Arc Flash FAQs
What is Arc Flash?
Arc Flash is the sudden release of energy caused by an electric arc.
Are Arc Flash Studies required for office buildings? Aren’t those only applicable to Industrial Applications?
Per NFPA-70E-130.5(D) electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling units and are likely to require examination, adjustment, servicing, or maintenance while energized shall be field-marked with a label identifying:
What is the NFPA-70E, and who enforces it?
The NFPA -70E: Standard for Electrical Safety in the Workplace, is a comprehensive standard authored by the Committee on Electrical Safety Requirements for Employee Workplaces, an electrical standards committee formally appointed by the National Fire Protection Association (NFPA) on January 7, 1976, to assist the Occupational Safety and Health Administration (OSHA) in preparing electrical safety standards that would serve OSHA’s needs, which would be promulgated through the provisions of Section 6(b) of the Occupational Safety and Health Act. – NFPA-70E-100
While not formally adopted by OSHA, the electrical installation requirements and the electrical safety-related work practices in OSHA’s general industry standards in Subpart S – Electrical Work, are based on previous editions of 70E. Additionally, a national consensus standard, such as NFPA-70E, can sometimes be relevant to a general duty clause citation in the sense that the consensus standard may be used as evidence of hazard recognition and the availability of feasible means of abatement. – OSHA Interpretation Letter – October 18, 2006
What is an Arc Flash Hazard?
A dangerous condition associated with the possible release of energy caused by an electric arc. – NFPA 70E-100
What is an Arc Flash Boundary?
When an arc flash hazard exists, the Arc Flash Boundary is the approach limit at a distance from a prospective arc source within which a person could receive a second degree burn if an electrical arc flash were to occur. – NFPA 70E-100
What is an Electrical Hazard?
A dangerous condition such that contact of equipment failure can result in electric shock, arc flash burn, thermal burn, or blast. – NFPA-70E-100
What is Incident Energy?
The amount of thermal energy impressed on a surface, a certain distance from the source, generated during an electrical arc event. Incident energy is typically expressed in calories per square centimeter (cal/cm2). – NFPA-70E-100
What is Incident Energy Analysis?
A component of an arc flash risk assessment used to predict the incident energy of an arc flash for a specified set of conditions. – NFPA-70E-100
Who is a “Qualified Person”?
One who has demonstrated skills and knowledge related to the construction and operation of electrical equipment and installations and has received safety training to identify and avoid the hazards involved. – NFPA-70E-100
What is a Risk Assessment?
An overall process that identifies hazards, estimates the potential severity of injury or damage to health, estimates the likelihood of occurrence of injury or damage to health, and determines if protective measures are required. – NFPA-70E-100
What does a Risk Assessment entail?
A risk assessment procedure shall identify the process to be used by the employee before work is started to 1) Identify hazards, 2) Assess risks, 3) Implement risk control according to a hierarchy of methods. – NFPA-70E -110.1(G)
What is a Shock Hazard?
A dangerous condition associated with the possible release of energy caused by contact or approach to energized electrical conductors or circuit parts. – NFPA-70E-100
What constitutes “working on energized equipment”?
Intentionally coming in contact with energized electrical conductors or circuit parts with the hands, feet, or other body parts, with tools, probes, or with test equipment, regardless of the personal protective equipment (PPE) a person is wearing. There are two categories of “working on”: Diagnostic (testing) is taking readings or measurements of electrical equipment with approved test equipment that does not require making any physical change to the equipment; Repair is any physical alteration of electrical equipment (such as making or tightening connections, removing or replacing components, etc.) – NFPA-70E-100
Who is responsible for application of Safety-Related Work Practices?
NFPA-70E states “the employer shall provide safety-related work practices and shall train the employee, who shall then implement them.” – NFPA-70E-105.3
What are the requirements for Electrical Safety Training?
NFPA-70E-110.2 outlines the various requirements for Training. Among these are:
What are the requirements for an Arc Flash Risk Assessment?
NFPA-70E-130.5 states an Arc Flash Risk Assessment shall:
Determine if an arc flash hazard exists, and if such a hazard exists, shall determine:
NFPA-70E-130.5(A) states the results of the arc flash risk assessment shall be documented.
NFPA-70E-130.5(B) provides the requirements for establishing the Arc Flash Boundary as either the distance at which the incident energy equals 5 J/m2 (1.2 cal/cm2), or as determined by the Table 130.7(C)(15)(A)(b) or Table 130.7(C)(15)(B), where applicable.
NFPA-70E-130.5(C) states the selection of PPE is to be determined by either 1) Incident Energy Analysis Method based on the working distance from prospective arc source, or by 2) the Arc Flash PPE Category Method utilizing the Table Method prescribed in 130.7(C)(15) & 130.7(C)(16).
