The Occupational Safety and Health Administration (OSHA) requires that employers covered under the Occupational Safety and Health Act of 1970 provide employees an environment that is free from recognized hazards that cause, or are likely to cause, death or serious physical harm (OSHA 29 CFR 1926 and 1910, Section 1903.1).
OSHA provides electrical safety-related requirements that are essential for practically safeguarding construction employees in Subpart K of 1926. Subpart K, in its current arrangement, provides rules covering installation safety requirements, safety-related work practices, safety-related maintenance and environmental considerations, and safety requirements for equipment (OSHA 29 CFR 1926.400). These are the federal laws relative to electrical safety for construction workers. The National Fire Protection Association (NFPA) publishes NFPA 70E-2009, Standard for Electrical Safety in the Workplace. Essentially, this standard was developed at OSHA’s request to be compatible with its requirements related to electrical worker safety.
The first edition of NFPA 70E was developed in 1979, subsequent editions were published in 1981, 1983, 1988, 1995, 2000, 2004 and 2009. This standard addresses electrical safety requirements for employee workplaces during activities such as installation, operation, maintenance, demolition of electrical conductors, electric equipment, and communications and signaling conductors and equipment, according to 70E-2009, 90.2(A).
Contractor and worker responsibilities
Who is responsible for electrical worker safety? Safety for workers is as much an individual responsibility as an organizational one. OSHA clearly mandates employers provide a safe environment for workers. Understanding the rules and how to meet the minimum requirements is essential in the electrical contracting business. Electrical workers must understand the safety rules and know how to recognize and avoid the hazards involved.
To simplify what OSHA requires, electrical equipment shall not be worked on while energized. Energized work is permitted only if it has been determined that the task to be performed is not feasible in a de-energized state (e.g., voltage testing) or de-energizing introduces increased hazards. Working energized also has to be approved by someone in authority that accepts responsibility for such decisions. This is documented using an energized electrical work permit.
An important aspect of the decision to work energized should always include a careful analysis of the determination of what constitutes infeasibility, as compared to what might only be inconvenient. Many lose track of the difference. When the decision to work energized is reached, specific procedures, safety-related work practices, and requirements for documentation have to be followed. The basic procedures include disconnecting power, locking the disconnecting means and tagging it (lockout/tagout), and verifying the absence of voltage with an appropriate voltage detector and procedure. This voltage detection step typically involves use of suitable personal protective equipment while the absence of voltage is being verified.
Electrical contractors and workers both share in the responsibility to understand their electrical safety program and how to implement it to keep work environments safe. When in doubt, ask questions. The risks (individual and organizational) are too great to take chances. As a reminder, there have been no changes in these OSHA requirements and responsibilities. Now let’s move on to some of the revisions in 70E-2009.
Arrangement and Article 90 revisions
Article 90 of NFPA 70E is the introduction. It has been revised, expanded and organized to parallel the National Electrical Code (NEC) arrangement. Section 90.1 conveys the purpose of the standard, which is to provide a safe work area for employees relative to the electrical hazards. Section 90.2 provides what is covered in 90.2(A) and what is not covered in 90.2(B). The scope text in 90.2(A) has been clarified to indicate that 70E addresses electrical safety requirements for employee workplaces during activities such as installation, operation, maintenance and demolition of electrical conductors, electrical equipment, signaling and communications conductors, and equipment and raceways. Note that this revision clarifies 70E provides requirements related to safe work practices and activities, not installation rules.
A new Section 90.3 provides the arrangement of 70E and how each chapter is intended to be applied and describes the relationship between chapters. Chapter 1 applies generally. Chapter 2 applies to safety-related maintenance requirements. Chapter 3 covers safety requirements for special equipment (supplementing and modifying Chapter 1). Figure 90.3 graphically illustrates the structure of 70E-2009.
Chapter 4 no longer is included in NFPA 70E. Action by the 70E committee on Comments 719, 720, 721a and 722 to Proposal 520 resulted in the deletion of Chapter 4. Section 90.4 is the new location for the organization of NFPA 70E formerly provided in 90.2. Article 90 has also been expanded by incorporating 90.5 and 90.6 from the NEC into Article 90 of 70E. Section 90.5 provides users with information about terms used in mandatory rules, permissive rules and explanatory information typically in the form of fine print notes (FPN). Section 90.6 provides NFPA’s formal interpretation procedures in the NFPA Regulations Governing Committee Projects.
Article 100 definitions
The definitions in Article 100 have been revised to be consistent with the same defined terms contained in Article 100 of the NEC, and various new definitions have been introduced. A task group on words and phrases was established to revise certain terms in Article 100 and verify that consistent use of these terms was maintained throughout 70E. These changes resulted in requirements that mean what they imply by definition. In other words, the exact meaning of the rules in 70E is made clear through the use of defined terms. Action by the NFPA 70E committee on Proposal 70E-23 and Comment 70E-191a resulted in several new definitions being added to Article 100, which have been existing definitions in the NEC, but the terms are used within NFPA 70E.
The following provides a review of new definitions in Article 100 as well as some existing definitions that have been revised. The definitions are reprinted by permission of the NFPA:
• “Arc Flash Hazard. A dangerous condition associated with the possible release of energy caused by an electric arc”
“FPN No. 1: An arc flash hazard may exist when energized electrical conductors or circuit parts are exposed or when they are within equipment in a guarded or enclosed condition, provided a person is interacting with the equipment in such a manner that could cause an electric arc. Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard.”
