Maximum diameter hole should 0.25 span.
4.Electrical installations and wiring systems
305
Trap provides inspection
access under floorboards
to joint box
Floorboards
Cables passing through
holes drilled joists
Plaster finish wall
Metal switch box
PVC cable run down wall and
buried plaster, covered with
channel mechanical protection
is required
Plasterboard
finish ceiling
Wall
FIGURE 14. Notches top zone between 0.1 and
0.
1.25
and 0. Holes the same joist should least
3 diameters apart.
.
Protection required unless cable
depth greater than 50mm
No protection
required
150mm
150mm
Wall
Wall
Wall
No protection
required
Accessory
boxes
FIGURE 14. Holes centre line zone between 0.
3.23
Correct installation cables floor joists.
2.25
joist depth. Maximum depth notch should 0.
5.
Floor
joists
Steel
conduit
Greater than
50mm
Insulated
and
sheathed
cable
Notes:
FIGURE 14.125
joist depth.22
Permitted cable routes.21
A concealed PVC sheathed wiring system.4 span
