.Electrical installations and wiring systems
323
When heavier cables, trunking, conduit luminaires have fixed a
screw fixing often needed.
Rawlbolts are for heavy-duty masonry fixings (see Fig.
Definition
The most well known expansion bolt
is made Rawlbolt and consists of
a split iron shell held together one
end steel ferrule and spring
wire clip the other end.37
Screw fixing plastic plug.
Rawlbolts are for heavy-duty masonry
fixings. The plastic plug is
inserted into the hole and tapped home until level with the surface of
the masonry.38
Expansion bolt fixing. Each size of
plastic plug colour coded match
a wood screw size.
Drill hole masonry Insert plug Drive home screw
Fixture
FIGURE 14.
PLASTIC PLUGS
A plastic plug made hollow plastic tube split half its length to
allow for expansion. 14.
EXPANSION BOLTS
The most well known expansion bolt made Rawlbolt and consists of
a split iron shell held together one end steel ferrule and spring
wire clip the other end.38).37). Each size plastic plug colour coded match a
wood screw size.
A hole drilled into the masonry, using masonry drill the same diam-
eter, the length the plastic plug (see Fig. 14.
Definition
A plastic plug made hollow
plastic tube split half its length
to allow for expansion.
Drill hole in
masonry
Tighten bolt
until fixture is
secure
Fixture
Insert shell and
ferrule hole
and attach fixture
with bolt
Fixture
Shell
Ferrule
Expanding nut
FIGURE 14. Finally, the fixing screw driven into the plastic plug until it
becomes tight and the fixture secure. Tightening the bolt draws expanding bolt
inside the split iron shell, forcing the iron expand and grip the masonry. Tightening
the bolt draws expanding bolt
inside the split iron shell, forcing the
iron expand and grip the masonry. Wood screws may screwed directly into
wood but when fixing brick, stone, plaster concrete necessary to
drill hole the masonry material, which then plugged with material
to which the screw can secured