This new fine print note to the definition of arc flash hazard differentiates between conditions where arcing conditions could result from the way workers are interacting with the equipment and those conditions where normal operating conditions are not likely to pose an arc flash hazard. This note is valuable in clarifying the scope language presented in revised Section 110.1.
“FPN No. 2: See Table 130.7(C)(9) for examples of activities that could pose an arc flash hazard.”
“FPN No. 3: See 130.3 for arc flash hazard analysis information.”
“Arc Rating. The value attributed to materials that describes their performance to exposure to an electrical arc discharge. The arc rating is expressed in calories per cm2 and is derived from the determined value of the thermal performance value (ATPV) or energy of breakopen threshold (EBT) (should a material system exhibit a breakopen response below the ATPV value) derived from the determined value of ATPV or EBT.”
• “Balaclava (Sock Hood). An arc-rated flame-resistant hood that protects the neck and head except for facial area of the eyes and nose”
• “Boundary, Arc Flash Protection. When an arc flash hazard exists, an 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”
• “Switchgear, Arc-Resistant. Equipment designed to withstand the effects of an internal arcing fault and that directs the internally released energy away from the employee.”
Since arc-resistant equipment that is closed and latched as intended by the manufacturer diverts the thermal energy away from the front of the equipment, no arc flash protection boundary exists. Because no arc flash protection boundary exists in front of the equipment, no protective equipment is necessary, but only as long as the equipment cover is closed and properly latched. As soon as a door is opened, an arc flash boundary is created. This type of switchgear is typically available in the medium voltage levels. Specifying this type of equipment in electrical designs can help reduce arc flash hazards but installers should still exercise caution and use appropriate applicable safety-related work practices consistent with their electrical safety program.
• “Working On (Energized Electrical Conductors or Circuit Parts). 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 a person is wearing.
There are two categories of working on:
Diagnostic (testing)—taking readings or measurements of electrical equipment with approved test equipment that does not require making any physical change to the equipment.
Repair—any physical alteration of electrical equipment (such as making or tightening connections, removing or replacing components, etc.)”
The definition of the term “working on” clarifies that this is a condition of contact with energized electrical circuit conductors or circuit parts that is different than those workers who are not in contact but are within the approach boundary and are required to be protected based on the incident energy level present.
Action by the NFPA 70E Technical Committee on Proposal 70E-19 and Comments 70E-212, 223, 225 and 226 result in restructuring the boundary definitions in a clearer, more usable format. Essentially the words “exposed live parts” have been replaced by the words “exposed energized electrical conductor(s) or circuit part(s)” as a result of the work of the assigned task group on words and phrases.
Article 110 General Requirements for Electrical Safety—Related Work Practices
Article 110 of NFPA 70E addresses work practices and procedures that minimize or eliminate completely the exposure to hazards or potential hazards associated with electrical energy. Workers often interact with electrical equipment in a manner that exposes them to potential electrical hazards. The scope of any article in codes and standards sets the foundation for the article and provides clear application parameters. The purpose of Article 110 is to cover both work practices and procedures that provide for employee safety.
Section 110.1 has been revised to meet style manual requirements and addresses words and phrases for consistency with the definitions of defined terms in Article 100. Although the text of the scope was being revised, no changes in scope (coverage) are intended. The scope of this standard remains the same, with the inclusions and the same exclusions.
Section 110.5 covers host and subcontractor relationships. The new language is intended to address these relationships more directly as they relate to adhering to safety-related work practices. The revised language outlines responsibilities of contractors and host employers. For clarification, a host employer may be a general contractor or a facility owner. Although the new language defines responsibilities, it does not relieve either the subcontractor (typically the electrical contractor) or host (typically the general contractor) from requesting information from the other. Each employer (contractor) must tell the other about any unique or specific hazards associated with the project. For instance, the general contractor (host) employer is more likely to be familiar with hazards associated with the site and perhaps the job, while the electrical contractor is more likely to be familiar with necessary safety-related work practices and routine protective measures such as use of lockout/tagout procedures.
Section 110.6(C) requires employees to receive CPR training, as it did in the 2004 edition, but it now requires annual recertification.
Section 110.6(D)(1)(e) is new and requires employees to demonstrate the ability to use voltage-detectors. This revision will result in specific training in voltage-detection equipment selection and use. Testing for the absence of voltage is an essential part of establishing an electrically safe work condition. Many accidents have resulted from inappropriate selection of voltage detection equipment, use of improper equipment settings, and not following safe testing procedures. Employees have to demonstrate competence in voltage detector use, settings and understandings of readings.
Section 110.6(E) now requires employee training to be documented, and employee proficiency must be demonstrated.
Section 110.7 requires the employer to implement and now document an overall electrical safety program that directs activity appropriate for the voltage, energy level and circuit conditions. The change here is to include the documentation requirement. The requirement for documentation provides greater assurances that preplanning is applied to allow for meaningful anticipation of the hazards associated with the task.
Electrical safety is as much an individual responsibility as it is an employer responsibility. Workers need safety training to understand, recognize and avoid hazards. Working on electrical installations that are de-energized is the rule. Working on energized electrical equipment is an exception to the rule and must include documented reasons that show that either the task is infeasible in a de-energized state or de-energization introduces additional hazards.
More revisions to the new NFPA 70E-2009, Standard for Electrical Safety in the Workplace, will be covered in Part 2 of this series.
JOHNSTON, former director of education, codes and standards for IAEI, is NECA’s executive director of standards and safety. He is a member of the IBEW and an active member of the NFPA Electrical Section, Education Section and the UL Electrical Council. Reach him at firstname.lastname@example.org.