osha definitions

OSHA Definitions, Glossary & Commonly Used Terms

osha definitionsOSHA Definitions are often times an interpretation of a word or phrase, instead of how Webster Dictionary may define it. OSHA Stands for the Occupational Safety and Health Administration of the United States Department of Labor, formed by the Occupational Safety and Health Act of 1970. CSHO is an abbreviation for an OSHA Compliance Safety and Health Officer or Compliance Officer.




Accepted, Electrical: An installation is “accepted” if it has been inspected and found to be safe by a qualified testing laboratory.

Accepted engineering practices: stems from the selection and application of appropriate engineering, operating, and maintenance knowledge when designing, operating and maintaining chemical facilities with the purpose of ensuring safety and preventing process safety incidents.

Accessible. (As applied to wiring methods.) Capable of being removed or exposed without damaging the building structure or finish, or not permanently closed in by the structure or finish of the building. (See “concealed” and “exposed.”)

Accessible. (As applied to equipment.) Admitting close approach; not guarded by locked doors, elevation, or other effective means. (See “Readily accessible.”)

Act of Violence – An act of violence is the attempt (coupled with the ability), or actual use of force of violence with the intent to threaten, harass, intimidate, commit a violent injury, or damage/destroy property. See also, workplace violence

Adjusted suspension scaffold: A suspension scaffold equipped with a hoist that can be operated by an employee on the scaffold. A single-point adjustable scaffold consists of a platform suspended by one rope from an overhead support and equipped with means to permit the movement of the platform to desired work levels. The most common among these is the scaffold used by window washers to clean the outside of a skyscraper (also known as a boatswain’s chair).

Affected Personnel: Personnel who normally use and work with electrical equipment, tools, and appliances, but who do not make repairs or perform lock out/tag out procedures. Affected employees must receive training on the purpose and use of the energy control procedure.

Alternative work: A new job with your former employer. If your doctor says you will not be able to return to your job at the time of injury, your employer is encouraged to offer you alternative work instead of supplemental job displacement benefits or vocational rehabilitation benefits. The alternative work must meet your work restrictions, last at least 12 months, pay at least 85 percent of the wages and benefits you were paid at the time you were injured, and be within a reasonable commuting distance of where you lived at the time of injury.

Aluminum Hydraulic Shoring: a pre-engineered shoring system comprised of aluminum hydraulic cylinders (crossbraces) used in conjunction with vertical rails (uprights) or horizontal rails (wales). Such system is designed specifically to support the sidewalls of an excavation and prevent cave-ins.

Ampacity: The current in amperes a conductor can carry continuously under the conditions of use without exceeding its temperature rating.

Anchorage means a secure point of attachment for lifelines, lanyards or deceleration devices.

Anchorage: A secure point of attachment for lifelines, lanyards, or deceleration devices.

Appliances: Utilization equipment, generally other than industrial, normally built in standardized sizes or types, which is installed or connected as a unit to perform one or more functions.

Approved: indicates what is acceptable to the Assistant Secretary of Labor, and therefore approved within the meaning of the particular Subpart.

Arc Fault Current: For Arc Flash Hazard Analysis calculations, use the short circuit symmetrical amperes from a bolted 3-phase fault. Select the value at time of circuit interruption.

Arc Flash Hazard Analysis: Calculations to predict the Arc thermal energy from the source of an electric arc fault.

Arc Flash Hazard Assessment: A process to determine if an Arc Flash Hazard exists.

Arc Flash Hazard: Danger due to Arc thermal energy from an electric arc fault.

Arc In A Box: The estimated Arc Thermal Energy created in a six-sided metal enclosure. The Arc Flash Hazard is present due to one side open.

Arc Thermal Energy: Radiant heat intensity in calories/cm2 emitted by an electrical arc.

Arc Thermal Performance Value (ATPV): Amount of heat energy in cal/cm2 a fabric or garment is rated to protect the wearer from a second-degree burn. (Note: The onset of a second-degree bum to the skin is 1.2 calories/cm2.)

Asbestos is a silicate mineral, a fibrous, Naturally Occurring material of varying chemical compositions.  Asbestos is used in well over 3,000 products including building materials and goods.

Askarel: A generic term for a group of nonflammable synthetic chlorinated hydrocarbons used as electrical insulating media. Askarels of various compositional types are used. Under arcing conditions the gases produced, while consisting predominantly of noncombustible hydrogen chloride, can include varying amounts of combustible gases depending upon the askarel type.

Attachment plug (Plug cap)(Cap): A device which, by insertion in a receptacle, establishes connection between the conductors of the attached flexible cord and the conductors connected permanently to the receptacle.

Audiometric testing – means detection by the person being tested of a series of pure tones. For each tone, the person indicates the lowest level of intensity that they are able to perceive.

Authorized employee: An employee who locks or tags machines or equipment in order to perform servicing or maintenance.

Authorized Person Unit: AA person approved or assigned by the employer to perform a specific type of duty or duties or to be at a specific location or locations at the jobsite.

Automatic. Self-acting, operating by its own mechanism when actuated by some impersonal influence, as for example, a change in current strength, pressure, temperature, or mechanical configuration.


Bearer – A horizontal member of a scaffold upon which the platform rests and which may be supported by ledgers.

Bell-bottom pier hole: a type of shaft or footing excavation, the bottom of which is made larger than the cross section above to form a belled shape.

Benching (Benching system) is a method of protecting employees from cave-ins by excavating the sides of an excavation to form one or more horizontal steps, usually with vertical or near-vertical surfaces between levels.

Body belt (safety belt) means a strap with means both for securing it about the waist and for attaching it to a lanyard, lifeline, or deceleration device.

Body belt: A strap with means both for securing it about the waist and for attaching it to a lanyard, lifeline, or deceleration device.

Body harness means straps which may be secured about the employee in a manner that will distribute the fall arrest forces over at least the thighs, pelvis, waist, chest and shoulders with means for attaching it to other components of a personal fall arrest system.

