Electrical safety: Mitigating arc flash hazard strategies

Arc flash incidents pose a significant risk in electrical environments, leading to severe injuries and equipment damage and it’s important to know the critical measures for preventing them from happening.

By Herbert Post May 29, 2024
Courtesy: TradeSafe

 

Learning Objectives

  • Understand the causes of arc flash and the essential steps for hazard prevention.
  • Learn about NFPA 70E standards and how compliance contributes to workplace electrical safety.
  • Best practices in implementing effective safety measures to minimize arc flash risks such as risk assessment, personal protective equipment (PPE) usage and lockout/tagout (LOTO) procedures.

Arc flash insights

  • Arc flash incidents, occurring frequently in the US, cause fatalities and injuries, which highlights the urgent need for stringent safety measures and prevention strategies.
  • Adherence to NFPA 70E standards, coupled with risk assessments, proper PPE use and ongoing training, forms a robust framework for minimizing arc flash hazards.

Arc flash incidents are among the most challenging dangers in electrical environments, capable of causing devastating injuries and significant damage to equipment. These incidents are not rare and occur 5 to 10 times per day in the United States, resulting in more than 400 fatalities and 30,000 incidents annually. The energy released during these events can instantly vaporize metal and expose workers to extreme temperatures, blast pressures, and shrapnel, leading to severe burns, blindness, loss of hearing and fatalities in extreme cases​​.

There are several critical measures for preventing arc flash hazards, guided by National Fire Protection Association (NFPA) 70E standards, emphasizing the importance of risk assessments, appropriate personal protective equipment (PPE) and stringent isolation practices.

Understanding arc flash hazards

Arc flash incidents are severe electrical explosions that result from a fault in the electrical system, leading to the release of intense energy, light and heat. These explosive events occur when a substantial electrical discharge travels through the air, releasing intense heat, light, and pressure. The aftermath often includes severe burns, hearing loss, and even fatalities, underscoring the critical need for strict safety measures in any setting.

Figure 1: An arc flash occurring in an industrial setting.

Figure 1: An arc flash occurring in an industrial setting. Courtesy: TradeSafe

These incidents can occur due to various causes, including human error, equipment failure and environmental conditions.

  • Human error and carelessness: Many arc flash incidents result from mistakes such as failing to follow safety procedures, using incorrect or non-insulated tools, and bypassing lockout/tagout (LOTO) processes. Operator errors, distractions and overconfidence are significant contributors to these incidents​​.

  • Equipment and environmental factors: Faulty or improperly maintained electrical equipment, excessive dust, corrosion, and the presence of condensation or liquids near electrical equipment can also lead to arc flash incidents. Using substandard parts and improper installation of switches and circuit breakers also can create conditions that may lead to an arc flash incident​​.

Five steps for arc flash hazard prevention

To effectively mitigate the risks associated with arc flash incidents, it is crucial to follow a structured approach. Here are five important steps to prevent arc flash hazards:

  1. Conduct a thorough arc flash hazard analysis: Start by assessing the facility’s electrical systems and equipment to identify potential arc flash hazards. This involves gathering critical information such as equipment specifications, fault currents and protective device settings to accurately calculate arc flash incident energy levels and determine necessary PPE requirements​​.

  2. Develop, implement an integrated electrical safety program: Following the hazard analysis, create a comprehensive electrical safety program tailored to the facility’s needs. This program should cover safety measures and procedures that aim to minimize the risk of arc flash incidents, including clear safety policies, employee training and awareness programs and a robust equipment maintenance and testing regimen​​.

  3. Install adequate engineering controls: Enhance workplace safety by installing engineering controls that modify the electrical system to minimize the potential for arc flash events. Recommendations may include equipment upgrades and replacements, fault-current limiting devices and improved maintenance procedures to reduce hazards​​.

  4. Develop and communicate safety procedures: Establish specific safety procedures for responding to arc flash incidents. These should include emergency shutdown protocols, evacuation procedures, and first aid measures. Effective communication of these procedures is essential to ensure they are understood and followed by all personnel​​.

  5. Ongoing training, auditing and program improvement: To maintain the effectiveness of the arc flash mitigation program, it’s important to provide continuous education for employees, conduct regular audits to identify areas for improvement and update the program as needed. This ensures safe work practices are reinforced and compliance with the latest industry standards is achieved​​.

NFPA 70E standards overview

The NFPA 70E Standard is a critical document for ensuring electrical safety in the workplace, focusing on protecting workers from the dangers of shock, electrocution, arc flash and arc blast hazards. Compliance with NFPA 70E is essential for minimizing these risks and is enforced by OSHA as the recognized industry practice for electrical safety.

Figure 2: An infographic showing the steps for arc flash hazard prevention.