NFPA-70E-130.5(D) states electrical equipment such as switchboards, panelboard, industrial control panels, meter socket enclosures, and motor control centers located in other than dwelling units and which are likely to require examination, adjustment, servicing, or maintenance while energized shall be field marked with a label containing:
Who is responsible for Arc Flash Labeling?
NFPA-70E-130.3(D) states the owner of the electrical equipment shall be responsible for the documentation, installation, and maintenance of the field-marked label.
When are Arc Flash Labels required to be updated?
NFPA-70E(130.5(D) states “where the review of the arc flash hazard risk assessment identifies a change that renders the label inaccurate, the label shall be updated.”
Which Arc Flash Evaluation Method is right for me?
While NFPA-70E permits the used of the Table method for determining the Arc Flash Boundary, this method does not take into all of the characteristics unique to a given electrical installation that may have an effect on the actual incident energy at a given point in the system. As a result, a true calculation-based analysis provides greater accuracy in establishing the Arc Flash Boundary based on actual conditions, often resulting in lower PPE requirements when compared to the Table method.
Why is accuracy important in performing Arc Flash Evaluations?
The primary purpose of an Arch Flash Evaluation is to educate the employee or technician who is to perform work on the equipment, of the electrical hazards present. Using this information, that person then selects the appropriate PPE for the task. However, there is also an inherent risk associated with use of the PPE when working on energized equipment. As the protective rating of PPE increases, the flexibility and dexterity of the person wearing the equipment decreases, potentially increasing the overall risk of an arc flash incident occurring during the performance of work. Therefore, it is important to select the right PPE for the job.
A point calculation-based study takes into consideration the unique properties inherent to a system, resulting in greater accuracy in the determination of the incident energy and required arc flash boundary throughout the system. This means employees and technicians are armed with more accurate information enabling them to select the right PPE for the task, while maintaining optimal dexterity and flexibility while using the PPE. As a result, the overall safety measures are improved.
Arc Flash is the sudden release of energy caused by an electric arc.
Are Arc Flash Studies required for office buildings? Aren’t those only applicable to Industrial Applications?
Per NFPA-70E-130.5(D) electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling units and are likely to require examination, adjustment, servicing, or maintenance while energized shall be field-marked with a label identifying:
- Nominal System Voltage
- Arc Flash Boundary
- At least one of the following:
- Available incident energy and the corresponding working distance, or the PPE category as determined by Table 130.7(C)
- Minimum arc rating of clothing
- Site-specific PPE
What is the NFPA-70E, and who enforces it?
The NFPA -70E: Standard for Electrical Safety in the Workplace, is a comprehensive standard authored by the Committee on Electrical Safety Requirements for Employee Workplaces, an electrical standards committee formally appointed by the National Fire Protection Association (NFPA) on January 7, 1976, to assist the Occupational Safety and Health Administration (OSHA) in preparing electrical safety standards that would serve OSHA’s needs, which would be promulgated through the provisions of Section 6(b) of the Occupational Safety and Health Act. – NFPA-70E-100
While not formally adopted by OSHA, the electrical installation requirements and the electrical safety-related work practices in OSHA’s general industry standards in Subpart S – Electrical Work, are based on previous editions of 70E. Additionally, a national consensus standard, such as NFPA-70E, can sometimes be relevant to a general duty clause citation in the sense that the consensus standard may be used as evidence of hazard recognition and the availability of feasible means of abatement. – OSHA Interpretation Letter – October 18, 2006
What is an Arc Flash Hazard?
A dangerous condition associated with the possible release of energy caused by an electric arc. – NFPA 70E-100
What is an Arc Flash Boundary?
When an arc flash hazard exists, the Arc Flash Boundary is the approach limit at a distance from a prospective arc source within which a person could receive a second degree burn if an electrical arc flash were to occur. – NFPA 70E-100
What is an Electrical Hazard?
A dangerous condition such that contact of equipment failure can result in electric shock, arc flash burn, thermal burn, or blast. – NFPA-70E-100
What is Incident Energy?
The amount of thermal energy impressed on a surface, a certain distance from the source, generated during an electrical arc event. Incident energy is typically expressed in calories per square centimeter (cal/cm2). – NFPA-70E-100
What is Incident Energy Analysis?
A component of an arc flash risk assessment used to predict the incident energy of an arc flash for a specified set of conditions. – NFPA-70E-100
Who is a “Qualified Person”?
One who has demonstrated skills and knowledge related to the construction and operation of electrical equipment and installations and has received safety training to identify and avoid the hazards involved. – NFPA-70E-100
What is a Risk Assessment?
An overall process that identifies hazards, estimates the potential severity of injury or damage to health, estimates the likelihood of occurrence of injury or damage to health, and determines if protective measures are required. – NFPA-70E-100
What does a Risk Assessment entail?
