Electrical Terms Glossary

For your convenience, e-Hazard has put together a list of terms commonly used in relation to the electrical industry and electrical and arc flash safety.

Arc flash is the passage of current through air between phase conductors or phase conductors and neutral and ground. This is initiated by a flashover, or from the introduction of some conductive material. Temperatures from an arc flash can reach 35,000 degrees Fahrenheit. Exposure to an arc flash can severely burn skin and ignite clothing.

Also See: What is Arc Flash?

An arc flash audit is an analysis of arc flash hazard and risk, focusing on compliance to all standards, including NFPA 70E, OSHA, and NESC. The audit uncovers areas of noncompliance and includes recommendations for improvements in order to meet the required standards.

Visit our Services page to view our arc flash audit options.

Engineering calculations, or modeling, determine the arc flash protection boundary and the incident energy level exposure to workers, as part of an arc flash hazard assessment. The generally accepted method of calculation is a nine-step process outlined in the IEEE 1584 Guide for Performing Arc-Flash Hazard Calculations. This is a complicated procedure depending upon accurate data collection, and therefore should be done only by highly trained and qualified personnel.

View our arc flash calculations related classes on our Arc Flash Engineering page.

An arc flash study (also called an arc flash hazard assessment or an arc flash hazard analysis) is a study investigating a worker’s potential exposure to arc flash energy, conducted for the purpose of injury prevention, the determination of safe work practices and arc flash boundary, and the appropriate levels of personal protective equipment (PPE).

e-Hazard arc flash studies are conducted on-site by a trained expert qualified to evaluate the electrical system of a facility and notate areas potentially presenting a risk to personnel or equipment. The study report offers recommendations of appropriate PPE and suggests ways to reduce workers’ exposure to arc flash hazards.

Also See: Arc Flash Studies & Analysis Options

Amount of energy required to raise the temperature of one gram of water one Celsius degree.

Example: If you take a disposable lighter and put your palm in the hottest part of the flame for one second, you will receive about 1.2 calories per cm2 – the onset of a second degree burn (blister burn)

Electrical safety is the practice of recognizing and taking the action steps necessary for being in the presence of electrical energy. Electrical safety involves taking precautions in order for hazards not to cause injury or death. According to NFPA 70E, employers must implement and document an overall electrical safety program, directing activity appropriate for the electrical hazards, voltage, energy level, and circuit conditions.

An on-site examination, customized to a workplace facility, in order to verify the principles and procedures of an electrical safety program are being adhered to and are in compliance with NFPA 70E/CSA Z462 and OSHA1910/1926 standards. If the ESP is not being followed, revisions to the training program or procedures must be made. Areas investigated include PPE, Arc Flash Equipment Labeling and Equipment Specific Lockout/Tagout Program Writing.

Energized work refers to work being done on “live” parts, also known as a source of voltage, potentially exposing the worker to any hazard they present.

A flashover is an electric discharge over or around the surface of an insulator. This happens when the ignition of smoke or fumes from surrounding objects causes the unexpected and rapid spread of fire through the air.

A hazard/risk assessment is completed at a workplace facility in order to estimate the risk of potential electrical hazards and determine the protective measures needed to reduce the level of risk. The process of an hazard/risk assessment includes a process of identifying and analyzing electrical hazards before work is started within the limited approach boundary or within the arc flash boundary of energized electrical conductors and circuit parts operating at 50 volts or more, or where an electrical hazard exists.

According to the NEC (National Electrical Code), high voltage is any voltage over 600V, and this is the cutoff used by e-Hazard for training purposes. There are differences of opinion, however; the IEEE (Institute of Electrical and Electronics Engineers) considers over 1000V to be high voltage for alternating current (AC) and at least 1500 V as high voltage for direct current (DV).

A person who is high voltage qualified has skills and knowledge related to the construction and operation of electrical equipment and installations with any voltage over 600V. A HV Qualified professional will have received high voltage safety training to recognize and avoid the hazards involved.

Checkout our High Voltage Training classes.

Lockout-tagout (LOTO) refers to “deenergizing lines and equipment for employee protection,” according to OSHA regulations. It relates to the servicing and maintenance of machines and equipment in which the unexpected start-up or the release of stored energy could cause injury to employees. For example, hazards can be controlled by unplugging the equipment from the energy source when servicing, or cutting off the electricity by utilizing locks and tags. The locks keep the lines for electricity incapable of being restored, while the tags alert people not to turn on the energy source for the machines currently in service.

According to the NEC (National Electrical Code), refers to voltage with less than 600 volts of electricity (see High Voltage definition above).

A person who is low voltage qualified has skills and knowledge related to the construction and operation of electrical equipment and installations with less than 600 volts of electricity. This professional will have received low voltage safety training to recognize and avoid the hazards involved.

Take a look at our Low Voltage Electrical Safety Training classes.

The National Electrical Code (NEC), published by the National Fire Protection Association (NFPA), is the benchmark of safe electrical design, installation and inspection to protect people and property from electrical hazards. It addresses the installation of conductors, equipment and raceways in the electrical and communications industries and optical fiber cables and raceways. Adopted in all 50 states, it addresses requirements for construction, whereas the NFPA 70E focuses on employee protection.

Published by the IEEE (Institute of Electrical and Electronics Engineers) the National Electrical Safety Code (NESC) sets the ground rules for the practical safeguarding of persons during the installation, operation or maintenance of electric supply and communication lines and associated equipment. It contains the basic provisions considered necessary for the safety of employees and the public under the specified conditions.

The NFPA 70E is the National Fire Protection Association’s published Standard for Electrical Safety in the Workplace. The Standard is updated every three years. The NFPA 70E requires employers to assess hazards and work practices; have site-specific written programs; select appropriate personal protective equipment; provide electrical safety training for employees; perform regular inspections and audits; and maintain proper records.

Also See: NFPA 70E Training

Unqualified workers who operate equipment or machinery and have become task qualified for a specific electrical task.

Also See: Task Qualified Switch Operator

The Occupational Health and Safety Administration (OSHA) is a federal agency operating under the U.S. Department of Labor. The mission of OSHA is to ensure businesses provide safe and healthy working environments for all their employees. OSHA creates standards for health and safety in the workplace, and investigates businesses to enforce compliance with OSHA regulations.

OSHA Specifics

OSHA 269

OSHA 269 refers to Part 1910.269 of the government’s Code of Federal Regulations (CFR). This part of the code establishes occupational safety and health standards for employees working in industries relating to electric power generation, transmission and distribution.

OSHA 300 Series

The OSHA 300 Series refers to a set of forms on which employers must record all work-related injuries and illnesses to conform to OSHA mandates. The 300 Series System includes the required forms and provides guidance on proper completion and record-keeping to meet OSHA requirements.

Personalized Protective Equipment or PPE is specialized clothing or equipment worn by employees for protection against health and safety hazards. Personal protective equipment is designed to protect many parts of the body, including the eyes, head, face, hands, feet and ears. Examples of PPE include such items as gloves, ear plugs or muffs, hard hats, respirators and full body suits.