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Frequently Asked Questions

Arc Flash

Q: How common are arc flash incidents and related injuries? Approximately how many fatal and non-fatal arc flash incidents occur annually?

A: Arc flash incidents are fairly common with many serious injuries and fatalities reported. According to the NFPA 70E, arc flash incidents and the related burns "make up the majority of hospital admissions due to electrical accidents" (rather than shocks). Further, more than 2,000 people are admitted to intensive care burn units each year as a result of severe arc flash burns they received during an arc flash incident. Fatalities occur at a rate of approximately one per day in the United States with non-fatal arc flash incidents occurring approximately 5-10 times per day. Even these non-fatal arc flash incidents consistently result in many serious burns and injuries requiring weeks to months of intensive care hospital stays and many months of painful rehabilitation.

Q: What businesses and facilities are required to have an arc flash analysis?

A: Nearly every facility that uses electrical distribution systems and/or equipment is required to have an arc flash engineering study performed. Basically, any facility where an individual might be exposed to electrical hazards and the possible danger associated with arc flash exists requires a study. In addition to industry and manufacturing plants, this also includes facilities such as hospitals and schools

Q: If I only have a small facility and an outside electrical contractor does the majority of our maintenance and testing work, can I avoid having to set up a safety program for arc flash protection or forego an engineered study?

A: The size of the facility is not the determining factor in who needs these arc flash engineering studies and electrical safety programs. You cannot circumvent the requirements for an electrical safety program and an arc flash engineering study. Further, the cost for performing such an engineering analysis for a small facility will be extremely low compared to the costs to your business as the result of an electrical accident involving one of your contractor employees. The host employer will generally be responsible for making sure that adequate electrical safety measures have been taken to protect and warn your contract employers from the known hazards of your facility, arc flash included.

Q: Must an arc flash hazard analysis be conducted at a facility even if the employees never work on energized of live electrical equipment?

A: Yes. Even if a facility's employees themselves do not work on such equipment, the dangers of arc flash still exist, and it is likely that outside contractors are brought in to perform routine maintenance or repairs. It is the responsibility of the host employer to have an arc flash analysis in order to determine the hazard category level of a given panel or piece of electrical equipment that an outside electrical contractor may work on. It is this determination through the arc flash engineering study that alerts the contractor of the incident energy level and related level of personal protective equipment (PPE) that is required to be worn while performing the designated tasks.

Q: Are there particular types of industries, businesses, or facilities that generally have a higher incident rate of arc flash or arc blast incidents?

A: The working practices and the training of specific individuals involved in the arc flash and arc blast incidents along with company policy regarding energized work play the greatest roles in determining the rates of incidence. Arc flash incidents can occur in any type of industry and don't discriminate based on facility as much as they do on work practices.

Q: Do the arc flash standards and required engineering studies apply to all panels regardless of size, such as those in small businesses, machine shops, or homes?

A: The requirements for an arc flash analysis apply to any equipment that operates at 50V or greater. Arc flash studies are not required in homes that are single-family residences. 

Q: If a subcontractor is working in a commercial building, which entity is responsible for providing the arc flash analysis for the subcontractor? Is it the host/management company or the subcontractor?

A: The building owner/host employer is generally responsible for the analysis. The electrical contractor has to follow the safety requirements of the host employer and utilize all electrical safe working practices of the NFPA 70E.

Q: What type of arc flashes might I experience if I am working on strictly on 120/208V lighting panels?

A: You can experience the same types of arcing fault and bolted fault that are present in larger panels. The incident energy may typically be lower when working on these types of panels, but it does depend on a number of factors such as size and type of conductor, wire length, as well as breaker type and operating speed, presence of a main breaker, etc.

Q: Can an arc flash occur while changing 120V outlets?

A: Though an arc flash is not the primary concern when dealing with 120V outlets, the circuit breaker feeding that outlet should be switched off in order to minimize the shock hazard.

Q: How is the Arc Flash Boundary calculated?

