1 and
0. Maximum diameter hole should 0.4 span.
Floor
joists
Steel
conduit
Greater than
50mm
Insulated
and
sheathed
cable
Notes:
FIGURE 14.21
A concealed PVC sheathed wiring system.25 span.25
joist depth.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.
1.125
joist depth. Maximum depth notch should 0.
4.
Protection required unless cable
depth greater than 50mm
No protection
required
150mm
150mm
Wall
Wall
Wall
No protection
required
Accessory
boxes
FIGURE 14.23
Correct installation cables floor joists.
3.
. Notches top zone between 0. Holes centre line zone between 0.22
Permitted cable routes.
2.25
and 0. Holes the same joist should least
3 diameters apart.
5