Body harness: Straps which may be secured about the employee in a manner that will distribute the fall arrest forces over at least the thighs, pelvis, waist, chest, and shoulders, with means for attaching it to other components of a personal fall arrest system.

Bonding: The permanent joining of metallic parts to form an electrically conductive path which will assure electrical continuity and the capacity to conduct safely any current likely to be imposed.

Bonding jumper: A reliable conductor to assure the required electrical conductivity between metal parts required to be electrically connected.

Brace: A rigid connection that holds one scaffold member in a fixed position with respect to another member, or to a building or structure.

Branch circuit: The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).

Building: A structure which stands alone or which is cut off from adjoining structures by fire walls with all openings therein protected by approved fire doors.

Buckle: any device for holding the body belt or body harness closed around the employee’s body.


Cabinet: An enclosure designed either for surface or flush mounting, and provided with a frame, mat, or trim in which a swinging door or doors are or may be hung.

Cave-in: the movement of soil or rock into an excavation, or the loss of soil from under a trench shield or support system, in amounts large enough to trap, bury, or injure and immobilize a person.

Certified: Equipment is “certified” if it (a) has been tested and found by a nationally recognized testing laboratory to meet nationally recognized standards or to be safe for use in a specified manner; or (b) is of a kind whose production is periodically inspected by a nationally recognized testing laboratory; and (c) it bears a label, tag, or other record of certification.

Circuit Breaker: (a) (600 volts nominal, or less.) A device designed to open and close a circuit by nonautomatic means and to open the circuit automatically on a predetermined overcurrent without injury to itself when properly applied within its rating. (b) (Over 600 volts, nominal.) A switching device capable of making, carrying, and breaking currents under normal circuit conditions, and also making, carrying for a specified time, and breaking currents under specified abnormal circuit conditions, such as those of short circuit.

Cleat – A ladder crosspiece of rectangular cross section placed on edge upon which a person may step while ascending or descending a ladder.

Close Proximity: Close enough to reach, fall into, or otherwise accidentally contact an electrical source. Working in Close Proximity would be within the Electrical Arc Flash Hazard Boundary.

Combustible Dust (NEP): A combustible particulate solid that presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations, regardless of particle size or shape.

Competent Person: one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.

Competent person: One who is capable of identifying existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.  There is no specific class, degree or years of experience that can make someone a competent person. However, training can assist in the task. The company typically designates a job foreman, supervisor or superintendent as a competent person. Upper management relies upon this individual to address hazards and train others in safety and health issues.


(a) Bare. A conductor having no covering or electrical insulation whatsoever.

(b) Covered. A conductor encased within material of composition or thickness that is not recognized as electrical insulation.

(c) Insulated. A conductor encased within material of composition and thickness that is recognized as electrical insulation.

Confined Space: A space defined by the concurrent existence of the following conditions:

  • Existing ventilation is insufficient to remove dangerous air contamination and/or oxygen deficiency, which may exist or
  • Ready access or egress for the removal of a suddenly disabled employee is difficult due to the location and/or size of the opening.

Connector means a device which is used to couple (connect) parts of the personal fall arrest system and positioning device systems together. It may be an independent component of the system, such as a carabineer, or it may be an integral component of part of the system (such as a buckle or D-ring sewn into a body belt or body harness, or a snap-hook spliced or sewn to a lanyard or self-retracting lanyard).

Coupler – A device for locking together the components of a tubular metal scaffold which shall be designed and used to safely support the maximum intended loads.

Cross braces mean the horizontal members of a shoring system installed from side to side of the excavation. The cross braces bear against either uprights or Wales.

Crystalline Silica: Crystalline silica is a basic component of soil, sand, granite, and many other minerals. Quartz is the most common form of crystalline silica. Cristobalite and tridymite are two other forms of crystalline silica. All three forms may become respirable size particles when workers chip, cut, drill, or grind objects that contain crystalline silica

Cumulative injury (CT): An injury that was caused by repeated events or repeated exposures at work. For example, hurting your wrist doing the same motion over and over or losing your hearing because of constant loud noise.

Cutout: (Over 600 volts, nominal.) An assembly of a fuse support with either a fuseholder, fuse carrier, or disconnecting blade. The fuseholder or fuse carrier may include a conducting element (fuse link), or may act as the disconnecting blade by the inclusion of a nonfusible member.

Cutout box: An enclosure designed for surface mounting and having swinging doors or covers secured directly to and telescoping with the walls of the box proper. (See “Cabinet.”)


Date of injury: When you got hurt or ill. If your injury was caused by one event, the date it happened is the date of injury. If the injury or illness was caused by repeated exposures (a cumulative injury), the date of injury is the date you knew or should have known the injury was caused by work.

Dead front: Without live parts exposed to a person on the operating side of the equipment.

Deceleration device means any mechanism, such as a rope grab, rip-stitch lanyard, specially-woven lanyard, tearing or deforming lanyards, automatic self-retracting lifelines/lanyards, etc., which serves to dissipate a substantial amount of energy during a fall arrest, or otherwise limit the energy imposed on an employee during fall arrest.

Deceleration distance means the additional vertical distance a falling employee travels, excluding lifeline elongation and free fall distance, before stopping, from the point at which the deceleration device begins to operate. It is measured as the distance between the location of an employee’s body belt or body harness attachment point at the moment of activation (at the onset of fall arrest forces) of the deceleration device during a fall, and the location of that attachment point after the employee comes to a full stop.

Decibels – means the sound energy measured by a sound level meter using the “A” scale.  The “A” scale is electronically weighted to simulate the response of the human ear to high and low frequency noise.

Defect: Any characteristic or condition which tends to weaken or reduce the strength of the tool, object, or structure of which it is a part.

Description of employee’s job duties (RU-91): A form filled out jointly by you and the insurance company that helps your treating physician decide whether you will be able to return to your normal job and working conditions.

Device. A unit of an electrical system which is intended to carry but not utilize electric energy.

