Hardware Installation: Fasteners, Fittings, Fixtures and Mounting
What this domain tests
Hardware Installation tests fasteners, anchors, fittings, fixtures and mounting methods, including load safety and earthing of metal parts.
Core rules
- Wood screws hold in timber; machine screws need a nut or threaded hole; self-tapping screws cut their own thread in sheet metal or plastic; anchor bolts and expansion anchors hold in masonry or concrete.
- A wall plug transfers load to the masonry. The drill size must match the plug, and the hole must be deep enough for the screw to expand the plug.
- For heavy fixtures such as ceiling fans, use a purpose-made fan hook or anchor rated for several times the load. A plastic plug in plaster is not acceptable.
- Mount switch boxes, DBs and fixtures plumb and level, with accessible fixing screws and enough space for wiring.
- Metal fixtures and enclosures must be earthed. Use a star washer or earth terminal to maintain continuity.
- Avoid drilling into concealed cables or pipes; check the route first.
Worked example
A 10 kg ceiling fan is to be mounted on an RCC ceiling. The fixing must carry at least four times the static load, so a 10 mm wedge anchor or an embedded MS hook is selected, not a plastic plug. The fan box is fixed independently, the downrod is secured, and the metal body is bonded to the earth wire.
Traps that cost marks
Using plastic plugs for heavy loads; over-tightening and cracking the plug or tile; fixing into weak plaster; forgetting the earth tail to a metal fixture; and drilling blindly into a wall.