A risk assessment procedure shall identify the process to be used by the employee before work is started to 1) Identify hazards, 2) Assess risks, 3) Implement risk control according to a hierarchy of methods. – NFPA-70E -110.1(G)
What is a Shock Hazard?
A dangerous condition associated with the possible release of energy caused by contact or approach to energized electrical conductors or circuit parts. – NFPA-70E-100
What constitutes “working on energized equipment”?
Intentionally coming in contact with energized electrical conductors or circuit parts with the hands, feet, or other body parts, with tools, probes, or with test equipment, regardless of the personal protective equipment (PPE) a person is wearing. There are two categories of “working on”: Diagnostic (testing) is taking readings or measurements of electrical equipment with approved test equipment that does not require making any physical change to the equipment; Repair is any physical alteration of electrical equipment (such as making or tightening connections, removing or replacing components, etc.) – NFPA-70E-100
Who is responsible for application of Safety-Related Work Practices?
NFPA-70E states “the employer shall provide safety-related work practices and shall train the employee, who shall then implement them.” – NFPA-70E-105.3
What are the requirements for Electrical Safety Training?
NFPA-70E-110.2 outlines the various requirements for Training. Among these are:
- Type of Training – must be classroom or on-the-job training, or a combination of the two. The type and extent to be determined by the risk to the employee.
- Emergency Response Training – Contact Release, First Aid, and Resuscitation
- Training Verification – document completion of required training
- Retraining
What are the requirements for an Arc Flash Risk Assessment?
NFPA-70E-130.5 states an Arc Flash Risk Assessment shall:
Determine if an arc flash hazard exists, and if such a hazard exists, shall determine:
- Appropriate safety-related work practices
- The arc flash boundary
- The PPE to be used within the arc flash boundary
- Be updated when major modification or renovation takes place, and shall be reviewed periodically, at intervals not to exceed 5 years.
- Take into consideration the design of over-current protective device and its opening time, including its condition of maintenance.
NFPA-70E-130.5(A) states the results of the arc flash risk assessment shall be documented.
NFPA-70E-130.5(B) provides the requirements for establishing the Arc Flash Boundary as either the distance at which the incident energy equals 5 J/m2 (1.2 cal/cm2), or as determined by the Table 130.7(C)(15)(A)(b) or Table 130.7(C)(15)(B), where applicable.
NFPA-70E-130.5(C) states the selection of PPE is to be determined by either 1) Incident Energy Analysis Method based on the working distance from prospective arc source, or by 2) the Arc Flash PPE Category Method utilizing the Table Method prescribed in 130.7(C)(15) & 130.7(C)(16).
NFPA-70E-130.5(D) states electrical equipment such as switchboards, panelboard, industrial control panels, meter socket enclosures, and motor control centers located in other than dwelling units and which are likely to require examination, adjustment, servicing, or maintenance while energized shall be field marked with a label containing:
- Nominal System Voltage
- Arc Flash Boundary
- At least one of the Following:
- Available incident energy and the corresponding working distance, or the arc flash PPE category as determined by Table 130.7(C)(15)(A)(b) or 130.7(C)(15)(B)
- Minimum arc rating of clothing
- Site-Specific level of PPE
Who is responsible for Arc Flash Labeling?
NFPA-70E-130.3(D) states the owner of the electrical equipment shall be responsible for the documentation, installation, and maintenance of the field-marked label.
When are Arc Flash Labels required to be updated?
NFPA-70E(130.5(D) states “where the review of the arc flash hazard risk assessment identifies a change that renders the label inaccurate, the label shall be updated.”
Which Arc Flash Evaluation Method is right for me?
While NFPA-70E permits the used of the Table method for determining the Arc Flash Boundary, this method does not take into all of the characteristics unique to a given electrical installation that may have an effect on the actual incident energy at a given point in the system. As a result, a true calculation-based analysis provides greater accuracy in establishing the Arc Flash Boundary based on actual conditions, often resulting in lower PPE requirements when compared to the Table method.
Why is accuracy important in performing Arc Flash Evaluations?
The primary purpose of an Arch Flash Evaluation is to educate the employee or technician who is to perform work on the equipment, of the electrical hazards present. Using this information, that person then selects the appropriate PPE for the task. However, there is also an inherent risk associated with use of the PPE when working on energized equipment. As the protective rating of PPE increases, the flexibility and dexterity of the person wearing the equipment decreases, potentially increasing the overall risk of an arc flash incident occurring during the performance of work. Therefore, it is important to select the right PPE for the job.
A point calculation-based study takes into consideration the unique properties inherent to a system, resulting in greater accuracy in the determination of the incident energy and required arc flash boundary throughout the system. This means employees and technicians are armed with more accurate information enabling them to select the right PPE for the task, while maintaining optimal dexterity and flexibility while using the PPE. As a result, the overall safety measures are improved.