Disability: A physical or mental impairment that limits your life activities. A condition that makes engaging in physical, social and work activities difficult.

Discipline: in the dictionary is Instruction. Another definition is Training that corrects, molds, and perfects.

Disconnecting Means: A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply.

Disconnecting (or Isolating) switch: (Over 600 volts, nominal.) A mechanical switching device used for isolating a circuit or equipment from a source of power.

Double Insulated Tool: Tools designed of non-conductive materials that do not require a grounded, three wire plug.

Double pole or independent pole scaffold – A scaffold supported from the base by a double row of uprights, independent of support from the walls and constructed of uprights, ledgers, horizontal platform bearers, and diagonal bracing.

Double-Cleat Ladder – A ladder with a center rail to allow simultaneous two-way traffic for employees ascending or descending.

Dust: solid particles generated by handling, crushing, grinding, rapid impact, detonation, and decrepitation of organic or inorganic materials, such as rock, ore, metal, coal, wood, and grain


Electrical Arc Flash Hazard Boundary: The distance from an arc flash hazard source where Arc Thermal Energy applied to the skin is equal to 1.2 calories/cm2 which are the onset of a second-degree burn to the skin. Additional PPE is required within this area for protection from arc thermal energy.

Employee: A person whose work activities are under the control of an individual or entity. The term employee includes undocumented workers and minors. Every laborer or mechanic, regardless of the contractual relationship which may be alleged to exist between the laborer and mechanic and the contractor or subcontractor who engaged him. “Laborer” generally means one who performs manual labor or who labors at an occupation requiring physical strength; “mechanic” generally means a worker skilled with tools.

Employer: The person or entity with control over your work activities.

Energized: Machines and equipment are energized when they are connected to an energy source or they contain residual or stored energy.

Energy-isolating device: A mechanical device that physically prevents the transmission or release of energy, including but not limited to the following: A manually operated electrical circuit breaker; a disconnect switch; a manually operated switch by which the conductors of a circuit can be disconnected from all ungrounded supply conductors and, in addition, no pole can be operated independently; a line valve; a block; and any similar device used to block or isolate energy. Push buttons, selector switches and other control circuit type devices are not energy isolating devices.

Energy of Break Open Threshold (EBT): Amount of heat energy in calories/cm2 a fabric or garment is rated before the garment fabric breaks open. EBT is averaged from the highest five energy values.

Energy source: Any source of electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other energy.

Environmental risk factors for heat illness means working conditions that create the possibility that heat illness could occur, including air temperature, relative humidity, radiant heat from the sun and other sources, conductive heat sources such as the ground, air movement, workload severity and duration, protective clothing and personal protective equipment worn by employees.

Equipment, Electrical: A general term including material, fittings, devices, appliances, fixtures, apparatus, and the like, used as a part of, or in connection with, an electrical installation.

Equivalent means alternative designs, materials, or methods to protect against a hazard which the employer can demonstrate will provide an equal or greater degree of safety for employees than the methods, materials or designs specified in the standard.

Ergonomics: The study of how to improve the fit between the physical demands of the workplace and the employees who perform the work. That means considering the variability in human capabilities when selecting, designing or modifying equipment, tools, work tasks and the work environment.

Essential functions: Duties considered crucial to the job you want or have. When being considered for alternative work, you must have both the physical and mental qualifications to fulfill the job’s essential functions.

Excavation means any man-made cut, cavity, trench, or depression in an earth surface formed by earth removal.

Explosion-proof apparatus: Apparatus enclosed in a case that is capable of withstanding an explosion of a specified gas or vapor which may occur within it and of preventing the ignition of a specified gas or vapor surrounding the enclosure by sparks, flashes, or explosion of the gas or vapor within, and which operates at such an external temperature that it will not ignite a surrounding flammable atmosphere.

Exposed. (As applied to wiring methods.) On or attached to the surface or behind panels designed to allow access. [See “Accessible. (As applied to wiring methods.)”]

Exposed. (For the purposes of § 1926.408(d), Communications systems.) Where the circuit is in such a position that in case of failure of supports or insulation, contact with another circuit may result.

Extension trestle ladder: An extension trestle ladder is a self-supporting portable ladder, adjustable in length, consisting of a trestle ladder base and a vertically adjustable single ladder, with suitable means for locking the ladders together. The size is designated by the length of the trestle ladder base.

Externally operable. Capable of being operated without exposing the operator to contact with live parts.


Faces or sides: the vertical or inclined earth surfaces formed as a result of excavation work.

Failure: Load refusal, breakage, or separation of components.

Failure: load refusal, breakage, or separation of component parts. Load refusal is the point where the ultimate strength is exceeded.

Failure: the movement or damage of a structural member or connection that makes it unable to support loads.

Feeder: All circuit conductors between the service equipment, or the generator switchboard of an isolated plant, and the final branch-circuit overcurrent device.

Festoon lighting: A string of outdoor lights suspended between two points more than 15 feet (4.57 m) apart.

Fitting: An accessory such as a locknut, bushing, or other part of a wiring system that is intended primarily to perform a mechanical rather than an electrical function.

First Aid: injury is one which only minor injuries occur and which can normally be handled by a trained first aid person. This also includes initial treatment and a one-time follow-up visit even if treated by a physician. However, once prescription medication is provided or stitches are required, the injury is then required to be classified as a recordable injury per OSHA.

Fixed Ladder: A ladder that cannot be readily moved or carried because it is an integral part of a building or structure.

Flame Resistant (FR): Material treated with a chemical flame retardant to prevent clothing ignition, or natural materials that are inherently flame resistant (e.g. wool, PR 97, Nomex).

Floor opening: An opening measuring 12 inches or more in its least dimension, in any floor, platform, pavement, or yard through which persons may fall; such as a hatchway, stair or ladder opening, pit, or large manhole. Floor openings occupied by elevators, dumb waiters, conveyors, machinery, or containers are excluded from this subpart.

