The information in the hazard/risk tables in NFPA 70E represents an experienced based opinion of a task group comprising representatives of all segments of our industry. Notes containing a list of parameters that describe to conditions under which the tables apply follow the tables. The notes describe the limits of the conditions for the tables. The content of the tables is not connected to any calculations.
Having made that point, it is my opinion that the tables do provide adequate protection for employees. The tables have been included in NFPA 70E since the 2000 edition was published. About one half of the community using NFPA 70E define requirements based on the content of the tables. Some, but not all, apply the tables within the parameters defined by the notes. In excess of 50,000 copies of NPFA 70E have been purchased since the tables were inserted. No injuries have been reported to workers who were protected as defined in the tables. I am not sure that I would say categorically that the tables provide adequate protection, however, it has been my experience that the tables are adequate.
Any worker who is exposed or may be exposed to an electrical hazard should be trained to understand how and when exposure exists. No one needs NFPA 70E training. However, most people need training related to electrical hazards and work practices. NFPA 70E suggests that workers should be qualified to execute their assignment, regardless of what the assignment is. Workers assigned to different jobs might have different levels of exposure, but each worker needs to understand that exposure and be able to select a work practice that eliminates the risk of injury that might result.
Generally, designers and design engineers are not exposed to electrical hazards. However, the product of their work has a major influence on if, how, and when workers in the field may be exposed to an electrical hazard. Field workers need to have switching flexibility to create an electrically safe work condition for every piece of electrical equipment. Sometimes that means additional switching opportunities to continue with production while one part of the system is being repaired or maintained.
Since the 1995 edition of NFPA 70E was published, arc flash has been recognized an electrical hazard that hurts people. When equipment is specified that requires a door to be opened to operate a switch or circuit breaker, the worker is exposed to an arc flash hazard. When equipment has ventilation louvers in the door, workers who operate the handle or push a "close" or "open" button mounted on the door are exposed to an arc flash hazard. When equipment is specified that has inadequate barriers between sections or switching devices, a worker is exposed to shock or electrocution when the door is opened and flame migration in an arcing fault.
Designers and design engineers should begin to think about the purpose of circuit protection as protection to people instead of protection for conductors and equipment. The design should result in the minimum available fault energy (arc flash) at all points in the system that might require adjustment, repair, or maintenance. Designers and design engineers should always consider arc resistant switchgear.
Designers and design engineers should anticipate the tasks that will or may be required in the field. They should anticipate the result of a hazard/risk analysis and implement a design that protects both the equipment and the field workers.
1. Ability to create an electrically safe work condition
2. Minimize available arc flash energy.
3. Expose test points and adjustments to the outside of equipment to avoid the need to open a door or remove a cover.
4. Provide adequate barriers to segregate sections and devices and avoid potential for shock or electrocution.
5. Talk with operator and maintenance workers
6. See above question
The intent of the device is to sense a low level arcing fault. My experience has been in an industrial setting so I have no first hand experience with AFCIs. I have experience, however, which says that low-level arcing faults sometimes result in fires. Low-level arcing faults have a history of igniting fires in heat tracing applications. However, I have no basis to express a valid opinion for residential and commercial application of AFCIs.
NFPA 70E identifies some conditions under which an energized work permit is not required for each exposure to an electrical hazard. Testing for absence of voltage is one of those conditions and diagnostics is another. However, the exception is not so freewheeling. Workers who perform these tasks must be qualified for the specific task to be performed. To be qualified for the task as defined in NFPA 70E, workers must receive training as defined by Article 110.
I do not understand the question. However, the comment is correct that an accurate measure of the wire size is critical regardless of the type of insulating material. Several manufacturers provide wire gauges that are accurate. However, the conductor must be in an electrically safe work condition to use a wire gauge.
The question suggests that an electrical supervisor might have different personal responsibility in an institutional environment. Electrical supervisors are representatives of the employer regardless of the work environment. Personal responsibility has more than one aspect and is not dependant on industrial segment. His or her responsibility has a moral and ethical characteristic in addition to a legal characteristic. In my opinion, the personal responsibility is universal.
