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 non-metallic 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. FSM

For more information on explosion proof material handling equipment, visit Gregory Industrial Trucks at www.exequipment.com.