Forklift (Powered Industrial Truck): Any mechanical device used for the movement of supplies, material or finished a product that is powered by an electric motor or an internal combustion engine.

Free fall distance: the vertical displacement of the fall arrest attachment point on the employee’s body belt or body harness between onset of the fall and just before the system begins to apply force to arrest the fall. This distance excludes deceleration distance, and lifeline/lanyard elongation, but includes any deceleration device slide distance or self-retracting lifeline/lanyard extension before they operate and fall arrest forces occur.

Free fall: the act of falling before a personal fall arrest system begins to apply force to arrest the fall.

Fuse: (Over 600 volts, nominal.) An overcurrent protective device with a circuit opening fusible part that is heated and severed by the passage of overcurrent through it. A fuse comprises all the parts that form a unit capable of performing the prescribed functions. It may or may not be the complete device necessary to connect it into an electrical circuit.


Ground Fault Circuit Interrupter (GFCI): A device whose function is to interrupt the electric circuit to the load when a fault current to ground exceeds some predetermined value that is less than that required to operate the over current protective device of the supply circuit.

Ground: Connected to earth or some conducting body that serves in place of the earth.

Grounded Conductor: A conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes.

Guardrail – A rail secured to uprights and erected along the exposed sides and ends of platforms.

Guardrail system means a barrier erected to prevent employees from falling to lower levels.


Handrail: A rail used to provide employees with a handhold for support.

Harassment: The creation of a hostile work environment through unwelcome words, actions, or physical contact not resulting in physical harm. Verbal harassment may include disparaging or derogatory comments or slurs, unreasonable or excessive criticism, or name calling.

Hazardous atmosphere: an atmosphere that is explosive, flammable, poisonous, corrosive, oxidizing, irritating, oxygen deficient, toxic, or otherwise harmful, which may cause death, illness, or injury.

Hazardous substance (HCO): A substance which, by reason of being explosive, flammable, poisonous, corrosive, oxidizing, irritating, or otherwise harmful, is likely to cause death or injury.

Health care organization (HCO): An organization certified by the Department of Industrial Relations to provide managed medical care within the workers’ compensation system.

Health Safety Officer means the individual at Your Company Name responsible for developing and implementing this program, conducting unannounced work site inspections, and ensuring that the departments comply with the program requirements.

Hearings: Legal proceedings in which a workers’ compensation judge discusses the issues in a case or receives information in order to make a decision about a dispute or a proposed settlement.

Heat Acclimatization: a broad term that can be loosely defined as a complex series of changes or adaptations that occur in response to heat stress in a controlled environment over the course of 7 to 14 days. These adaptations are beneficial to exercise in the heat and allow the body to better cope with heat stress.

Heat Exhaustion: see heat illness

Heat Illness means a serious medical condition resulting from the body’s inability to cope with a particular heat load. Your body normally cools itself by sweating. During hot weather, especially with high humidity, sweating just isn’t enough. Your body temperature can rise to dangerous levels and you can develop a heat illness.

Heavy Duty Scaffold – A scaffold designed and constructed to carry a working load not to exceed 75 pounds per square foot.


Identified (conductors or terminals). Identified, as used in reference to a conductor or its terminal, means that such conductor or terminal can be recognized as grounded.

Identified (for the use). Recognized as suitable for the specific purpose, function, use, environment, application, etc. where described as a requirement in this standard. Suitability of equipment for a specific purpose, environment, or application is determined by a qualified testing laboratory where such identification includes labeling or listing.

IIPP/Injury and Illness Prevention Program: A health and safety program employers are required to develop and implement. This program is enforced by Cal/OSHA.

In pro per: An injured worker not represented by an attorney.

Industrial Injury: An injury arising out of and during the course of employment.

Infeasible: that it is impossible to perform the inspection work using a conventional fall protection system (i.e., guardrail system, safety net system, or personal fall arrest system) or that it is technologically impossible to use any one of these systems to provide fall protection.

Insulated: A conductor encased within material of composition and thickness that is recognized as electrical insulation.

Interrupter switch: (Over 600 volts, nominal.) A switch capable of making, carrying, and interrupting specified currents.

Intimidate: To make afraid; to frighten, alarm, annoy, or scare. To force a person into, or deter them from, some action by inducing fear by, or as if by, threats.

Intrinsically safe equipment and associated wiring: Equipment and associated wiring in which any spark or thermal effect, produced either normally or in specified fault conditions, is incapable, under certain prescribed test conditions, of causing ignition of a mixture of flammable or combustible material in air in its most easily ignitable concentration.

Isolated: Not readily accessible to persons unless special means for access are used.

Isolated power system: A system comprising an isolating transformer or its equivalent, a line isolation monitor, and its ungrounded circuit conductors.


Job-Made Ladder: ladder that is fabricated by employees, typically at the construction site; non-commercially manufactured.


Kickout means the accidental movement or failure of a cross brace.


Labeled. Equipment or materials to which has been attached a label, symbol or other identifying mark of a qualified testing laboratory which indicates compliance with appropriate standards or performance in a specified manner.

Landscaping means providing landscape care and maintenance services and/or installing trees, shrubs, plants, lawns, or gardens, or providing these services in conjunction with the design of landscape plans and/or the construction (i.e., installation) of walkways, retaining walls, decks, fences, ponds, and similar structures, except for employment by an employer who operates a fixed establishment where the work is to be performed and where drinking water is plumbed.

Lanyard means a flexible line of rope, wire rope, or strap which generally has a connector at each end for connecting the body belt or body harness to a deceleration device, lifeline, or anchorage.

Leading edge means the edge of a floor, roof, or formwork for a floor or other walking/working surface (such as the deck) which changes location as additional floor, roof, decking, or formwork sections are placed, formed, or constructed. A leading edge is considered to be an unprotected side and edge during periods when it is not actively and continuously under construction.

Ledger (stringer) – A horizontal scaffold member which extends from post to post and which supports the putlogs or bearer forming a tie between the posts.