This question has two aspects. First, a balaclava, hardhat, face shield, and chin cup are not the same as a double layer-switching hood. Second, the real issue is whether the combination of protective devices will provide the necessary thermal protection. Employers must determine if the protection is equivalent or not. Manufacturers can help by testing individual components. They might also test various combinations. However, the employer is responsible to make the determination. Note that the protection provided by the overall combination is only as good as the weakest component and that arc rated hard hats are not available to my knowledge.
1. Worker error
2. Contact with overhead lines
3. Inadequate maintenance
The question does not indicate what "comply" refers to. If the question is related to OSHA regulations, the answer is no.
If the question is related to NFPA 70E, the answer is also no. However, NFPA 70E requires a hazard/risk analysis. NFPA 70E also requires a label on specific equipment that contains an arc flash hazard. One component of a hazard/risk analysis is determining if the worker might be exposed to a thermal hazard. Another component is if the worker might be exposed to shock or electrocution. One way to determine if an arc flash hazard exists is to perform an arc flash study.
This question is not directly related to an electrical hazard. I do not feel qualified to provide an answer to the question.
I am not sure that a "correct" method exists for working on energized circuits in the service industry any more than in any other industry. Except in rare instances, if the source of energy is 100 kVA or less, workers in the service industry are not exposed to significant levels of arc flash or arc blast. However, if the voltage level is 50 volts or greater, workers are exposed to shock and electrocution. Both NFPA 70E and OSHA Subpart S define requirements that attempt to mitigate the exposure. Service industry technicians are required to be qualified workers, as defined in NFPA 70E, and to select and use work practices to mitigate exposure to the hazard and to use PPE to necessary to prevent injury.
The objective of NFPA 70E is to eliminate all hazards and risks associated with electrical energy. At the same time, the NFPA 70E Technical Committee recognizes that the circuit or equipment must be energized for some tasks to be performed, taking a current reading for instance. NFPA 70E embraces strategies intended to enable this type of work to be performed while affording protective measures to mitigate potential exposure to the electrical hazards. For instance, the standard defines training that is necessary for a worker to be considered qualified to perform any assigned work task. The standard also identifies protective equipment that might be necessary. It also identifies certain administrative measures that should be taken to mitigate exposure to electrical hazards.
Note that electrical hazards are not related to equipment. The hazards always exist. The manner of exposure to the hazard is related to equipment and the degree of each hazard is dependant on the parameters associated with the hazard.
If the question means "flame retardant clothing," it is misapplied in this question. That term is related to bedding and children's sleepwear.
The need for arc rated flame resistant protective clothing and equipment depends on whether workers might be exposed to an arc flash hazard. If workers are in the employ of a small contractor, they should be provided with the same degree of protection as a large contractor. Protection is necessary to prevent injury. As a matter of fact, insurance rates that small and large contractors pay is based on the track record of injuries. In most cases, the cost of the protective equipment is returned several times over should a single injury occur.
OSHA has a course that provides a certificate. To my knowledge, no other certification is available. For this reason, employers must pay close attention to the qualification of any consultant engaged to provide training.
The question does not define the referenced standard. If the reference is to OSHA, I am not sure that compliant is the correct term. If the reference is to NFPA 70E, the applicable requirement is for a hazard/risk analysis. If an employer chooses to use the Meltric plugs as a disconnecting means, then the employer must be able to defend that choice.
No. The referenced final rule is based on NFPA 70E. Although some of the OSHA requirements might be identical to NFPA 70E requirements, only the OSHA standards are "law" in the legal sense. However, the general duty clause of the OSH Act requires employers to provide a workplace that is free from recognized hazards. As an American National Standard, hazards discussed in NFPA 70E are recognized hazards.
To say it succinctly, the performance language of the OSHA standards describes what is required and NFPA 70E describes one way to achieve the OSHA requirement.
