Every year, millions of injuries
occur both on and off
the job. Some say it is a
silent epidemic.
In locations where flammable or combustible
liquids, gases, vapors or dusts
may be released into the atmosphere,
electric powered industrial equipment must
be designed to prevent any operation of the
equipment from igniting the atmosphere.
The NFPA has defined Powered Industrial
Truck Designations for diesel, gas,
propane and electric powered trucks. The
four electric powered truck designations, according
to NFPA 505(2002) 3.3.2.7, are: E,
ES, EE and EX.
Designation E: “An electrically powered
unit that has minimum acceptable safeguards
against inherent fire and electrical shock
hazards.” In Type E construction, wiring
should always be of adequate size for the
current carried, placed where it is not
subject to external damage, and kept
clear of grease or other flammable materials.
This rating covers only normal design
and construction. Type E trucks are
used in ordinary (unclassified) locations.
Designation ES: “Provides additional
safeguards to the electrical system to prevent
the emission of hazardous sparks and to limit
surface temperatures.”
A Type ES truck can be used in some Division
2 designated hazardous areas, however
Type ES trucks cannot be used in any
Division 1 designated hazardous area.
Designation EE: “Motors and switches
should be enclosed to prevent sparks from
escaping, and flexible leads should be in nonmetallic
looming or tubing. A Type EE truck
is authorized for use in some Division 2 designated
hazardous areas, but does not protect
against explosive mixtures of gases or
dusts in the atmosphere. The EE rating does
not protect against: static discharges in atmosphere,
auto ignition temperatures generated
during normal forklift operation or
electrical system failures.
A Type EE truck
cannot be used in any Division 1 designated
hazardous area.
Designation EX: “An electrically powered
unit in which the electrical fittings and equipment are so designed, constructed, and assembled
that the unit can be used in atmospheres
containing specifically named
flammable vapors, dusts, and, under certain
conditions, fibers.” NFPA 505(2002)
3.3.2.10
A Type EX truck must meet the fire and
shock hazard requirements of UL 583. In addition,
EX trucks must have Explosion Proof
enclosures (for Class I, Division 1) and dust ignition-
proof enclosures (for Class II, Division
1), in accordance with UL 1203. EX
trucks (for Classes I and II, Division 2 and
Class III) must meet UL 1604 requirements
in which the circuits and components are incapable
of causing ignition of the flammable
gases or vapors in the environment.
