314.15 Damp or Wet Locations. In damp or wet locations,
boxes, conduit bodies, outlet box hoods, and fittings shall be
placed or equipped so as to prevent moisture from entering or
accumulating within the box, conduit body, or fitting. Boxes,
conduit bodies, outlet box hoods, and fittings installed in wet
locations shall be listed for use in wet locations. Approved
drainage openings not smaller than 3 mm (1∕8 in.) and not
larger than 6 mm (1∕4 in.) in diameter shall be permitted to be
installed in the field in boxes or conduit bodies listed for use in
damp or wet locations. For installation of listed drain fittings,
larger openings are permitted to be installed in the field in
accordance with manufacturer’s instructions.