Arc flash events occur every single day in the United States, and some of them result in a fatality or severe burns for the victim.
Awareness of the dangers of arc flash events became prevalent in the ‘80s in the petrochemical industry, but as we well know, the awareness has diffused across most industrial and commercial systems, too.
The Occupational Safety and Health Administration has always required employers to provide workplaces free from recognized hazards. In response to the rise in arc flash events, OSHA has since enforced the regulations by referencing national consensus standards, such as NFPA 70E, Standard for Electrical Safety in the Workplace, to ensure employers protect employees from arc flashes.
The National Fire Protection Association’s (NFPA) 70E began to address the arc flash hazard in the 1995 Edition with the concept of “limits of approach” and the establishment of an “arc.” The 2000 Edition first introduced the (arc) flash protection boundary and the use of personal protective equipment (PPE). Today, NFPA 70E is used as the basis for electrical safety programs, and OSHA may levy citations and fines for inadequate programs.
To help protect the electrical worker, the National Electrical Code provides requirements for applying arc flash warning labels on electrical equipment. NFPA 70E also contains provisions for specific additional information to be incorporated into the label for use by the worker.
In addition to NFPA 70E and OSHA regulations, the Institute of Electrical and Electronics Engineers have published a standard used for the calculations in arc flash studies. Originally published in 2002, IEEE 1584—IEEE Guide for performing Arc-Flash Hazard Calculations is used globally to determine the incident energy of an arc flash. The arc flash boundary and arcing short circuit current calculations can also be performed using equations from this standard. Subsequent to its original 2002 publication, continuing research and additional testing will provide updates to the next edition of this standard that is currently under revision.
How do you stay safe from arc flash events, and are you fully aware of the danger signs?
The tips below incorporate several of the best practice guides set out by the stated institutions above. How many do you do on a regular basis, and how well are you protecting yourself?
(Editor's note: This article is not intended to be a comprehensive guide to arc flash safety. Instead, it is only meant to provide some practical tips and basic information. Refer to NFPA 70E and OSHA for more.)
What is arc flash?
“An arc flash is typically caused by accidental contact between energized electrical conductors, resulting in an arcing short circuit,” said Jim Phillips, P.E., founder of Brainfiller.com and ELECTRICAL CONTRACTOR Arc Flash columnist. “Any time a contractor or any person is working on or near exposed energized electrical systems and components, including interaction with the equipment, the risk of an arc flash exists.”
Have you established an electrically safe work condition?
“The best method to protect a person from an arc flash is to eliminate the hazard by placing the circuit into what is known as an 'electrically safe work condition,'” Phillips said. “This is more than just turning [the circuit] off. It requires steps such as reviewing up-to-date electrical drawings, diagrams and identification tags to determine all possible sources of electric supply to the equipment; opening the devices to isolate the system; using a documented lockout/tagout policy—and even then, it is not considered safe until the absence of voltage has been verified.”
In general, it’s best to follow these steps to create an electrically safe work condition:
- Identify all potential sources of electric power supply.
- Open the disconnect device for the respective sources.
- Apply lockout/tagout devices in accordance with a documented and established policy.
- Verify the absence of voltage of the respective conductors to ensure they’re de-energized.
- Ground the circuit if appropriate.
Of course, personal protective equipment must be worn to carry these steps out.
Have you analyzed the site correctly?
Although de-energized/electrically safe should always be the priority, if you must perform energized work, you must also complete an arc flash risk assessment. This defines the arc flash and the level of protective clothing required. This requires an incident energy calculation, which involves the following:
- Gathering all necessary data from both the system and installation
- Establishing the modes of operation
- Calculating the bolted and arcing fault currents
- Determining the protective device characteristic and arcing current duration
- Defining the working distances and calculating the incident energy
- Determining the arc flash boundary
Have you thought about training?
Arc flashes are indeed dangerous and potentially fatal, and yet there are methods to reduce the likelihood and risk associated with an arc flash. Therefore, you would be wise to seek out a training course that meets OSHA standards to learn about arc flash, OSHA and NFPA 70E Requirements. NFPA 70E requires retraining at intervals not to exceed three years. A comprehensive arc flash/NFPA 70E training course will help you and your employees meet new requirements.
“Many people think arc-rated PPE is all that is necessary to protect themselves from the arc flash hazard,” Phillips said. “Although properly selected PPE can offer protection to the worker, it is often cited as the last line of defense because, if you are relying on PPE to protect you, everything else has gone wrong. The best method for protection is to eliminate the risk by eliminating the hazard.”
Electrical Safety Standards continue to improve with each new revision. The 2018 edition of NFPA 70E, The Standard for Electrical Safety in the Workplace, includes detailed information related to risk assessment and the elimination of the hazard as the primary means of protection. By following the information found in NFPA 70E and the prescriptive measures for establishing an electrically safe work condition, workers performing electrical work will be protected. Through the evolution of safe work practices, awareness of the hazards and a greater emphasis toward working only on systems placed in an electrically safe work condition, incidents, injuries and fatalities have been significantly reduced and ultimately can be eliminated.
Raising awareness and familiarizing yourself is imperative to protect yourself and your colleagues and are important first steps.