18
MERLIN 4
Appendix A Cont’d
Warning signs shall be placed at
-
each gate
-
each access point
-
intervals not exceeding 10m
-
adjacent to each sign relating to chemical hazards for the
information of emergency services.
Gates in electric security fences shall be capable of being opened without the
person receiving an electric shock.
The energiser earth electrode shall penetrate the ground to a depth of at
least 1m. The distance between any electric security fence earth electrode
and other earth systems shall not be less than 2m.
Connecting leads that are run inside buildings shall be effectively insulated
from the earthed structural parts of the building. This may be achieved by
using insulated high voltage cable.
Connecting leads that are run underground shall be run in a conduit of
insulating material or else insulated high voltage cable shall be used. Care
shall be taken to avoid damage to the connecting leads due to external
factors.
Connecting leads shall not be installed in the same conduit as the mains
supply wiring, communication cables or data cables.
Connecting leads and electric fence wires shall not cross above overhead
power or communication lines.
Mains supply wiring shall not be installed in the same conduit as signalling
leads associated with the electric security fence installation.
Crossings with overhead power lines shall be avoided wherever possible. If
such a crossing cannot be avoided, it shall be made underneath the power
line and as nearly as possible at right angles to it.
If connecting leads and electric fence wires are installed near an overhead
power line, the clearances shall not be less than those shown in Table 1.
Power Line Voltage (V)
Clearance(m)
Equal or less than 1 000
3
>1 000 and equal or less than 33 000
4
>33 000
8
Table 1
If connecting leads and electric fence wires are installed near an overhead
power line, their height above the ground shall not exceed 3m.
