Electrical Safety
by Michael A. Cherock, PE, RCDD
Last updated: 06-22-2010
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INTRODUCTION
As an engineer, contractor, manufacturer, or maintenance personnel, and whether one's business is electrical in nature or not, electrical safety is a concern shared by all in the building industry. Approximately 300 deaths occur each year by accidental electrocutions. Over 800 people die annually due to fires caused by electrical faults. Each year, electrical mishaps account for thousands of people sustaining shock injury or burns, and electrical failures cause over 1.3 billion dollars in property damage.
(Courtesy of Tim Matyas)
As building systems become more integrated and the industry further embraces sustainable and environmental concepts into design, the importance of continued building operation is more critical. Besides familiar electrical equipment and systems, newer technologies like renewable energy systems and on-site power generation are increasingly becoming integral parts of many projects. Electrical safety issues related to photovoltaic systems and distributed energy resources, such as fuel cells and microturbines, are evolving and must not be overlooked. Electrical safety is an essential element to any successful building project from conception to day-to-day operation. Understanding the importance of electrical safety, how to recognize the forms that electrical safety can undertake, and providing resources for implementing electrical safety in one's work are all required to institute an electrical safety program.
For full understanding, electrical safety is broken down into three distinct topics of discussion: Perspectives and Responsibilities, Modes of Electrical Safety, and Electrical Safety Resources. Each topic is independent but all three rely on the availability and enforcement of the others for full implementation of safety measures. One without the others results in exposure to the hazardous or potentially hazardous effects of electrical energy and its impact on personnel and equipment.
DESCRIPTION
A. Perspectives and Responsibilities
The proper mind frame is the first step to establishing responsibility to enforce standards of electrical safety. So, perspective determines the impact electrical safety has on one's work. The four perspectives are defined by recognized and accepted roles within the building industry:
A perspective does not imply or indicate an individual's role or title within an organization. Rather, the perspective defines a frame of reference. For example, an electrician installing a junction box outdoors inspects the box for defects that may have occurred during the manufacturing process and verifies that it is intended for outdoor installation. Implementation of an adequate electrical safety program requires an electrician to be aware of not only the installation methods associated with mounting outdoor rated enclosures but also to be aware of the standards that an enclosure must meet in order to be rated for outdoor exposure. The electrician can identify with both the contractor's and manufacturer's perspectives during this "simple and routine" installation. All perspectives must be fully understood to achieve the utmost level of electrical safety in one's work, see Fig. 1.
Fig. 1: Perspective Interrelationships
Engineer's Perspective
The engineer's perspective identifies measures necessary to achieve electrical safety in the engineering design process. Hence, the engineer's perspective evolves into a responsibility that ensures electrical safety from conception of a need to the implementation of an idea. General responsibilities include:
- Equipment ratings
- Conductor ampacities
- Selective coordination of overcurrent protective devices
- Adherence to applicable codes
- Supply/demand equality
- General power distribution methods
The term engineer is not reserved only for the electrical engineer but, instead, includes all disciplines involved in the process of engineering. For example, the mechanical engineer must responsibly contribute needed electrical data for heating, ventilating, and air-conditioning (HVAC) equipment, and controls.
Contractor's Perspective
The contractor's perspective identifies measures necessary for electrical safety in the installation process. Hence, the contractor's perspective evolves into a responsibility that ensures electrical safety from implementation of an idea to complete realization of that idea. General responsibilities include:
- Proper mounting of equipment
- Adequate tightening or torque of connections
- Use of correct tools
- Minimizing of insulation abrasion
- Onsite coordination with other contractors
- Adherence to applicable codes
(Courtesy of Joe Tedesco)
The term contractor is not reserved only for electrical contractor but, instead, includes all trades. For example, the mechanical contractor must responsibly utilize the proper method of installation of the mechanical equipment for interconnection of electrical feeds including elevators, HVAC equipment, and controls.
