UFC 3 -520-01
June 10, 2002
Provide all pull boxes, junction boxes, and fittings with covers approved for
the purpose. Ground metal covers if they are used. In completed installations, install a
cover, faceplate, or fixture canopy on each outlet box. Provide covers of outlet boxes
having holes through which flexible cord pendants pass with bushings designed for the
purpose or furnish with smooth, well -rounded surfaces on which the cords can bear.
Ensure pull and junction boxes for systems over 600 volts provide a complete
enclosure for the contained conductors or cables. Close boxes by suitable covers
securely fastened in place. This requirement also applies to underground box covers
that weigh over 45.5 kilograms (100 pounds). Permanently mark covers for boxes with
"DANGER--HIGH VOLTAGE. KEEP OUT." Install the marking on the outside of the
box cover, and ensure it is readily visible and legible.
Wiring systems in hazardous locations must conform to the NEC for the
particular hazard encountered. Outline the extent of each hazardous location on project
construction drawings, describing the applicable vertical and horizontal limits of the
hazard and identifying each hazardous location by NEC Class, Division, and Group or
by Zone (refer to paragraph 8 -3 for a description of hazardous locations ). Designation
of either specific maximum operating temperatures of equipment or temperature ranges
should also be indicated. The following considerations apply to hazardous locations:
6-1.16.1 Require sealing fittings to be shown on the drawings where needed to ensure
compliance with NEC criteria.
6-1.16.2 Locate electrical equipment in nonhazardous areas of facilities having
hazardous locations. Exceptions to this requirement include lighting fixtures in paint-
spray booths and similar situations where electrical equipment must be located within a
hazardous location due to functional requirements.
6-1.16.3 Instances do occur where military terminology is not expressed in terms
consistent with the civilian sector. In such cases, the function to be performed should
govern the requirement for hazardous location design. As an example, repair shops in
vehicle or motor maintenance facilities and self-help garages are normally considered
hazardous locations similar to commercial garages with regard to function. Accordingly,
follow NEC requirements for commercial garages for such a military-equivalent facility.
WIRING SYSTEM CRITERIA.
Wiring systems consist of insulated cond uctors installed in raceways, except
that in combustible construction, branch circuit wiring can consist of metal-clad or
moisture- and corrosion-resistant nonmetallic sheathed cables installed in areas as
permitted by the NEC. Conceal raceways and cables wherever possible in finished
Size conductors to satisfy the electrical requirements of the system. As a
minimum, size conductors at 125 percent of the associated breaker continuous current