Types E, ES, EE and EX
The NFPA defines eleven Powered Industrial Truck Designations. Included are designations for diesel, gas, propane and electric powered trucks. The four electric powered truck designations are: E, ES, EE and EX.

Type Designation E
"An electrically powered unit that has minimum acceptable safeguards against inherent fire and electrical shock hazards."  NFPA 505(2002) 3.3.2.7

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.

Type Designation ES
"An electrically powered unit that, in addition to meeting all the requirements for Type E units, is provided with additional safeguards to the electrical system to prevent the emission of hazardous sparks and to limit surface temperatures." NFPA 505(2002) 3.3.2.9

In Type ES construction, safeguards are taken to protect against sparks and to limit the surface temperatures generated by the use of selector speed resistors. In terms of safety, a Type ES truck is rated lower than a Type EE truck. 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.

Type Designation EE
"An electrically powered unit that, in addition to meeting all the requirements for Type E and ES units, has its electrical motors and all other electrical equipment completely enclosed." NFPA 505(2002) 3.3.2.8

In Type EE construction, 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.

A Type EE rating 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.

Type 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.

Articles 500-504 of the National Electric Code define and set forth the rigid requirements for each EX truck labeled for use in Class I, Divisions I, II, Groups C, D and Class II, Divisions I, II, Group G. Gregory EX Trucks meet or exceed all of these requirements.

Type EE vs. Type EX
Type EE trucks are authorized for use in Division 2 designated hazardous areas, while Type EX trucks are authorized for use in both Division 1 and Division 2. Under normal conditions in a Division 1 area, hazardous concentrations of flammable gases, vapors or dusts can exist all of the time. In Division 2 areas, hazardous concentrations are not likely to exist and are normally prevented by keeping flammable liquids, gases or dusts in closed containers.

EE trucks are used in Division 2 areas where flammable or explosive materials are stored in sealed containers. However, if a sealed container or drum is pierced by a fork or dropped, the resulting leak or rupture makes the Division 2 area immediately volatile and creates an instantaneous Division 1 environment. Under these circumstances, the use of an EE Truck is no longer safe and could result in a fire or explosion.