Incident Prevention Magazine

Electrical power is a critical service that profoundly affects our daily lives. Without it, we would lose cellphone service, safety on city streets would be compromised because lights would not work, and the quality of life as we know it would diminish significantly. We would have to close schools and hospitals, and most jobs would be eliminated. Much of our food supply also would be critically impacted.

To continue living the life we are accustomed to – and have come to expect – we must have a reliable source of electricity, which starts with generation. Outside the generation station, power typically is stepped up to a higher voltage and usually ends up at a transmission system voltage (i.e., 115 to 550 kV). Transmission substations provide a means to transmit and protect the high-voltage transmission systems throughout the U.S. To distribute the power to homes and businesses, the transmission voltage is stepped down to lower voltages in distribution substations. Both transmission and distribution substations have breakers and fuses to provide system protection, along with many other parts and pieces that provide protection for equipment, personnel and the public, as well as reliability.

To ensure that power is always available, utilities must be diligent – engaging in regular inspections and National Electrical Safety Code (NESC) audits – in identifying conditions that may impact reliability and safety. The NESC has been around for approximately 100 years. Initially created as a guide to help electrical professionals understand safe design and work practices for generation, transmission and distribution systems, it is a culmination of many other standards, some of which will be referenced in this writing. Substations – or “supply stations,” as they are referred to in the NESC – are an integral part of our transmission and distribution infrastructure and have inherent hazards that must be considered.

Electric utility workers face complex, high-risk electrical hazards nearly every day. Information about shock hazards – which may come from impressed voltage, residual energy, induction, objectionable current flow in a grounding system or stored energy – has been taught to many of us for quite some time, as have the methods of assessing them.

On the other hand, arc flash hazard assessments are still relatively new to us. In the past, most of us knew that an arc flash could potentially occur during the course of performing our tasks, but the level of the flash and the PPE requirements – other than wearing 100 percent cotton – were not seriously considered in our day-to-day activities until approximately 15 to 20 years ago. To provide more concrete guidelines, OSHA published new regulations in April 2014, with more recent enforcement dates. Instead of making a best guess about PPE, the industry now has a reasonable approach to providing adequate PPE for utility employees who are tasked with performing open-air work. Once a utility completes the required arc flash analysis, develops a policy based on the analysis results and adequately conducts training for affected field personnel, the job of assessing risk and determining PPE levels can easily be incorporated into the daily job briefing. The goal is to make the assessment data easy to access and understand in order to provide effective protection for all workers.

Causes and Severity Levels of Arc Flash Events
An arc flash is the result of either a short circuit during which two energized parts of different potentials (phases) make contact, or a ground fault where an energized part and a grounded conductive part of a different potential make contact. An arc flash event may be caused by a failure of electrical apparatus, potentially due to lack of maintenance, or by worker error, perhaps due to an employee moving conductive parts near energized parts or leaving conductive tools in an energized work area. It’s important to note that differences in potential must always be effectively isolated by distance (air) or insulated barriers.

Utility workers are required to receive electrical safety training on a variety of topics, including grounding, switching and tagging, de-energizing, live-line work, pole-top rescue and job briefings. Unfortunately, there are some training topics – like how to properly secure loads on vehicles – that are not always given the attention they deserve. For instance, when I first passed my commercial driver’s license test 25 years ago, I had to undergo training on proper inspection of commercial vehicles, physical limitations, record keeping and proper driving techniques. Part of the training discussion was about securing the load on a commercial vehicle, but not much emphasis was placed on its importance. As you and I well know today, properly securing cargo is serious business, and a failure to follow the rules may result in injuries, death and jail time.

Electric utilities are among the most hazardous industries in which to work. This was recognized in the early days of electric power distribution when extremely high fatality rates occurred. Since those days, utilities have examined injuries and fatalities to learn how to prevent others. The examination process has included analyzing possible hazards, mitigating the identified hazards to a safe level of acceptable risk, creating policies and procedures, developing and providing protective equipment, and making the workplace as safe as it can be … or has it? Unless we make a conscious effort to verify that what has been developed and provided is used properly, safe work practices can only be assumed. By conducting field personnel work site observations on a consistent basis, we can substantiate and measure the effectiveness of organizational safety efforts, proving that the “safety first” culture is accurately represented.

Workplace safety is not an exact science. We can determine hazards, measure risks, provide protective equipment, implement policies and procedures – and then inject corrective actions when needed – but may still fall short of stellar performance.

Ground grids provide a fundamental safety feature in substations and should be tested periodically. Unfortunately, some are approaching 100 years old and haven’t been tested in many years.

An integral part of any electric utility infrastructure, substations that are properly designed and maintained by qualified and trained workers are safe and reliable. If a failure occurs, however, it can be catastrophic and even disastrous.

A simple and effective system for ensuring proper fall protection.

The development of an effective fall protection program has long been a tough issue to deal with. Many of the hazards that utility workers face often seem impossible to provide adequate protection for without introducing some other unsafe condition. And once systems are developed, getting workers to use them is another problem.