Electric Safety Terminology

Accessible (as applied to equipment) — Admitting close approach; not guarded by locked doors, elevation, or other effective means.

Accessible, Readily — 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, and so forth. Approved — Acceptable to the authority having jurisdiction .

Arc Blast — Explosive release of molten material from equipment caused by highamperage arcs.

Arc Rating — The maximum incident energy resistance demonstrated by a material (or a layered system of materials) prior to breakopen or at the onset of a second‐degree skin burn.  Arc rating is normally expressed in calories per centimeter squared (cal/cm2).  Breakopen is a material response evidenced by the formation of one or more holes in the innermost layer of flame‐resistant material that would allow flame to pass through the material. Conductive — Suitable for carrying electric current.

Deenergized — Free from any electrical connection to a source of potential difference and from electrical charge; not having a potential different from that of the earth.

Note: De‐energized does not describe a safe condition.

Electrical Hazard — A dangerous condition such that contact or equipment failure can result in electric shock, arc flash burn, thermal burn, or blast injury.

Electrical Safety — Recognizing hazards associated with the use of electrical energy and taking precautions so those hazards do not cause injury or death.

Electrically Safe Work Condition (also refer to Verified Deenergized) — A state in which the conductor or circuit part to be worked on or near has been disconnected from energized parts, locked/tagged in accordance with established standards, tested to ensure the absence of voltage, and grounded if determined necessary.

Enclosed — Surrounded by a case, housing, fence, or wall(s) that prevents persons from accidentally contacting energized parts.

Energized (also refer to Live Parts) — Electrically connected to or having a source of voltage.

Exposed (as applied to live parts) — Capable of being inadvertently touched or approached nearer than a safe distance by a person.  It is applied to parts that are not suitably guarded, isolated, insulated, or enclosed.

Flame‐Resistant (FR) — The property of a material whereby combustion is prevented, terminated, or inhibited following the application of a flaming or nonflaming source of ignition, with or without subsequent removal of the ignition source.

Flash Hazard — A dangerous condition associated with the release of energy caused by an electric arc.

Flash Hazard Analysis — A study investigating a worker’s potential exposure to arc‐flash energy, conducted for the purpose of injury prevention and the determination of safe work procedures and the appropriate levels of personal protective equipment (PPE).

Flash Protection Boundary — An approach limit at a distance from exposed live parts beyond which a person could receive a second degree burn if an electrical arc flash were to occur.

Grounded ‐ Connected to earth or to some conducting body that serves in place of the earth.

ELCB/GFCI ‐ An electrical safety device that functions by sensing leakage of current to ground associated with electrical shock and de‐energizing the circuit when the leakage current going beyond the pre‐designed value. National Standards and regulations determine the performance parameters of ELCBs .

Guarded — Covered, shielded, fenced, enclosed, or otherwise protected by means of suitable covers, casings, barriers, rails, screens, mats, or platforms to remove the likelihood of approach or contact by persons or objects to a point of danger.

Incident Energy — The amount of energy impressed on a surface, a certain distance from the source, generated during an electrical arc event.  One of the units used to measure incident energy is calories per centimeter squared (cal/cm2).

Insulated — Separated from other conducting surfaces by a dielectric (including air space) offering a high resistance to the passage of electric current.

Limited Approach Boundary — An approach limit at a distance from an exposed live part at or beyond which a shock hazard exists.

Live Parts (also refer to Energized) — Energized conductive components.

Mobile Equipment — Electric welders, mobile pump sets, portable light standards, etc., that can be readily moved.

Overload — Operation of equipment in excess of normal, full‐load rating, or of a conductor in excess of rated that, when it persists for a sufficient of time, would cause damage or dangerous overheating.  A fault, such as a short circuit or ground fault, is not an overload.

Portable Equipment  — Hand‐held tools, extension etc., that are intended to be carried or moved while the electricity supply is connected and are normally used in heavy operating environments such as workshops, mining areas, areas, and construction sites.

Prohibited Approach Boundary — An approach limit at a distance from an exposed live part at/beyond which work is considered the same as making contact with live part.

Restricted Approach Boundary — An approach limit at a distance from an exposed live part at or beyond which there is an increased risk of shock, due to electrical arc combined with inadvertent movement, for personnel working in close proximity to the live part.

Shock Hazard — A dangerous condition associated with the possible release of energy caused by contact or approach to live parts.

Stationary Equipment — Room air conditioners, refrigerators, office and kitchen equipment, water coolers, and workshop equipment that cannot normally be moved while in service.

Verified Deenergized (also refer to Electrically Safe Work Condition) —  A state in which the conductor or circuit part to be worked on or near has been disconnected from energized parts, locked/tagged in accordance with established requirements, tested to ensure the absence of voltage, and grounded if determined necessary.

Voltage (of a circuit) — The greatest root‐mean‐square (rms) (effective) difference of potential between any 2 conductors of the circuit concerned.

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 conductors and any other conductor of the circuit.

Working Near (live parts) — Any activity performed at or beyond a limited approach boundary.

Working On (live parts) — Coming in contact with live parts with the hands, feet, or other body parts, with tools, probes, or with test equipment, regardless of the PPE a person is wearing.

 

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