Ground-Fault Circuit Interrupter

DOE-HDBK-1092-2004

relative humidity because of the possibility of their spontaneous ignition. Where this technique is

used to prevent accumulations of static electricity, a daily check of the humidity levels will be

performed before work starts.

5.1.4.7 GROUND-FAULT CIRCUIT INTERRUPTER

GFCI protection shall be provided in static-grounded areas where personnel are using hand-

held, portable, ac-powered electrical equipment operating at 120 V.

5.1.5

ELECTRICAL EQUIPMENT AND WIRING

Electrical equipment and wiring in locations containing explosives shall comply with relevant

provisions of the NEC and DOE regulations, plus the requirements in this section.

5.1.5.1 PERMANENT EQUIPMENT AND WIRING

The NEC and this section are minimum requirements for DOE facilities containing explosives.

Though the NEC does not specifically address explosives, Article 500, Hazardous (Classified)

Locations, does establish requirements for the design and installation of electrical equipment

and wiring in locations containing combustible dusts and flammable liquids, vapors, or gases

that in general are comparably hazardous. All permanent electrical equipment and wiring in

work areas containing explosives hazards shall conform to the standards of the NEC Hazardous

Locations Class II or Class I and II (dual rated). For Class II installations, provisions should be

made for easy conversion to Class I.

5.1.5.2 HAZARDOUS LOCATIONS

NEC definitions of and requirements for hazardous locations Class I and Class II are modified

as follows for application to DOE explosives facilities:

1. Areas containing explosive dusts or explosives which may, through handling or processing,

produce dust capable of being dispersed in the atmosphere shall be regarded as Class II

Division 1 hazardous locations.

2. Areas that contain exposed explosives but where no dust hazard exists shall be regarded as

Class 11 Division 2 hazardous locations.

3. Suitable National Electrical Manufacturers Association (NEMA)-rated enclosures shall be

provided in those locations where water/ explosives mixtures may contact electrical

equipment and wiring.

4. Areas where explosives are processed and sublimation may occur or where flammable

gases or vapor may be present in quantities sufficient to produce explosive or ignitable

mixtures shall be regarded as Class I Division 1 and Class II Division 1 hazardous locations.

5. To ensure a location is assigned to the proper hazardous location class and division, it is

necessary to know the properties of the explosives involved there, including, at a minimum,

sensitivity to heat and spark and thermal stability. If the properties of an explosive area are

such that Class II Group G equipment provides inadequate surface temperature limits,

special protection shall be provided or the equipment excluded from the hazardous location.

This equipment shall not have a surface temperature exceeding the lowest onset of the

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