Legal drug: means any drug; (a) which is not legally obtained, or (b) which is legally obtainable but has not been legally obtained.  The term includes prescribed drugs not legally obtained and prescribed drugs not being used for prescribed purposes.  It also includes marijuana.

Lifeline means a component consisting of a flexible line for connection to an anchorage at one end to hang vertically (vertical lifeline), or for connection to anchorages at both ends to stretch horizontally (horizontal lifeline), and which serves as a means for connecting other components of a personal fall arrest system to the anchorage.

Light Duty Scaffold – A scaffold designed and constructed to carry a working load not to exceed 25 pounds per square foot.

Lighting outlet: An outlet intended for the direct connection of a lampholder, a lighting fixture, or a pendant cord terminating in a lampholder.

Listed: Equipment or materials included in a list published by a qualified testing laboratory whose listing states either that the equipment or material meets appropriate standards or has been tested and found suitable for use in a specified manner.

Live Line Tools: Tools electrically rated for the voltage involved and used to touch or come in close proximity to exposed, energized conductors or equipment.

Load Refusal: The point where the structural members lose their ability to carry the load.


(a) Damp location. Partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements.

(b) Dry location. A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction.

(c) Wet location. Installations underground or in concrete slabs or masonry in direct contact with the earth, and locations subject to saturation with water or other liquids, such as locations exposed to weather and unprotected.

Lockout: The placement of a lockout device on an energy-isolating device, in accordance with an established procedure, ensuring that the energy-isolating device and the equipment being controlled cannot be operated until the lockout device is removed.

Lockout device: Any device that uses positive means, such as a lock, blank flanges and bolted slip blinds, to hold an energy-isolating device in a safe position, thereby preventing the energizing of machinery or equipment.

Lower levels means those areas or surfaces to which an employee can fall. Such areas or surfaces include, but are not limited to, ground levels, floors, platforms, ramps, runways, excavations, pits, tanks, material, water, equipment, structures, or portions thereof.


Manually Propelled Mobile Scaffold – Manually propelled mobile scaffold.

Maximum intended load: The total of all loads including the working load, the weight of the scaffold, and such other loads as may be reasonably anticipated.

Medium duty scaffold: A scaffold designed and constructed to carry a working load not to exceed 50 pounds per square foot.

Mid-Rail: A rail approximately midway between the guardrail and platform, used when required, and secured to the uprights erected along the exposed sides and ends of platforms.

Mobile X-ray: X-ray equipment mounted on a permanent base with wheels and/or casters for moving while completely assembled.

Motor control center: An assembly of one or more enclosed sections having a common power bus and principally containing motor control units.


Normal production operations: Utilization of a machine or equipment to perform its intended production function.


Oil and gas extraction means operating and/or developing oil and gas field properties, exploring for crude petroleum or natural gas, mining or extracting of oil or gas or recovering liquid hydrocarbons from oil or gas field gases.

Other employees: All employees who are or may be in an area where energy control procedures may be utilized.

Outlet: A point on the wiring system at which current is taken to supply utilization equipment.

Overcurrent: Any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload (see definition), short circuit, or ground fault. A current in excess of rating may be accommodated by certain equipment and conductors for a given set of conditions. Hence the rules for overcurrent protection are specific for particular situations.

Overload: Operation of equipment in excess of normal, full load rating, or of a conductor in excess of rated ampacity which, when it persists for a sufficient length of time, would cause damage or dangerous overheating. A fault, such as a short circuit or ground fault, is not an overload. (See “Overcurrent.”)


Panelboard: A single panel or group of panel units designed for assembly in the form of a single panel; including buses, automatic overcurrent devices, and with or without switches for the control of light, heat, or power circuits; designed to be placed in a cabinet or cutout box placed in or against a wall or partition and accessible only from the front. (See “Switchboard.”)

Personal fall arrest system: a system used to arrest an employee in a fall from a working level. It consists of an anchorage, connectors, a body belt or body harness and may include a lanyard, deceleration device, lifeline, or suitable combinations of these.

Personal Protective Equipment:Personal protective equipment, commonly referred to as “PPE”, is equipment worn to minimize exposure to hazards that cause serious workplace injuries and illnesses. These injuries and illnesses may result from contact with chemical, radiological, physical, electrical, mechanical, or other workplace hazards. Personal protective equipment may include items such as gloves, safety glasses and shoes, earplugs or muffs, hard hats, respirators, or coveralls, vests and full body suits.

Personal risk factors for heat illness: factors such as an individual’s age, degree of acclimatization, health, water consumption, alcohol consumption, caffeine consumption, and use of prescription medications that affect the body’s water retention or other physiological responses to heat.

Platform: A working space for persons, elevated above the surrounding floor or ground; such as a balcony or platform for the operation of machinery and equipment.

Point of Access: All areas used by employees for work-related passage from one area or level to another.

Portable Ladder: A ladder that can be readily moved or carried.

Positioning device system means a body belt or body harness system rigged to allow an employee to be supported on an elevated vertical surface, such as a wall, and work with both hands free while leaning.

Power fuse: (Over 600 volts, nominal.) See “Fuse.”

Power outlet: An enclosed assembly which may include receptacles, circuit breakers, fuseholders, fused switches, buses and watt-hour meter mounting means; intended to serve as a means for distributing power required to operate mobile or temporarily installed equipment.

Premises Wiring: That interior and exterior wiring, including power, lighting, control, and signal circuit wiring together with all of its associated hardware, fittings, and wiring devices, both permanently and temporarily installed, which extends from the load end of the service drop, or load end of the service lateral conductors to the outlet (s). Such wiring does not include wiring internal to appliances, fixtures, motors, controllers, motor control centers, and similar equipment.

Preventative recovery period means a period of time to recover from the heat in order to prevent heat illness.

Protective system means a method of protecting employees from cave-ins, from material that could fall or roll from an excavation face into an excavation, or from the collapse of adjacent structures. Protective systems include support systems, sloping and benching systems, shield systems, and other systems that provide the necessary protection.