When the electrical equipment or circuit is in an electrically safe work condition, no hazard exists. Consequently, no PPE is necessary. Note, however, that lockout/tagout as described in the OSHA regulations in either 1910.147 or 1910.333 does not create an electrically safe work condition.
I am not familiar with the term decontactor.
This question is complex and more information is needed to provide an answer. I would be happy to talk with this questioner off line.
This question does not provide enough information for an answer. Several good books are available. Both NFPA 70E and an NFPA 70E handbook are available. See the NFPA catalog or visit their web site are www.nfpa.org.
The electrical hazard associated with cable inspection and the possibility of limited or contaminated air in a manhole is not related. The NFPA 70E tables are default conditions based on the experience of the Technical Committee. I believe that a manhole (which a person enters) is a confined space as defined in the OSHA standards. However, I am not an expert on hazards associated with confined spaces.
NPFA 70E is a voluntary standard. It is not a legal requirement. However, OSHA's standards are written in performance language. The general duty clause of the OSH Act requires an employer to provide a workplace that is free from recognized hazards. As an American National Standard, NFPA 70E identifies hazards and specific suggestions about how to avoid them. As such, a violation of the general duty clause could be the source of a citation when an employer does not address recognized hazards.
The answer to this question depends on whether the person opening the door or taking the photograph is within the flash protection boundary or within the restricted approach boundary. Any person within either of these boundaries must be protected.
Electricians should wear class E rated hard hats. The current classification system replaced an older system in recent years. The class E rated hardhat is equivalent to hard hats that were rated as class B.
No. The effort is continuing and some tests are currently being planned. A project manager has been engaged and the testing process is underway.
This question is related to the NEC. Since my expertise is related to NFPA 70E, I prefer to not answer this question.
A great deal of work is necessary to shift an existing culture from one perspective to another. Workers tend to follow the lead of managers and supervisors. Workers are very astute and sense both motives and interests of the corporate line organization. The first step then is for supervisors and managers to exhibit a real passion for safety. The second step is for the corporation to provide a program that defines policies, procedures, programs, training, protective equipment, auditing, and other elements that provide direction for workers. The third step is to enforce requirements that are necessary to avoid injuries. The fourth step is to continually review and modify any portion of the program that is not working or working less than satisfactorily. I recommend a book published by Jones and Bartlett and available from either Jones and Bartlett or NFPA titled Electrical Safety in the Workplace. This book provides a detailed discussion about building an electrical safety culture.
Yes!!! Literally hundreds of burn injuries have been prevented.
If the question means NFPA, the answer is yes. NFPA 70 is known as the NEC and it does apply to residential installations.
NPFA 70E, on the other hand, addresses work practices wherever workers are or may be exposed to an electrical hazard. If workers are exposed to an electrical hazard in residential construction, then NFPA 70E may be used.
NFPA 70E Annex J illustrates one energized work permit. This form can be photocopied and used. The content of the permit can be placed on a computer and used in that form. A book titled Implementing the Electrical Safety Program, published by and available from Jones and Bartlett or available from NFPA contains a compact disc with a form already designed and ready for printing.
I am not sure that OSHA requires electrical equipment to be tested before being returned to service. However, OSHA does require cord sets, and electrical hand tools such as drill motors in addition to some PPE to be tested before return to service. In these instances, I believe that the intent is for the test to ensure that the protective nature of the equipment or system is restored to its original protective ability. In cord sets, that means that a worker will not be exposed to shock or electrocution. In voltage rated PPE, it means that the PPE is subjected to defined tests.
I am not sure how much regulation is enough. I think about regulation this way.
To function as a society, rules must be established and followed with enforcement, where demanded by society. When the amount of regulation reaches the level where society can function rationally, then the amount of regulation has reached the necessary level. However, when the social network begins to deteriorate, the amount of regulation is not enough.
On the surface, micromanagement is undesirable. Workers (and other members of society) should be able to make decisions, reach conclusions, and take actions without direction. In most instances, managers and supervisors have information about objectives that workers do not have. Managers, supervisors, workers, and other leaders view any specific situation from different perspectives. In some instances, to achieve a timely result, micromanaging might be the only rational choice. However, our society (specifically in a single workplace) should be working to provide the necessary training related to worker safety together with the necessary protective measures to avoid any need for continuous direction.
