Definitions Applicable to 29 CFR 1926 Subpart K cont'd

DOE-HDBK-1092-2004

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.

Certified--Equipment is "certified" if it:

a. has been tested and found by a qualified testing laboratory to meet applicable test

standards or to be safe for use in a specified manner, and

b. is of a kind whose production is periodically inspected by a qualified testing laboratory.

Certified equipment must bear 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.

Class I locations--Class I locations are those in which flammable gases or vapors are or may

be present in the air in quantities sufficient to produce explosive or ignitable mixtures. Class I

locations include the following:

a. Class I, Division I--A Class 1, Division 1 location is a location:

1. in which ignitable concentrations of flammable gases or vapors may exist under normal

operating conditions; or

2. in which ignitable concentrations of such gases or vapors may exist frequently because

of repair or maintenance operations or because of leakage; or

3. in which breakdown or faulty operation of equipment or processes might release

ignitable concentrations of flammable gases or vapors, and might also cause

simultaneous failure of electric equipment.

NOTE: This classification usually includes locations where volatile flammable liquids or liquefied

flammable gases are transferred from one container to another; interiors of spray booths

and areas in the vicinity of spraying and painting operations where volatile flammable

solvents are used; locations containing open tanks or vats of volatile flammable liquids;

drying rooms or compartments for the evaporation of flammable solvents; inadequately

ventilated pump rooms for flammable gas or for volatile flammable liquids; and all other

locations where ignitable concentrations of flammable vapors or gases are likely to occur in

the course of normal operations.

b. Class I, Division 2--A Class I, Division 2 location is a location:

1. in which volatile flammable liquids or flammable gases are handled, processed, or used,

but in which the hazardous liquids, vapors, or gases will normally be confined within

closed containers or closed systems from which they can escape only in case of

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