Putlog – A scaffold member upon which the platform rests.


Qualified Person: One that has been trained in the repair, construction and operation of electrical equipment and the hazards involved.

Qualified testing laboratory. A properly equipped and staffed testing laboratory which has capabilities for and which provides the following services:

(a) Experimental testing for safety of specified items of equipment and materials referred to in this standard to determine compliance with appropriate test standards or performance in a specified manner;

(b) Inspecting the run of such items of equipment and materials at factories for product evaluation to assure compliance with the test standards;

(c) Service-value determinations through field inspections to monitor the proper use of labels on products and with authority for recall of the label in the event a hazardous product is installed;

(d) Employing a controlled procedure for identifying the listed and/or labeled equipment or materials tested; and

(e) Rendering creditable reports or findings that are objective and without bias of the tests and test methods employed.


Raceway: A channel designed expressly for holding wires, cables, or busbars, with additional functions as permitted in this subpart. Raceways may be of metal or insulating material, and the term includes rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible metal conduit, flexible metallic tubing, flexible metal conduit, electrical metallic tubing, underfloor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways, and busways.

Ramp: an inclined walking or working surface that is used to gain access to one point from another. A ramp may be constructed from earth or from structural materials such as steel or wood.

Readily accessible: Capable of being reached quickly for operation, renewal, or inspections, without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, chairs, etc. (See “Accessible.”)

Receptacle: A receptacle is a contact device installed at the outlet for the connection of a single attachment plug. A single receptacle is a single contact device with no other contact device on the same yoke. A multiple receptacle is a single device containing two or more receptacles.

Receptacle outlet: An outlet where one or more receptacles are installed.

Registered Professional Engineer: a person who is registered as a professional engineer in the state where the work is to be performed. However, a professional engineer, registered in any state is deemed to be a “registered professional engineer” within the meaning of this standard when approving designs for “manufactured protective systems” or “tabulated data” to be used in interstate commerce.

Remote-control circuit: Any electric circuit that controls any other circuit through a relay or an equivalent device.

Rise: The vertical distance from the top of a tread to the top of the next higher tread.

Riser: The upright member of a step situated at the back of a lower tread and near the leading edge of the next higher tread.

Riser Height: The vertical distance from the top of a tread or platform/landing to the top of the next higher tread or platform/landing.

Rolling Ladders: A rolling ladder may only 2 ½ times the least (shortest) base in height

Rope grab: a deceleration device which travels on a lifeline and automatically, by friction, enages the lifeline and locks so as to arrest the fall of an employee. A rope grab usually employs the principle of inertial locking, cam/level locking, or both.

Runway: A passageway for persons, elevated above the surrounding floor or ground level, such as a footwalk along shafting or a walkway between buildings.

Runner: The lengthwise horizontal bracing or bearing members or both.


Safety Violations: Any alleged violation observed during an inspection will be classified as either “serious,” “general,” or “regulatory.” Depending on the circumstances, any of these violations may carry the additional designation of “repeat” or “willful.”

Scaffold: Any temporary elevated platform and its supporting structure used for supporting workmen or materials or both.

Sealable equipment: Equipment enclosed in a case or cabinet that is provided with a means of sealing or locking so that live parts cannot be made accessible without opening the enclosure. The equipment may or may not be operable without opening the enclosure.

Sectional ladder: A sectional ladder is a non-self-supporting portable ladder, nonadjustable in length, consisting of two or more sections of ladder so constructed that the sections may be combined to function as a single ladder. Its size is designated by the overall length of the assembled sections.

Self-retracting lifeline/lanyard means a deceleration device containing a drum-wound line which can be slowly extracted from, or retracted onto, the drum under slight tension during normal employee movement, and which, after onset of a fall, automatically locks the drum and arrests the fall.

Separately derived system: A premises wiring system whose power is derived from generator, transformer, or converter windings and has no direct electrical connection, including a solidly connected grounded circuit conductor, to supply conductors originating in another system.

Service: The conductors and equipment for delivering energy from the electricity supply system to the wiring system of the premises served.

Service conductors: The supply conductors that extend from the street main or from transformers to the service equipment of the premises supplied.

Service drop: The overhead service conductors from the last pole or other aerial support to and including the splices, if any, connecting to the service-entrance conductors at the building or other structure.

Service-entrance conductors, overhead system: The service conductors between the terminals of the service equipment and a point usually outside the building, clear of building walls, where joined by tap or splice to the service drop.

Service-entrance conductors, underground system: The service conductors between the terminals of the service equipment and the point of connection to the service lateral. Where service equipment is located outside the building walls, there may be no service-entrance conductors, or they may be entirely outside the building.

Service equipment: The necessary equipment, usually consisting of a circuit breaker or switch and fuses, and their accessories, located near the point of entrance of supply conductors to a building or other structure, or an otherwise defined area, and intended to constitute the main control and means of cutoff of the supply.

Service raceway: The raceway that encloses the service-entrance conductors.

Servicing (maintenance): Workplace activities such as constructing, installing, setting up, adjusting, inspecting, modifying, maintaining and/or servicing machines or equipment, including lubrication, cleaning or unjamming of machines or equipment, and making adjustments or tool changes, where employees could be exposed to the unexpected energization or startup of the equipment or release of hazardous energy.

Shade: blockage of direct sunlight. Canopies, umbrellas and other temporary structures or devices may be used to provide shade. One indicator that blockage is sufficient is when objects do not cast a shadow in the area of blocked sunlight. Shade is not adequate when heat in the area of shade defeats the purpose of shade, which is to allow the body to cool. For example, a car sitting in the sun does not provide acceptable shade to a person inside it, unless the car is running with air conditioning.

Sheeting: the members of a shoring system that retain the earth in position and in turn are supported by other members of the shoring system.

Shield (Shield system) means a structure used in an excavation to withstand cave-ins and which will protect employees working within the shield system. Shields can be permanent structures or portable units moved along as work progresses. Shields used in trenches are usually referred to as trench boxes or trench shields.

