30 CFR § 18.2
As used in this part--
means written notification by MSHA that a hose has met the applicable requirements of this part and will be
listed by MSHA as acceptable flame-resistant auxiliary equipment.
means an identifying marking indicating that the
hose has been accepted by MSHA for listing as flame
means associated electrical equipment, such as a
distribution or splice box, that is not an integral part of an approved
means the Assistant Secretary of Labor for Mine
Safety and Health.
means the combustion of a flammable mixture that is
drawn into a machine compartment after an internal explosion in the
means an individual, partnership, company, corporation,
organization, or association that designs, manufactures, assembles, or
controls the assembly of an electrical machine or accessory and seeks
approval, certification, or permit, or MSHA acceptance for listing of
means a formal document issued by MSHA which states that a
completely assembled electrical machine or accessory has met the applicable
requirements of this part and which authorizes the attachment of an approval
plate so indicating.
means a metal plate, the design of which meets MSHA's
requirements, for attachment to an approved machine or accessory, identifying
it as permissible for use in gassy mines or tunnels.
means an electrical circuit connected to the main
circuit, the conductors of which are of smaller size than the main
means the U.S. Bureau of Mines.
means a formal written notification, issued by MSHA,
which states that an electrical component complies with the applicable
requirements of this part and, therefore, is suitable for incorporation in
approved (permissible) equipment.
means a plate, label, or marking, the design of
which meets MSHA's requirements, for attachment to a certified component
identifying the component as having met the MSHA's requirements for
incorporation in a machine to be submitted for approval.
means an integral part of an electrical machine or
accessory that is essential to the functioning of the machine or
(also known as conduit or terminal box) means an
enclosure mounted on an electrical machine or accessory to facilitate wiring,
without the use of external splices. (Such boxes may have a joint common with
an explosion-proof enclosure provided the adjoining surfaces conform to the
requirements of Subpart B of this part.)
means a joint comprised of two contiguous,
concentric, cylindrical surfaces.
means an enclosure through which one or more
portable cables may be connected to a source of electrical energy, and which
contains a short-circuit protective device for each outgoing cable.
means any electrical machine or accessory that
an applicant or MSHA may desire to operate experimentally for a limited time
in a gassy mine or tunnel. (For example, this might include a machine
constructed at a mine, an imported machine, or a machine or device designed
and developed by MSHA.)
means an enclosure that complies with the
applicable design requirements in Subpart B of this part and is so
constructed that it will withstand internal explosions of methane-air
mixtures: (1) Without damage to or excessive distortion of its walls or
cover(s), and (2) without ignition of surrounding methane-air mixtures or
discharge of flame from inside to outside the enclosure.
means two or more adjoining or adjacent surfaces
between which the escape of flame is prevented.
as applied to cable, hose, and insultating materials
means material that will burn when held in a flame but will cease burning
when the flame is removed.
means a mixture of methane or natural gas and air
that when ignited will propagate flame. Natural gas containing a high
percentage of methane is a satisfactory substitute for pure methane in most
means a coal mine classed as "gassy" by MESA or by the
State in which the mine is situated.
Incendive arc or spark
means an arc or spark releasing enough
electrical or thermal energy to ignite a flammable mixture of the most easily
means incapable of releasing enough electrical or
thermal energy under normal or abnormal conditions to cause ignition of a
flammable mixture of methane or natural gas and air of the most easily
means the United States Department of the Interior, Mining
Enforcement and Safety Administration. Predecessor organization to MSHA,
prior to March 9, 1978.
means equipment that is self-propelled.
means the United States Department of Labor, Mine Safety and
means the regular performance of those functions for
which a machine or accessory was designed.
means a completely assembled electrical machine
or accessory for which a formal approval has been issued, as authorized by
the Administrator, Mining Enforcement and Safety Administration under the
Federal Coal Mine Health and Safety Act of 1969 (Pub. L. 91-173, 30 U.S.C.
801 or, after March 9, 1978, by the Assistant Secretary under the Federal
Mine Safety and Health Act of 1977 (Pub. L. 91-173, as amended by Pub. L.
95-164, 30 U.S.C. 801).
means a formal document, signed by the Assistant Secretary,
authorizing the operation of specific experimental equipment in a gassy mine
or tunnel under prescribed conditions.
means two adjoining surfaces in parallel planes.
or trailing cable
means a flame-resistant,
flexible cable or cord through which electrical energy is transmitted to a
permissible machine or accessory. (A portable cable is that portion of the
power-supply system between the last short-circuit protective device,
acceptable to MSHA, in the system and the machine or accessory to which it
transmits electrical energy.)
means equipment that may be moved frequently and
is constructed or mounted to facilitate such movement.
means a component that is entirely embedded in a
solidified insulating material within an enclosure.
means the development of abnormal pressure as a
result of accelerated rate of burning of a gas-air mixture. (Frequently
caused by restricted configurations within enclosures.)
means a person authorized by MSHA to
determine whether the applicable requirements of this part have been complied
with in the original manufacture, rebuilding, or repairing of equipment for
which approval, certification, or a permit is sought.
means a portable enclosure in which electrical conductors
may be joined.
means a joint comprised of two
adjoining surfaces with a change(s) in direction between its inner and outer
edges. (A step joint may be composed of a cylindrical portion and a plane
portion or of two or more plane portions.)
means a joint consisting of a male- and a
female-threaded member, both of which are of the same type and gage.
[33 FR 4660, Mar. 19, 1968, as amended at 39 FR 23999, June 28, 1974; 43 FR
12314, Mar. 24, 1978; 57 FR 61223, Dec. 23, 1992]