Maintenance Perspective
The maintenance perspective identifies measures necessary for electrical safety in the operation of a system. This perspective is one that deciphers the preventative, real-time, and reactive actions available to continued system operation. Hence, the maintenance perspective evolves into a responsibility that ensures electrical safety by implementation of preventative programs and ongoing system monitoring. General responsibilities include:
- Preventative maintenance
- Monitoring of equipment parameters
- Use of safety measures when working on equipment
- Following tag out procedures
- Use of correct tools
- Thorough knowledge of systems
- Adherence to applicable codes
Manufacturer's Perspective
The manufacturer's perspective identifies measures necessary for electrical safety in the creation and construction of equipment and devices. Hence, the manufacturer's perspective evolves into a responsibility that ensures electrical safety by implementing the other three perspectives during the respective phases of the manufacturing process. The employment of the other three perspectives and understanding end user utilization must align singularly for the purpose of electrical safety. General responsibilities include:
(Courtesy of Peter L. Jannitto, Jr.)
- Equipment ratings
- Conductor ampacities
- Selective coordination of overcurrent protective devices
- Adherence to applicable codes
- Supply/demand equality
- General power distribution methods
- Proper mounting of equipment
- Adequate tightening or torque of connections
- Use of correct tools
- Preventative maintenance
- Monitoring of equipment parameters
B. Modes of Electrical Safety
Once perspectives and responsibilities are determined, electrical safety is further defined by mode. There are three major modes:
Each mode constitutes a different approach to safety and is defined by the work performed. The three modes combined form an all inclusive approach to maintaining electrical safety as an integral part of any process or program involving electricity, see Fig. 2.
Fig. 2: Mode Interrelations
Preventative Mode
The preventative mode is identified by administrative actions utilized to ward off or prevent electrical mishaps prior to work being performed. A list of actions for the preventative mode should include:
- Implementation of preventative maintenance programs
- Requiring tagout/lockout procedures
- Instituting second-checks requirements for de-energizing during troubleshooting
- Resourcing applicable codes during design
The initial step towards developing an electrical safety program for an individual or agency is to generate a list of administrative actions identified as "preventative" with respect to the nature of their work.
Real-Time Mode
The real-time mode is identified by procedural actions to ward off or prevent electrical mishaps while performing work. In many cases, the real-time mode is the implementation of actions identified in preventative mode. A list of actions for the real time mode should include:
- Preventative maintenance being performed
- Tagout/lockout procedures being completed during system repair
- Second-checks while de-energizing equipment
- Applying code requirements during design
- Correct installation procedure
- Proper tie-offs on equipment supports
- Torque checks
An electrical safety program for an individual or agency should generate a list of procedural actions identified as "real time" with respect to the nature of their work and to coordinate those actions with the preventative mode actions.
Reactive Mode
The reactive mode is identified by procedural and administrative actions utilized to address electrical mishaps that are occurring or have occurred. The reactive mode tends to be the main focus of many established programs and generally garners the most attention by others outside the building industry because of the detrimental effect electrical mishaps can cause. A list of actions for reactive mode should include:
- Fire suppression training
- Electrical shock training (see Fig. 3: Effects of Electric Shock Levels)
- CPR training
- Electrical shock victim identification
- Emergency planning
- Electrical system orientation
Fig. 3: Effects of Electric Shock Levels @ 60Hz*
| Amps | Description |
|---|---|
| 1-15mA | Perception of electrical current. |
| 15-100 mA | Muscles contract and cannot release, severity determined by current level. |
| 100 mA | Ventricular fibrillation of the heart occurs. |
| > 2 Amps | Body receives major burns due to "frying" effect. |
| * Assume worst case body resistance of 300Ohms with varying voltage applied to reach listed currents. Current levels and effects remain approximate due to factors such as health, age, size, etc of the victim. | |
An electrical safety program for an individual or company agency should generate a list of procedural and administrative actions identified as "reactive" with respect to the nature of their work and coordinate those actions with the preventative and real-time modes.