Shoring (Shoring system) means a structure that is built or put in place to support the sides of an excavation to prevent cave-ins.

Side-rolling ladder: A side-rolling ladder is a semifixed ladder, nonadjustable in length, supported by attachments to a guide rail, which is generally fastened to shelving, the plane of the ladder being also its plane of motion.

Sides – See Faces.

Side-Step Fixed Ladder – A fixed ladder that requires a person to get off at the top to step to the side of the ladder side rails to reach the landing.

Signaling circuit: Any electric circuit that energizes signaling equipment.

Silo: a structure for storing bulk materials. Silos are most commonly used for bulk storage of grain, coal, cement, carbon black, woodchips, food products and sawdust. Three types of silos are in widespread use today: tower silos, bunker silos, and bag silos.

Single-Cleat Ladder – A ladder consisting of a pair of side rails connected together by cleats, rungs, or steps.

Sloping (Sloping system): sloping the sides of the excavation away from the excavation to protect employees from cave-ins. The required slope will vary with soil type, weather, and surface or near surface loads that may affect the soil in the area of the trench (such as adjacent buildings, vehicles near the edge of the trench and so forth).

Slow Response – means the setting on the sound level meter that averages out impulses of brief duration that would cause wide fluctuation in the sound level meter reading.

Snaphook means a connector comprised of a hook-shaped member with a normally closed keeper, or similar arrangement, which may be opened to permit the hook to receive an object and, when released, automatically closes to retain the object. Snaphooks are generally one of two types:  (1) The locking type with a self-closing, self-locking keeper which remains closed and locked until unlocked and pressed open for connection or disconnection; or (2) The non-locking type with a self-closing keeper which remains closed until pressed open for connection or disconnection. As of January 1, 1998, the use of a non-locking snaphook as part of personal fall arrest systems and positioning device systems is prohibited.

Special-purpose ladder: A special-purpose ladder is a portable ladder which represents either a modification or a combination of design or construction features in one of the general-purpose types of ladders previously defined, in order to adapt the ladder to special or specific uses.

Stable rock means natural solid mineral material that can be excavated with vertical sides that will remain intact while exposed.

Stair rail System: A vertical barrier erected along the unprotected sides and edges of a stairway to prevent employees from falling to lower levels.

Stalking: Stalking occurs when any person willfully, maliciously and repeatedly follows or harasses another and makes a credible threat with the intent to place that person in reasonable fear for his/her safety or the safety of his/her immediate family.

Standard railing: A vertical barrier erected along exposed edges of a floor opening, wall opening, ramp, platform, or runway to prevent falls of persons.

Standard strength and construction: Any construction of railings, covers, or other guards that meets the requirements of 1910.23

Standard Threshold Shift: means a change in hearing threshold relative to the baseline audiogram of an average of 10 dB (corrected for age) at 2000, 3000 and 4000 Hz in either ear.

Stepladder: A stepladder is a self-supporting portable ladder, nonadjustable in length, having flat steps and a hinged back. Its size is designated by the overall length of the ladder measured along the front edge of the side rails.

Strain Relief: A mechanical device that prevents force from being transmitted to the connections or terminals of a cable or extension cord.

Stair railing: A vertical barrier erected along exposed sides of a stairway to prevent falls of persons.

Structural ramp: a ramp built of steel or wood, usually used for vehicle access. Ramps made of soil or rock are not considered structural ramps.

Sun Stroke: see heat illness

Support system: a structure such as underpinning, bracing, or shoring, which provides support to an adjacent structure, underground installation, or the sides of an excavation.


(a) General-use switch. A switch intended for use in general distribution and branch circuits. It is rated in amperes, and it is capable of interrupting its rated current at its rated voltage.

(b) General-use snap switch. A form of general-use switch so constructed that it can be installed in flush device boxes or on outlet box covers, or otherwise used in conjunction with wiring systems recognized by this subpart.

(c) Isolating switch. A switch intended for isolating an electric circuit from the source of power. It has no interrupting rating, and it is intended to be operated only after the circuit has been opened by some other means.

(d) Motor-circuit switch: A switch, rated in horsepower, capable of interrupting the maximum operating overload current of a motor of the same horsepower rating as the switch at the rated voltage.

Switching devices: (Over 600 volts, nominal.) Devices designed to close and/or open one or more electric circuits. Included in this category are circuit breakers, cutouts, disconnecting (or isolating) switches, disconnecting means, and interrupter switches.


Tabulated data means tables and charts approved by a registered professional engineer and used to design and construct a protective system.

Tagout: The placement of a tagout device on an energy-isolating device, in accordance with an established procedure, to indicate that the energy-isolating device and the equipment being controlled may not be operated until the tagout device is removed.

Tagout device: Any prominent warning device, such as a tag and a means of attachment, that can be securely fastened to an energy-isolating device to indicate that the machine or equipment to which it is attached may not be operated until the tagout device is removed.

Temperature means the dry bulb temperature in degrees Fahrenheit obtainable by using a thermometer to measure the outdoor temperature in an area where there is no shade. While the temperature measurement must be taken in an area with full sunlight, the bulb or sensor of the thermometer should be shielded while taking the measurement, e.g., with the hand or some other object, from direct contact by sunlight.

Temporary Service Stairway – A stairway where permanent treads and/or landings are to be filled in at a later date.

Threat – A threat is a statement (verbal, written or physical) which is intended to intimidate by expressing the intent to either harass, hurt, take the life of another person, or damage/destroy property. This includes threats made in jest but which others could perceive as serious.

Through Fixed Ladder – A fixed ladder that requires a person getting off at the top to step between the side rails of the ladder to reach the landing.

Toeboard – A barrier secured along the sides and ends of a platform, to guard against the falling of material.

Transportable X-ray: X-ray equipment installed in a vehicle or that may readily be disassembled for transport in a vehicle.

Tread Depth – The horizontal distance from front to back of a tread, excluding nosing, if any.