If the gist of the question is related to NFPA 70E, the answer shifts a little. NFPA 70E provides guidance that should enable workers and supervisors to make sound decisions and choices. Strategies, which are inherent in NPFA 70E, provide guidance and direction, which saves lives. Note that the standard is voluntary. Other standards might provide adequate guidance regarding an electrical hazard and employers are welcome to choose one. Implementing the requirements in NFPA 70E is "macro" managing. When the program defined within the standard is functioning, micromanagement is neither necessary nor desirable.
The answer to this question depends on the result of the hazard/risk analysis associated with the task of checking for absence of voltage. If the worker will not penetrate the flash protection boundary, then no flash protection is required. If the worker cannot penetrate the prohibited approach boundary, then no shock protective equipment is necessary unless the employers program required shock protection within the restricted approach boundary. However, the hazard/risk analysis must also consider the characteristics of the voltage tester. Many injuries occur because some aspect of the voltage tester was inadequate. Leads can fail. Voltmeters can fail. Static discharges are possible. If the voltmeter meets the requirements of UL 1244 and ANSI/ISA S82.02.01, and the visual inspection indicates no damage, then shock protection is not necessary.
Any component that is intended to protect workers from the thermal hazard associated with an arcing fault must be rated in terms of Arc Thermal Performance Value (ATPV). The ATPV rating is intended to compare directly with incident energy. The ATPV must equal or exceed the expected incident energy level.
The NEC (and chapter 4 of NFPA 70E) requires a label on specific equipment. However, the intent of a label is to provide warning to workers that an arc flash hazard exists within the equipment. To comply with "the letter of the law" then, only the specific equipment listed in section 110.16 of the NEC must have a label. However, to comply with the intent of the label, any equipment that contains an arc flash hazard such that a worker would be exposed when the door is opened must have a warning label.
The ROC meeting of the Technical Committee is scheduled for October 1, 2007 in San Diego. When the review process is completed, the standard will be presented to the Association in the annual meeting in 2008. The 2009 edition of the standard will become effective on January 1, 2009.
I am not sure how much regulation is necessary. I am sure that common sense varies widely among knowledgeable and thoughtful people. I am also certain that common sense changes from decade to decade. I am certain that technology, equipment, and experience change between decades. I am also certain that person's principles change with growth in understanding. Likewise, I am certain that common sense work practices change from time to time. I might add that change varies among people of the same generation.
Regulations related to safety, the OSHA rules for instance, are a response to statistical experience. For instance, when the OSH Act was generated, many thousand workers were being injured on the job each year. The incidents and injuries caused pain and suffering and reduction of the GDP, which exceeded all losses resulting from labor strikes. NFPA 70E and similar voluntary standards are an attempt by society to support and enhance the regulations. When 70E-1995 was published, electrocution was the fourth leading cause of industrial fatalities. Arc flash injuries were not on the map, but experience shows that up to 80 percent of electrical injuries were thermal burns from exposure to an arcing fault.
As a democratic society, we embrace the will of the majority. When regulation becomes overbearing for the majority of our society, then society will demand that the amount of regulation be reduced. Corporations are not democratic societies. Although some of the most successful corporations function essentially as a democratic society, the majority of US corporations are autocratic. The leaders an autocratic society may or may not be mindful of the risk that workers take as they construct, operate, and/or maintain corporate facilities. Regulation is necessary to meld the needs of our general democratic society and the corporate autocratic society and enable both to function. Autocratic corporations operate with the permission and support of the general society. Only our general society can determine when too much regulation exists.
States recognize needs and attempt to respond to those needs. The federal government does the same thing, albeit with a different perspective. Federal and state regulations result from attempts to respond to recognized needs. Our system is not perfect by any means. However, it is what we have.
