17.3.3 An insulated lining or barrier of vulcanized fiber or similar material used where a spacing would
otherwise be less than the minimum shall not be less than 1/32 inch (0.8 mm) thick and shall be so located
or of such material that it will not be adversely affected by arcing.
Exception No. 1: Vulcanized fiber not less than 1/64 inch (0.4 mm) thick may be used in conjunction with
an air-spacing of not less than 50 percent of the minimum through-air spacing.
Exception No. 2: Insulating material thinner than that specified may be used if investigated and found to
be acceptable for the application.
发表于 2011-9-6 21:38:16
收藏
发表于 2011-9-7 08:18:41