A: The Arc Flash Boundary is one of the things that is calculated during the arc flash engineering study. It is determined by the distance from the source of an arc flash where the incident energy is 1.2 calories per square centimeter. This incident energy refers to the amount of energy which results in a second-degree burn. 

Q: How does equipment maintenance (and in particular, that of older equipment) factor into the dangers of arc flash or other electrical hazards?

A: Equipment that is not properly maintained, and particularly older equipment (as you reference), presents an increased risk of experiencing an arc flash incident or other electrical hazard-related event. Older, poorly-maintained pieces of equipment are essentially accidents waiting to happen. Proper equipment maintenance is one of the most important things that facilities can do to reduce the likelihood of experiencing an arc flash incident along with strongly enforcing safe-working practices.

Q: Frequently, we are seeing utility service providers with increasingly higher available short circuit current. In some cases, the utility is providing short circuit current that exceeds the rating of the equipment or main services that have already been in place for many years. How does this increased available short circuit current affect the dangers of arc flash incidents?

A: This is becoming an increasing problem where equipment and main services are being "overdutied" so that the fault duty rating is insufficient to handle the available fault current. Often, these are changes made by the utility service provider without any notification to the customer. These are items that get reported during an arc flash engineering study and one of the main reasons why the required utility letters from the service provider are so important when performing one of these engineering studies.

Q: I noticed that hearing protection is often required in the regulations. What type of ear plugs are required by the NFPA 70E standard? Are they required to be FR-rated and non-melting?

A: Ear canal inserts are the standard ear plugs required in the PPE tables for the NFPA 70E. The requirement of wearing a wraparound face shield for most PPE requirements removes this issue of melting ear plugs and is not usually the primary concern since the inserts are not typically exposed to the high-heat conditions during an arc flash. When wearing the wraparound face shield, the inserts should not be exposed as the arc passes around it.

Q: I noticed that hearing protection is often required in the regulations. What type of ear plugs are required by the NFPA 70E standard? Are they required to be FR-rated and non-melting?

A: Ear canal inserts are the standard ear plugs required in the PPE tables for the NFPA 70E. The requirement of wearing a wraparound face shield for most PPE requirements removes this issue of melting ear plugs and is not usually the primary concern since the inserts are not typically exposed to the high-heat conditions during an arc flash. When wearing the wraparound face shield, the inserts should not be exposed as the arc passes around it.

Safety Compliance

Q: Is the topic of safe electrical working practices included in the OSHA electrical standard and where can this OSHA standard for electrical work be found?

A: The 29 CFR 1910 Subpart S deals with the general industry regulations regarding electrical safety. The OSHA standard itself does not provide the specific information regarding safe working practices, that information is what is included in the NFPA 70E industry consensus document. OSHA uses the NFPA 70E to determine compliance with their 29 CFR 1910 regulations.

Q: Is the NFPA 70E an OSHA standard?

A: The NFPA 70E is an industry consensus standard that is used to show compliance with the OSHA requirements (federal regulations).

Q: How does OSHA use the NFPA 70E? Is this a document they endorse and enforce and is noncompliance with the NFPA 70E something that OSHA issues citations for?

A: OSHA has utilized the NFPA 70E since its inception in 1978. OSHA utilizes the NFPA 70E as an enforcement and compliance document for justification of their citations. There are numerous documented cases where OSHA has issued extremely costly citations for facilities not complying with the NFPA 70E. The NFPA 70E, as an industry consensus standard, is a primary reference document for showing compliance or non-compliance with OSHA regulations regarding electrical hazards and electrically-safe working practices.

Q: Why do so many businesses, or for that matter electrical contractors, violate the OSHA requirements to de-energize and place equipment in an electrically-safe working condition?

