- Safety Corner | January 15, 2020
Recognizing Hazards - Continuing the Journey
Some may argue that an important attribute of a qualified individual in the electrical industry is the ability to recognize electrical hazards. An electrical hazard is a dangerous condition that could result in electric shock, arc flash burn, thermal burn, or arc blast injury. The first step to success is to understand what electrical hazards are and then to realize that not all electrical equipment or applications are the same. The journey to recognizing electrical hazards is not necessarily straight forward but there are some basic concepts that once understood can make a difference in success.
THE ELECTRICAL HAZARD
The challenge with electricity is that we can’t see it. An object that is energized looks just like an object that is not energized. That is as long as that object isn’t using the electricity to move something, light somethingor display something. The electrical worker has three basic things we worry about when working with electricity,
- Electric shock
- Arc flash
- Arc blast
Although these seem very straight forward, reality is that it’s the details we comfortably generalize that the electrical worker, during a midnight call to fix a problem, can’t overlook. That individual doesn’t have the luxury of talking in generalities. He or she in that moment is where the rubber meets the road.
The challenge with avoiding shock is the ability to know what is and what is not energized or also what may or may not become energized because of you or someone else’s action. Shock occurs when a person comes in contact with something that is energized. The process of determining what could be energized or what can become energized can be challenging. An important part of this process is the understanding of the equipment that is being worked on as well as an understanding of the system within which it is installed.
An in-depth understanding of the equipment in which work is being conducted is very important. Just because you or your employee have installed and worked on a panelboard does not constitute the ability to recognize the hazards of all panelboards, switchboards, motor control centers and other types of equipment.
Even if you or your employee are knowledgeable about the electrical equipment within which electrical work will be conducted, the system that supplies power to that equipment is also an important aspect of the work that could make you or your employee not qualified for the job. A panelboard in a data center, residential home, steel mill, or petrochemical facility can present the electrical worker with the same equipment but much
different challenges and hazards.
The magnitude of the arc flash or arc blast event can be driven by the equipment that is supplying power. The upstream overcurrent protective device performance plays a critical factor in how much energy an electrical worker may face when justified energized work is being conducted. Depending upon the overcurrent protection selected, the condition of maintenance may play a critical factor in clearing time and so a critical factor in the amount of energy delivered downstream. The electrical worker must understand the key aspects of clearing time and fault current as well as condition of maintenance to reduce the risk involved with the job at hand. Dressing correctly is important for safety and determining the level of PPE to be worn is critical and dependent upon understanding the power system in depth including power flow and available fault currents and clearing times.