Figure 2: An infographic showing the steps for arc flash hazard prevention. Courtesy: TradeSafe

Key components of NFPA 70E relevant to arc flash prevention include:

  • Hazard identification and risk assessment: Emphasizes the importance of identifying electrical hazards and assessing risks to determine appropriate safety measures and controls.

  • Safety program implementation: Guides the development and implementation of comprehensive electrical safety programs, including safety policies, procedures and controls to minimize risk.

  • Use of personal protective equipment (PPE): Specifies requirements for selecting and using appropriate PPE to protect against electrical hazards, including arc flash.

  • Electrical safety training: Stresses the need for proper training for workers on safe electrical practices and the use of PPE.

  • LOTO procedures: Outlines procedures to ensure equipment is de-energized and cannot be started up again before the completion of maintenance or repair work.

  • Maintenance of electrical equipment: Highlights the importance of regular maintenance to ensure electrical equipment is functioning safely and efficiently.

Compliance with NFPA 70E standards significantly enhances workplace safety protocols by establishing a clear framework for electrical safety. These standards help organizations develop and maintain a culture of safety. Compliance ensures workers are properly trained, equipped with the necessary PPE and follow safe work practices to prevent electrical accidents, including arc flash incidents. This proactive approach to electrical safety not only protects workers but also reduces the potential for equipment damage and costly downtime, fostering a safer and more productive work environment.

Figure 3: A circuit breaker lock installed with a lockout/tagout (LOTO) lock.

Figure 3: A circuit breaker lock installed with a lockout/tagout (LOTO) lock. Courtesy: TradeSafe

Four best practices to minimize arc flash risks

When implementing effective safety measures to minimize arc flash risks, make sure these four best practices are always followed.

1. Conduct a risk assessment

Conducting a thorough arc flash risk assessment is the foundational step in identifying potential hazards within a facility. This process involves: gathering detailed information on the electrical distribution system, engineering analysis, and applying the findings of the assessment to improve safety measures and regularly updating the assessment to reflect changes in the facility or electrical system​​.

An example of minimizing risks through risk assessment is identifying areas with high incident energy levels and implementing engineering controls or administrative measures to reduce exposure to these hazards.

2. Detailed guidance on selecting, using PPE

Selecting the right PPE based on the results of the arc flash risk assessment is critical. PPE categories are defined based on the potential incident energy exposure, and selecting the correct level of protection can significantly reduce the risk of injury. It’s crucial to ensure PPE is correctly rated for the specific hazards workers might face​​.

An example of effective PPE use is the adoption of arc-rated clothing that matches the identified hazard level, along with insulated gloves and face protection, which can prevent severe burns and other injuries in the event of an arc flash.

3. Lockout/tagout (LOTO) procedures

Implementing strict LOTO procedures ensures that electrical equipment is properly de-energized before maintenance or repair work begins, reducing the risk of an arc flash incident. This involves:

  • Clear labeling and identification of energy sources.

  • Use of locks and tags to prevent unexpected energization.

  • Verification of de-energization before work starts.

An example of minimizing arc flash risks through LOTO is ensuring all sources of electrical energy are securely isolated before any repair work starts, preventing unexpected equipment startup.

4. Training and awareness

Continuous training and awareness programs for all employees, especially those working directly with or around electrical equipment, are essential. This includes:

  • Understanding the risks associated with arc flash.

  • Knowing how to correctly use PPE.

  • Being familiar with LOTO procedures and emergency response actions.

An example of how training and awareness minimize risks is conducting regular safety drills and training sessions that keep safety protocols top of mind, ensuring all employees know how to respond in case of an electrical emergency.

Table 1: A table that summarizes the key components of the NFPA 70E relevant to arc flash prevention.

Table 1: A table that summarizes the key components of the NFPA 70E relevant to arc flash prevention. Courtesy: TradeSafe

Future of arc flash safety

Arc flash safety is marked by technological advancements and fast-evolving trends in electrical safety. Innovations in smart sensor technology, predictive analytics and automation are set to change the way we approach and manage electrical safety. These technologies can identify hazards in real time, predict potential incidents before they happen and even automatically de-energize or shut off systems during an arc flash condition, which will significantly reduce the risks of injury.

Using Internet of Things (IoT) devices within electrical safety systems is expected to improve monitoring capabilities, enabling more precise risk assessments and more effective preventive measures. PPE advances such as better materials, comfort and durability are also expected to increase arc flash safety.

Another trend is the growing emphasis on safety culture where electrical safety, including arc flash mitigation, is rooted in every aspect of operations. This cultural shift, supported by continuous training and awareness programs, is crucial for sustaining a safe working environment.

The commitment to research and development in the field of electrical safety promises to mitigate the risks associated with arc flash incidents and promote a safer work environment, protecting lives and preventing injuries in the workplace.

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Author Bio: Herbert Post is VP of health and safety at TradeSafe. He has spent the last 13 years facilitating best practices and teaching updated regulations.