If the gist of the comment is related to NFPA 70E, the standard is a public document. It is written by the public, reviewed by the public, and modified by the public. Additionally, NFPA 70E is a national standard. It is intended to serve the needs of society. As such, membership in the Technical Committee is representative of society. Some members of the Technical Committee disagree with much of the content; however, a supermajority of the Technical Committee is required to make any change in the standard. Therefore, a supermajority of the Technical Committee supports all contents of the standard. Note that any member of the public may submit proposals to change the requirements and comments about any action taken by the technical committee.
I must make some assumptions to answer this question. Two types of hand tools are available. They are insulated and insulating. Insulated hand tools are ordinary hand tools that have an electrical insulating material applied to them. They are rated at 1000 volts and marked with the double triangle. Insulating hand tools are those that are constructed of insulating material such as hot sticks. The rating of insulating hand tools may vary and is established by the insulating value and the length of the material of construction.
I remember a time earlier in my career when we would purchase plastic handles to install on pliers. I remember thinking that the plastic handles provided insulation and would help prevent being shocked. NOT TRUE. Adding the plastic handles on pliers provides a significant difference in how a worker's hand feels when using the pliers. However, the comfort handles do not prevent shock or electrocution.
If an electrician is pulling wire into a spare conduit inside a "hot" 480 277V panel but the dead front is still on, what level is this and what PPE is required?
The question does not indicate if the word "hot" means electrically energized or that the temperature of the panel is elevated. Just kidding, but some people truly do not understand since the term "hot" has multiple meanings. In our business, we should talk about energized or de-energized. By the way, when we use the term "dead" to describe a circuit to be touched, sometimes the term can accurately be applied to the worker.
NFPA 70E would say that the worker must perform a hazard/risk analysis and then react to the exposures uncovered in the analysis. The worker should consider arc flash and ask himself or herself if an arcing fault occurred inside the equipment, would he or she be exposed to the resulting thermal hazard. The potential for an arcing fault exists if the spare conduit enters the equipment in a place such that the fish tape could contact any energized conductor. The worker should consider if he or she could receive a shock or be electrocuted as a result of the fish tape contacting an energized conductor. Is the fish tape metal? Does the fish tape have a metal end? Is the equipment wireway segregated from any open conductor? What is the incident energy level at the location of the conduit penetration? Can the panel be deenergized? What is the flash protection boundary? Is the equipment arc resistant?
No prescribed answer exists to this question. Only by considering the work task and the state and condition of the equipment and asking questions such as these can a worker arrive at a logical conclusion.
Yes.
This question cannot be answered.
Maybe. The hazard/risk analysis determines what hazards are associated with the work task. If the worker is exposed to shock and electrocution, he or she should be wearing voltage rated gloves. For the voltage range in question, the voltage rated gloves must be at least Class 00. If the worker must penetrate the flash protection boundary, the part of the body that is within this boundary should be protected from the available incident energy.
Current flow is the actual movement of electrons. As the potential changes to reverse the higher potential to the lower potential, the movement of electrons also reverses direction. As electricians, we talk about current flow and voltage. Physics professionals talk about electron flow and potential. Although the terms of conversation are different, the issue is the same. So, yes. The flow of current actually reverses direction.
The rating of protective clothing (and some other components) is called Arc Thermal Protective Value (ATPV). The rating indicates that the clothing component will protect a person from any arc thermal exposure up to the rating of the component. ATPV is stated in calories per square centimeter. Calories are a measure of heat and a square centimeter is a square area that is one centimeter on each side. Therefore, the rating defines how much thermal energy the protective component might absorb and safely dissipate.
The number is important because, incident energy levels are also stated in terms of calories per square centimeter. An incident energy rating is the amount of thermal energy that might be available at any point in the system should an arcing fault occur.
The two numbers, ATPV and incident energy, are intended to provide a worker with the ability to know that his or her protective equipment will avoid an injury greater than a second-degree burn. The ATPV rating (thermal protection) must be at least equal to the incident energy (possible thermal energy).
The table 130.7(C)(9)(a) lists work tasks instead of equipment. The tasks are collated on the basis of a class of equipment. Therefore, safety disconnects as such, are not classified in the table. Work tasks associated with the disconnect switches and circuit breakers are contained in the table.