A: This practice is extremely dangerous and the OSHA guidelines and exceptions are very clear and very limited in allowing this type of energized work. Those exceptions only cover interrupting life support systems, deactivating emergency alarm systems, and shutting down ventilation systems in hazardous locations. Other than those three items, no other justification can be made to work on energized equipment. The main excuse that companies will give is that they cannot sacrifice the production time that is required to follow the federal regulations to de-energize and place equipment in an electrically-safe working condition before performing service. This is not an appropriate justification for working on energized equipment. Further, any "live" electrical work requires the filing and use of an energized work permit.

Q: What types of electrical work can I do without having an outside electrical contractor come in?

A: This depends on your level of training, knowledge, and experience. Trained electricians will typically be able to work on lighting and other small panels, but for larger panels and equipment, it depends on your working knowledge of the device and safe-working practices. The NFPA 70E requires that only "qualified persons" perform any work or service.

Q: How does an employer deal with employees who have a wide range of qualifications, from those who are only qualified to perform limited electrical work to those who do a wide range of electrical work and repairs?

A: Each employer is responsible for determining the qualifications of their employees. Qualified individuals are those who are trained and knowledgeable regarding the activities they are to perform and equipment they will be interacting with or working on. This includes the ability to recognize and identify hazards and being able to take measures to minimize those hazards.

Q: What employees are qualified to enter into electrical rooms, such as those that contain main switch gears and motor control centers?

A: Again, this depends on the training and knowledge of the individuals, and will be up to the company and their established electrical safety program to determine who is qualified to enter. Anyone that is unqualified or unaware of the hazards that exist should not be entering electrical rooms.

Q: Is the use of PPE required for troubleshooting tasks involving energized circuits?

A: Yes. The requirement for PPE is dictated by the available incident and hazard category level of the equipment being tested.

Q: Does executing a lockout/tagout require the use of PPE?

A: Yes. As part of the general lockout/tagout procedural requirements, the verification step requires that a qualified person physically verify the absence of electrical energy (to make sure a piece of equipment has been de-energized) before the equipment can be classified as being put in an electrically-safe working condition.

Q: If an employee opens an electrical cabinet that may contain both live and de-energized parts for the purpose of working on the de-energized components, is the employee still required to wear the designated level of PPE as determined by the hazard category of the equipment?

A: Yes. Wherever the possibility exists that an employee may be exposed to energized parts and related electrical hazards, even when they are not working directly on those parts, the appropriate level of PPE must be worn.

Q: If I have an individual from an outside contractor come into my facility to perform electrical work, who is responsible for providing the required PPE?

A: The outside contractor is an employer (of its employees) and is therefore responsible for the safety of their employees, which includes providing the appropriate level of PPE to its employees.

Safety Training

Q: Does the required safety training under the OSHA and NFPA 70E standards need to be documented?

A: Yes. The NFPA 70E requires that all safety training be documented and should include the name of the persons trained, the date, and the subject matter of the training.

Q: Do you offer any attendance documentation for people who attend your safety training sessions?

A: Archer Electric of Wisconsin provides personalized attendance verification sheets for the attendee and his or her employer, as well as training attendance verification wallet cards for each of the attendees. Both of these forms of documentation include the name of attendee, date of safety training, as well as the subject matter covered.

Q: How often must an employee receive electrical safety training?

A: The retraining requirements apply to any new equipment, new processes, or changes in the duties of an employee. Additionally, the new requirement in the NFPA 70E is that retraining is to occur no less than once every three years.

Q: I have attended other training sessions and have found the multiple approach boundaries to be complicated and difficult to understand. What is the difference between the four sets of boundaries and do we really need to know them?

A: The two types of boundaries that you are referring to are the Arc Flash Boundary and the set of three Shock Protection Boundaries = Limited, Restricted, and Prohibited Approaches. The NFPA 70E has clarified the flash protection boundary by renaming it the Arc Flash Boundary. It is important to understand that the boundaries are relevant to different things, with the Arc Flash Boundary being applicable to possible arc flash hazards; while the Limited, Restricted, and Prohibited Approach boundaries are related to electric shock hazards. To answer the other part of your question, YES. Electricians and qualified individuals need to know and understand what all of these boundaries mean.