Tapcon is a brand of masonry screw used generically for any thread-cutting concrete screw. A pilot hole is drilled with a carbide bit, 3/16 inch for a 1/4 inch screw and 5/32 inch for a 3/16 inch screw, and the screw cuts its own thread as it is driven, with no separate anchor. It is the standard fastener for straps, boxes and panels on block and poured walls, and it can be backed out, though a reused hole holds less.
Two Tapcons through the back of the disconnect into the block, use the three-sixteenths bit for the quarter-inch screws.
Also heard as
- concrete screw
- masonry screw
Related terms
One-hole strap
Conduit strap with a single screw hole, used to fasten a conduit run to a wall or structure.
Red head
Plastic anti-short bushing pushed into the cut end of armored cable to shield wires from the sharp armor edge.
Handy box
Small surface-mount steel utility box with rounded corners, used for exposed switches and outlets on block walls.