More information is needed before I can able to offer an opinion on this question. I would be happy to talk with the questioner off line.
If I install medium voltage shielded cable under ground-concrete incased can I also install control wires in the same trench? What should be the space between?
This question is related to installation and is covered in either the NEC or the NESC dependant upon the use of the conductors. The answer can be found in one of those codes. NFPA 70E does not address this issue.
The quality and effectiveness of the insulating material determines the ability of the tool to minimize the risk of electrocution. The insulating material might impact the risk of initiating an arcing fault.
The thermal hazard associated with an arc flash event was recognized in consensus standards with the publication of NFPA 70E-1995. Prior to 1995, consensus standards only addressed shock, electrocution, and fire. Electrical burns account for about 80 percent of all electrical injuries and the attention is resulting in a reduction in burns. Although electrocution accounts for the majority of fatalities, burns account for injuries with long-term implications. So, yes, the value is real.
NFPA 70E addresses work practices associated with electrical hazards. Consequently, the standard does not differentiate between residential workplaces, commercial workplaces, and industrial work places. Personal protective equipment must be selected based on hazards and worker exposure to them. The standard suggests that workers should perform a hazard/risk analysis and then use the protective equipment that will provide the necessary protection to avoid injury.
NPFA 70E is a standard. Unlike a code, requirements defined in the standard are not required, as such. Instead, the standard identifies recognized hazards and work practices necessary to avoid injury. Employers are free to choose a different standard or to generate their own. However, if a hazard is recognized in a national consensus standard, such as NFPA 70E, the general duty clause of the OSH Act expects employers to take some action to avoid injury from the hazard.
I am not familiar with the source of the statistic quoted in the question. However, the majority of injuries result from worker action. Whether the injury or incident resulted from a careless mistake, a known risk, or from inadequate understanding of the hazard might be debatable. After an injury has occurred, the injury becomes the most important issue. Employers should take steps as outlined in NFPA 70E before an incident or injury happens.
NFPA 70E requires an electrical safety program. One element of the required program is procedures. The standard does not define what procedures are necessary. The standard does indicate that the procedures should provide direction for workers that are necessary to avoid injury.
To perform calculations at a point in a circuit requires significant amount of information about the source of energy. It is unlikely that service technicians have access to the necessary information. NFPA 70E establishes default recommendations to protect workers. The table contained in the standard defines default protective equipment.
The most severe thermal injuries occur when a worker's clothing ignites and burns. Generally, the overcurrent protective device will remove the source of energy in a short period of time. When clothing ignites, the worker is exposed to the burning clothing for several minutes. Equipment serviced by service technicians tends to be supplied from circuits with limited capacity. If the capacity of the circuit is less than 100 kVA, the flash protection boundary is short in most cases. I recommend that service technicians wear heavy-duty leather gloves in all cases where exposure to a potentially energized electrical circuit is possible. I also recommend that all service technicians wear clothing that has an arc rated ATPV rating of category 2 in all cases. Although the category 2 protective clothing might not prevent a burn injury, it will not ignite.
All current methods of performing incident energy calculations are based on a distance of 18 inches or 36 inches, depending on the equations that are used. These dimensions were selected on the basis that a worker's body would be at about those distances. Of course, the worker's hands are likely to be closer than those distances. Consequently, eliminating the risk of a thermal injury to a worker's hands requires greater protection.
The current state of estimating incident energy and protective equipment is that no realistic method exists to estimate the energy to which a worker's hands will be exposed. Experience suggests that heavy-duty leather gloves, such as those provided with voltage rated gloves, provide relatively good protection. Tests are currently underway that intends to provide improved methods of estimating exposure to the thermal hazard and others such as the pressure wave that accompanies an arcing fault.
It is important to remember that all current methods of calculating incident energy have limitations, some of them significant. For instance, some methods only consider single-phase faults.
