Knockouts must only be removed if cables are to enter the cabinet at that point. The
hole must be covered by the trunking or conduit or by means of a blanking grom-
It must not be possible to push a finger or similar size object or instrument into any
hole or cable entry point.
Mains Supply Connections
The connection to the a.c. mains supply must be made by a competent, qualified
person, for example NICEIC approved, in accordance with the current IEE and
local supply regulations.
A means of isolation from the mains supply must be provided within two meters of
the control. This is normally a fused spur fitted with a 3 A fuse.
Where a flexible cable is connected to the control having cores coloured brown and
blue, it is important to connect the wires according to the following code:
Blue: Neutral – connect to terminal N
Brown: Live – connect to terminal L
Where a non-flexible cable is connected to the control having cores coloured red
with black sleeves, it is important to connect the wires according to the following
Black: Neutral – connect to terminal N
Red: Live – connect to terminal L
The insulation of each conductor must be prepared and connected such that no part
of the bare conductor is visible or protruding outside the terminal block, and in the
case of standard conductors, that all the strands are twisted together and firmly
clamped in the terminal. The outer covering insulation must be clamped under a
cable clamp. It is important that this cable enters the control panel enclosure through
the mains entry hole provided, is not looped within the control panel enclosure and
does not run close to other system cables inside or external to the enclosure.
The control panel enclosure must not be opened before isolating the mains supply.
The green Illumination of the green power LED indicates the presence of a.c. mains
supply. The cover must be securely fitted in normal use.
The conductors of the mains supply cable must have a minimum cross-sectional area
of 0.75 mm and the insulating material on each conductor must be a minimum of 0.4
mm thick Polyvinyl Chloride (PVC). Flexible cables must conform to the requirements
of BS6500 and IEC Publication 227. Non-flexible electrical installation cables must
conform to BS6004.