Trench (Trench excavation) means a narrow excavation (in relation to its length) made below the surface of the ground.

Trench box or shield – See Shield.

Trestle ladder: a self-supporting portable ladder, nonadjustable in length, consisting of two sections hinged at the top to form equal angles with the base. The size is designated by the length of the side rails measured along the front edge.

Trolley ladder: a semifixed ladder, nonadjustable in length, supported by attachments to an overhead track, the plane of the ladder being at right angles to the plane of motion.

Tube and coupler scaffold – An assembly consisting of tubing, which serves as posts, bearers, braces, ties, and runners, a base supporting the posts, and special couplers which serve to connect the uprights and to join the various members.

Tubular welded frame scaffold – A sectional, panel, or frame metal scaffold substantially built up of prefabricated welded sections that consist of posts and horizontal bearer with intermediate members. Panels or frames shall be braced with diagonal or cross braces.


Under the influence: means, for the purposes of this policy, that the employee is affected by a drug or alcohol or the combination of a drug and alcohol in any detectable manner.  The symptoms of influence are not confined to those consistent with misbehavior, nor to obvious impairment of physical or mental ability, such as slurred speech or difficulty in maintaining balance.  A determination of influence can be established by a professional opinion, a scientifically valid test and, in some cases such as alcohol, by a layperson’s opinion.

Unprotected sides and edges means any side or edge (except at entrances to points of access) of a walking/working surface, e.g., floor, roof, ramp, or runway where there is no wall or guardrail system at least 39 inches (1.0 m) high.

Uprights: the vertical members of a trench shoring system placed in contact with the earth and usually positioned so that individual members do not contact each other. Uprights placed so that individual members are closely spaced, in contact with or interconnected to each other, are often called sheeting.

Utilization equipment: Utilization equipment means equipment which utilizes electric energy for mechanical, chemical, heating, lighting, or similar useful purpose.

Utilization system: A utilization system is a system which provides electric power and light for employee workplaces, and includes the premises wiring system and utilization equipment.


Ventilated: Provided with a means to permit circulation of air sufficient to remove an excess of heat, fumes, or vapors.

Vocational & return to work counselor (VRTWC): If you have a permanent disability, this is the person or entity that helps you develop a return to work strategy. They evaluate you, provide counseling and help you get ready to work. A VRTWC must have at least an undergraduate degree in any field and three or more years of full time experience.

Vocational rehabilitation (VR): A workers’ compensation benefit. If you were injured before 2004 and are permanently unable to do your usual job, and your employer does not offer other work, you qualify for this benefit. It includes job placement counseling to help you find another job. It may also include retraining and a vocational rehabilitation maintenance allowance.

Vocational rehabilitation maintenance allowance (VRMA): Payments to help you with living expenses while participating in vocational rehabilitation. See vocational rehabilitation.

Volatile flammable liquid: A flammable liquid having a flash point below 38 degrees C (100 degrees F) or whose temperature is above its flash point, or a Class II combustible liquid having a vapor pressure not exceeding 40 psia (276 kPa) at 38 deg. C (100 deg. F) whose temperature is above its flash point.

Voltage: (Of a circuit.) The greatest root-mean-square (effective) difference of potential between any two conductors of the circuit concerned.

Voltage, nominal: A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage class (as 120/240, 480Y/277, 600, etc.). The actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment.

Voltage to ground: For grounded circuits, the voltage between the given conductor and that point or conductor of the circuit that is grounded; for ungrounded circuits, the greatest voltage between the given conductor and any other conductor of the circuit.

Voucher: See supplemental job displacement benefit and nontransferable voucher.


Wage loss (temporary partial disability): See temporary partial disability benefits.

Wales are horizontal members of a shoring system placed in the direction of the excavation face whose sides bear against the vertical members of the shoring system or earth (the uprights or sheeting).

Walking/working surface means any surface, whether horizontal or vertical on which an employee walks or works, including, but not limited to, floors, roofs, ramps, bridges, runways, formwork and concrete reinforcing steel but not including ladders, vehicles, or trailers, on which employees must be located in order to perform their job duties.

Wall hole: An opening less than 30 inches but more than 1 inch high,of unrestricted width, in any wall or partition; such as a ventilation hole or drainage scupper.

Wall opening: An opening at least 30 inches high and 18 inches wide,in any wall or partition, through which persons may fall; such as a yard-arm doorway or chute opening.

Watertight: So constructed that moisture will not enter the enclosure.

Weatherproof. So constructed or protected that exposure to the weather will not interfere with successful operation. Rainproof, raintight, or watertight equipment can fulfill the requirements for weatherproof where varying weather conditions other than wetness, such as snow, ice, dust, or temperature extremes, are not a factor.

Welding/Hot Work Procedures – any activity which results in sparks, fire, molten slag, or hot material which has the potential to cause fires or explosions.

Wood characteristics: distinguishing features which by their extent and number determine the quality of a piece of wood.

Wood characteristics: distinguishing features which by their extent and number determine the quality of a piece of wood.

Work area means that portion of a walking/working surface where job duties are being performed.

Working Load – Load imposed by men, materials, and equipment.

Workplace Violence – Workplace violence is any act or threat of physical violence, harassment, intimidation, or other threatening disruptive behavior that occurs at the work site. It ranges from threats and verbal abuse to physical assaults and even homicide. It can affect and involve employees, clients, customers and visitors.

The three major types of workplace violence are:

  • Type I – The aggressor has no legitimate business relationship to the workplace and usually enters the affected workplace to commit a robbery or other criminal act such as robbery.
  • Type II – The aggressor is either the recipient or the object, of a service provided by the affected workplace or the victim, such as a current or former client, patient, customer, passenger, criminal suspect, inmate or prisoner.
  • Type III – The aggressor has some employment-related involvement with the affected workplace such as a current or former employee, supervisor, manager; a current/former spouse or significant other, a relative, friend; or some other person who has a dispute with an employee of the affected workplace.