The History of Electrical Safety

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May is National Electrical Safety Month, so we are spotlighting electrical safety in our industry through the ages. Safety is important in any job, but in the electrical industry, safety is truly a life or death matter. Today, we have OSHA, the NEC, and many other protective guidelines in place to ensure safe working conditions for all electrical workers. As technology advances within the electrical field, new guidelines are created to maintain consistent worker safety and prevent accidents. With a long-storied history, electrical safety continues to evolve with the times.

The Founding of Electrical Safety

On September 4, 1882, Thomas Edison started the first commercial electrical power system. It produced 100 kilowatts of power, which lit 50 incandescent lamps, even though it generated enough wattage to light 1,200. Edison’s generating station produced direct current (DC) electricity, and just a few years later, Nicola Tesla and George Westinghouse created a system that produced alternating current (AC). They discovered that AC proved to be the superior system because it could transfer power over longer distances. Both of these industrial feats made great strides in the development of the modern world. However, soon after, an often-overlooked event created the need for electrical safety: the first electrical shock from an industrial generator.

In 1895, five different electrical installation codes were developed. These guidelines were put in place to keep workers safe and ensure uniform installation across the country. However, with five different codes, it was hard to keep the same standards from job to job. In 1897, a committee formed the previous year developed and published the National Electrical Code (NEC), one uniform electrical code that any electrician could use.

The National Fire Protection Associations (NFPA) became the sponsor of the NEC. The NFPA had two primary focuses: water and electricity. However, they soon found that fires were frequent in unsafe electrical conditions. Standards and practices involving the installation of sprinkler systems and electrical systems were necessary to maintain safety for workers and the public. In 1911, the NEC perfected the safety protocols and left the NFPA to update codes as the electrical field evolved.

Dalziel’s Discoveries

In 1956, after being asked to invent a device to electrocute barn flies, Charles Dalziel started to research electric shock. At the time, there was no existing data on the subject, so he performed tests on volunteers. These studies turned out to be a benchmark in electrical safety. Dalziel eventually went on to write “The Effects of Electric Shock on Man,” a very important book that further illuminated the importance of electrical safety.

In his investigations of electrical accidents, Dalziel found that many fatalities occurred from ground faults. Ground faults happen when inadvertent contact occurs between an energized conductor and ground or equipment frame. To help prevent ground faults, he invented GFCI outlets and breakers, a lifesaving and ground-breaking device that integrated a magnetic-sensing circuit with a newly developed semiconductor. The NEC mandated their use after seeing how effective they were in preventing electrical-related deaths.

Establishing a Burn Injury Scale

In 1969, Alice Stoll and Maria Chianta studied the effect of heat related to burn injury, inventing the Stoll Curve. The Stoll Curve determines the rating of the transfer of heat energy (calories) based on the time of transfer and the level of heat energy produced. In this study, women lined up and physically burned a number of young sailors on their forearms. They recorded the temperature and time. If blisters developed after 24 hours, the burns were recorded as second-degree burns. The results of this study are still used today to predict burn injuries.

Founding OSHA

In 1970, the United States Congress passed the Occupational Safety and Health Act. This resulted in the creation of the Occupational Safety and Health Administration (OSHA), which was formed to “assure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education, and assistance.”

Setting the Standard

In 1976, the NFPA formed a committee to develop newer electrical standards at the request of OSHA. First published in 1979, the NFPA 70E released the Standard for Electrical Safety Requirements for Employee Workplaces. Even today, the NFPA 70E is the core of electrical safety practices.

Arc Flashes

In 1982, Ralph H. Lee studied arc flashes and published a research paper titled “The Other Electrical Hazard: Electrical Arc Blast Burns.” Arcs are basically ionized gases caused when electricity travels through the air. This complex phenomenon is also known as an arc flash, arc blast, or electric arc. Lee’s paper focused on three main parts:

  1. Model an arc blast as an expanding sphere
  2. Determine whether the arc blast causes curable or incurable skin burns
  3. Recommend ways to protect workers

The understanding of arc flashes and safety suggestions that Lee provided have saved countless lives and helped many workers avoid injuries. However, it wasn’t until over a decade later, in 1995, that the NFPA 70E acknowledged the arc flash electrical hazard and started developing standards for dealing with it.

From 2000 to 2007, major strides were taken in response to arc flashes:

  • 2000 – NFPA 70E PPE developed tables to select FR fabric and PPE for protection against the thermal effects of arc flash
  • 2000 – Incident energy calculations were invented that allowed forecasting the prospective incident energy and became the foundation of today’s arc flash calculation techniques
  • 2002 – IEEE Guide for Performing Arc Flash Calculations is published, which defined methods to calculate the arcing short-circuit current, incident energy, and arc flash boundary
  • 2002 – The NEC requires arc flash warning labels for marking certain electrical equipment to warn of potential hazards
  • 2007 – The National Electrical Safety Code (NESC) requires that electric utility systems that fall under this standard must perform an arc flash assessment

Protective Equipment and Labeling Standards

Personal protection equipment (PPE), which is a very important part of personal safety, was addressed by the NFPA 70E in 2009, requiring additional labeling to make selections easier for qualified people working on or near live energized systems.

In 2015, OSHA updated its labeling standards for the NFPA 70E to further protect workers from the dangers of arc flashes. The new labeling requirements dictated that labels must contain nominal system voltage, arc flash boundary, and at least one of the following: available incident energy, corresponding working distance, minimum arc rating clothing, or site-specific level of PPE.

In 2018, the NFPA 70E edition emphasized the account for human error in a risk assessment to further understand electrical safety. The NFPA found that human error can diminish a safety program’s effectiveness, so the NFPA began proactively testing safety measures and protocols to minimize human error.

With new technology on the rise and new ways to harness power, updates and new safety requirements are inevitable in the electrical field. With such an ever-changing, yet adaptable, industry, it’s important to keep up with current regulations and maintain safety equipment to ensure your personal well-being. Whether you need protection from arc flashes or insulated tools to minimize the risk of electric shock, City Electric Supply has the safety equipment and tools you need to stay safe on the job.


City Electric Supply | History of Electrical Safety

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