to health, estimates the potential severity of injury or damage to health, and determines if protective measures are required.” Arc Flash studies have been a key source of information for assessing hazard severity within facilities. There are a lot of terms and concepts that come along with understanding Arc Flash. Let’s get to know them now…
Incident Energy Calculation helps workers understand the potential severity of injury or damage to health. It’s typically expressed in Calories per centimeter squared. Some people say “cals” for short. Incident Energy Calculation allows us to effectively select the proper protective measures and suit up in the correct PPE for the task.
Incident Energy itself is simply a calculation of the amount of heat caused by an arc flash. Technically speaking, it’s “The amount of thermal energy impressed on a surface, a certain distance from the source, generated during an electrical arc event…” Keep in mind that the arc flash study alone won’t estimate the likelihood of an event occurring in each specific case. What is does do is specify working boundaries. There are three you’ll need to know — the Arc Flash Boundary, the Limited Approach Boundary, and the Restricted Approach Boundary. “