C. Electrical Safety Resources
Resources abound that enable one or one's agency to better recognize perspective and responsibility for electrical safety. With so many resources available, an electrical safety program should implement a method of sourcing the information into a manner that is easily accessible. An "Electrical Safety Library" is a start to organizing and making the vast information easier to access. Equally important is the ability to access different media types. Today, not only is access to the Internet a necessity but multiple entry points are suggested. A dedicated area on the computer network for electrical information is an excellent way to manage and identify resources on hand and those becoming available. Within the database, electrical safety resources should be categorized by Perspectives and Modes. Lastly, all electrical safety resources enforced by local ordinance or codes, or required by one's agency should be noted and made available to all users.
APPLICATION
Electrical safety has been a concern for all since the time electricity became an essential part of everyone's daily lives. However, for those in the building industry, ownership of electrical safety is a necessity. The building industry and all those immediately affected by it often dictate the rules governing one's actions for the benefit of the end user. Therefore, electrical safety requires a proactive approach most often initiated at an organizational level. The perspectives, modes, and resources presented in this Resource Page should be used to establish the framework necessary for one or one's organization to develop or realign an electrical safety program better tailored to meet one's needs. It is important to note that the first step to any effective safety program is structure, followed by education and implementation.
RELEVANT CODES AND STANDARDS
- National Electrical Code (NEC) - NFPA 70—The NEC is the accepted standard for protection of persons and property from electrical installations. Familiarization with NFPA 70 is a must for any one whose responsibility is designing, installing, verifying and maintaining safe and compliant electrical systems. Information can be found through the NFPA website with a membership or printed and electronic versions of the code can be purchased from NFPA and other suppliers.
- National Electrical Installation Standards—The NEIS gives definition to "neat and workmanlike manner" as required by the National Electrical Code. Each standard is submitted for approval by the American National Standards Institute (ANSI).
- National Electrical Safety Code (NESC)—The NESC is a product of the Institute of Electrical and Electronics Engineers (IEEE). This code provides information on the installation, operation, and maintenance of electrical systems. The intent of the publication is the safeguarding of persons performing the work. Information, like the NEC, is available with IEEE membership or by buying a printed or electronic version of the code.
- National Fire Protection Association (NFPA)—The NFPA is the definitive source for everything related to fire protection. The association has developed numerous standards that have been adopted by federal, state, and local jurisdictions as enforceable standards. The site has plenty of free information but more specific information is restricted to members only.
- National Institute for Occupational Safety and Health (NIOSH)—NIOSH is similar in mission to OSHA but differs by the singular perspective that NIOSH is the federal agency responsible for the prevention of work related disease and injury, and is part of the Centers for Disease Control and Prevention.
- Occupational Health and Safety Administration (OSHA)—OSHA is the main governmental source for effective safety practices. The website is a vast, readily accessible information resource with a thorough search engine.
ADDITIONAL RESOURCES
WBDG
Design Objectives
Productive—Promote Health & Well-Being, Secure/Safe—Plan for Fire Protection, Secure / Safe—Ensure Occupant Safety and Health
Products and Systems
Federal Green Construction Guide for Specifiers:
- 11 13 00 (11160) Loading Dock Equipment
- 11 28 00 (11680) Office Equipment
- 11 30 00 (11450) Residential Equipment
- 23 70 00 (15700) Central HVAC Equipment
- 26 50 00 (16500) Lighting
- 48 14 00 (13600) Solar Energy Electrical Power Generation Equipment
- 48 15 00 (13600) Wind Energy Electrical Power Generation Equipment
- 48 30 00 (13600) Biomass Energy Electrical Power Generation Equipment
Organizations/Associations
- Electrical Safety Foundation International (ESFI)
- National Electrical Contractors Association (NECA)
- National Electrical Manufacturers Association (NEMA)
- National Safety Council (NSC)
- National Society of Professional Engineers (NSPE)
Others
- Bureau of Labor Statistics
- Electrical Construction and Maintenance
- Ground-Fault Protection on Construction Sites
- National Institute of Standards and Technology (NIST)
- SAFTENG.net
- Underwriter's Laboratories Inc. (UL)
http://www.wbdg.org/resources/electricalsafety.php
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