NFPA 70E does not require an arc flash study. Instead, the standard requires a hazard/risk analysis. The standard permits an employer to choose the method to determine incident energy and the protective equipment necessary to avoid thermal injury. An arc flash study is one way to execute part of the hazard/risk analysis.
Like all safety incidents and injuries, electrical incidents and injuries may be categorized in terms of root cause. The categories might be considered to be unsafe equipment, unsafe conditions, and unsafe work practices. In terms of percent, all three categories will add up to 100%. Unsafe equipment amounts to roughly 16.5 %, unsafe equipment amounts to roughly 16.5 %, and unsafe work practices amounts to the remaining 67%.
Note that NFPA 70E addresses work practices.
Electricians need to know about the employer's electrical safety program where one exists. If the employer does not have an electrical safety program, electricians need to become familiar with electrical hazards and how to protect themselves from those hazards. NFPA 70E is an important part of the process that discusses electrical hazards and the mechanics of protection including both work practices and PPE. I recommend that electricians read the content of the standard and consider their familiarity with the information presented in the standard. If the employer does not have an electrical safety program, electricians should request that the employer provide one.
Many articles and technical papers have been written and published discussing the thermal hazard associated with an arcing fault. The IEEE – IAS Electrical Safety Workshop and the IEEE PCIC Electrical Subcommittee have been particularly active in providing information about the subject. Several books discuss the subject as well, although not in as much detail as the technical papers. Electrical Safety in the Workplace and The Electrical Safety Program Book published by Jones and Bartlett both contain chapters that discuss electrical hazards, including arc flash. However, all current information is interim. Research and testing is currently happening, which will provide additional information. Stay tuned for new information.
I would be happy to talk about fire alarms as they relate to arcing faults off line.
The need for protective equipment suggested in the question depends upon the amount of energy that is available in the circuit. If the transformer providing the electrical energy is less than 100 kVA, the flash protection boundary that triggers the need for protective equipment is significantly reduced. If the covers are all in place when the circuit breaker is reset, any exposure to a thermal hazard is very limited. If it is any help, I have a 75 kVA transformer providing energy to my house and I do not wear protective equipment when resetting a circuit breaker.
Electrical equipment is tested to withstand a bolted fault. Unless the equipment is arc resistant, no tests have been conducted under arcing fault conditions. NFPA 70E-2004 suggests that exposure to a thermal hazard exists when work is performed within the flash protection boundary. A flash protection boundary exists when energized electrical conductors are exposed. Normally, equipment such as panelboards or MCC that are closed and latched as intended by the manufacturer and protected by current limiting devices will not expose a worker to a thermal hazard when the operating handle is moved from one position to another. Note however, if the door or cover contains holes or ventilation louvers the electrical conductors are exposed to contact through the holes or louvers creating a flash protection boundary and triggering a need for thermal protection.
It is possible that an internal fault in a MCC can contain sufficient energy to destroy the integrity of the enclosure. The risk is significantly reduced if current limiting devices protect the MCC supply conductors.
No. I anticipate that NFPA 70E will continue to be viewed as a standard instead of a code. I expect that state OSHA organizations will follow the lead of the Federal OSHA.
Yes. NFPA 70E is being enforced in some instances. For instance, the Department of Energy adopted the standard for use by all facilities and contractors. NFPA 70E is federal law in Brazil. Some corporations have adopted NFPA 70E for use internally. As a standard, the document is available for use by organizations and other entities. It is not enforceable until it is adopted.
I recommend the Handbook for Electrical Safety in the Workplace. The book contains the text of the standard and provides discussion about each requirement. The discussion attempts to provide insight into the intent for the requirement. The handbook is available from Jones and Bartlett or from NFPA.
I also recommend that another book called Implementing the Electrical Safety Program also published by Jones and Bartlett.
The need for PPE is triggered when work is performed within the flash protection boundary as defined in NFPA 70E. The issue then translates to "does the cover on the line side terminals provide adequate protection?" Some equipment has adequate barriers for the line side terminals and other equipment does not. When the hazard/risk analysis is performed, the adequacy of the terminal covers must be assessed.