http://www.mikeholt.com/onlinetraining/page_images/6_15_34_2_2.gif
This rule was revised to read:
(A) Unused Opening. Unused cable or raceway openings in boxes, auxiliary gutters, cabinets, cutout boxes, meter socket enclosures, equipment cases, must be effectively closed by a fitting that will provide protection substantially equivalent to the wall of the equipment. Figure 110–1Intent: The wording used in the 1999 NEC stated “Unused openings in boxes…” The intent of the change was to prevent this rule from being applied to weep holes in enclosures designed for use in a wet location. In addition, this wording allows ventilation openings or other openings that are a legitimate part of the equipment design.
My Comments - Figured you guys might want to see some images of the idea of the openings…Courtesy of Mike Holt Enterprises…Oh yeah…call them as see if it is ok for me to post them…I am listed as an instructor with them…permission GRANTED…