A slug is the round piece of steel that comes out of a knockout or is cut by a knockout punch. Slugs collect in the bottoms of panels and boxes and must be cleaned out before energising, because a loose slug can bridge live parts or jam a breaker. Some punches split the slug in two so it falls out of the die instead of having to be pried loose.
Vacuum the slugs out of that panel before trim, the inspector found three under the neutral bar last time.
Also heard as
- knockout slug
Related terms
KO
Knockout: a partly punched disc in a box or panel that is removed to make a hole for a conduit or cable fitting.
Knockout punch
Punch and die set that shears clean round holes in boxes and panels for conduit fittings.
Tub
Empty panel enclosure, the steel back box that goes in at rough-in before the interior and cover arrive.