Definitions cont'd - hdbk10920280

DOE-HDBK-1092-98

Exposed--Not isolated or guarded.

Ground--A conducting connection, whether intentional or accidental, between an electric circuit or

equipment and the earth, or to some conducting body that serves in place of the earth.

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

Guarded--Covered, fenced, enclosed, or otherwise protected, by means of suitable covers or

casings, barrier rails or screens, mats, or platforms, designed to minimize the possibility, under

normal conditions, of dangerous approach or accidental contact by persons or objects.

NOTE: Wires which are insulated, but not otherwise protected, are not considered as guarded.

Hazardous atmosphere means an atmosphere that may expose employees to the risk of death,

incapacitation, impairment of ability to self-rescue (that is, escape unaided from an enclosed space),

injury, or acute illness from one or more of the following causes:

1. Flammable gas, vapor, or mist in excess of 10 percent of its lower flammable limit (LFL);

2. Airborne combustible dust at a concentration that meets or exceeds its LFL;

NOTE: This concentration may be approximated as a condition in which the dust obscures vision

at a distance of 5 feet (1.52 m) or less.

3. Atmospheric oxygen concentration below 19.5 percent or above 23.5 percent;

4. Atmospheric concentration of any substance for which a dose or a permissible exposure limit is

published in Subpart G, Occupational Health and Environmental Control, or in Subpart Z, Toxic

and Hazardous Substances, of this Part and which could result in employee exposure in excess

of its dose or permissible exposure limit; Note: An atmospheric concentration of any substance

that is not capable of causing death, incapacitation, impairment of ability to self-rescue, injury,

or acute illness due to its health effects is not covered by this provision.

5. Any other atmospheric condition that is immediately dangerous to life or health.

NOTE: For air contaminants for which OSHA has not determined a dose or permissible exposure

limit, other sources of information, such as Material Safety Data Sheets that comply with the

Hazard Communication Standard, 1910.1200 of this Part, published information, and internal

documents can provide guidance in establishing acceptable atmospheric conditions.

High-power tests--Tests in which fault currents, load currents, magnetizing currents, and line-

dropping currents are used to test equipment, either at the equipment's rated voltage or at lower

voltages.

High-voltage tests--Tests in which voltages of approximately 1000 volts are used as a practical

minimum and in which the voltage source has sufficient energy to cause injury.

High wind--A wind of such velocity that the following hazards would be present:

1. An employee would be exposed to being blown from elevated locations, or

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