7.9.3 - Caravan park installations
These Regulations cover the arrangements
for the supply of electrical energy to individual plugs
on a caravan or tent park. The plots on which caravans will
stand are referred to as caravan pitches.
As mentioned in {7.9.1}
the supply to caravans must not be PME - this means that
only TT or TN-S systems may be used. If the supply system
is PME, there must be separation of the earthing systems
of the pitch supplies and the incoming supply, which is
usually best effected at the main distribution board with
a separate earth electrode for the pitch supplies. The PME
system may be used to supply permanent buildings such as
toilet blocks.
Wherever possible, the supplies to the
plugs should be by means of underground cables (see{7.13.3}).
These cables should be installed outside the area of the
caravan pitch to ensure that they are not damaged by tent
pegs (which are often used in erecting caravan awnings)
and ground anchors which are used to secure the caravans
against the effects of high winds. If the underground cables
must be below the pitches, they must be provided with additional
protection. as shown in {Fig
7.22}.
If overhead supplies are used they must:
1. - be constructed with insulated, rather
than bare, cables
2. - always be at least 2 m outside the area
of every pitch
3. - have a mounting height of at least 3.5
m, which must be increased to 6 m where vehicle movements
are possible. Since in most cases the whole of the area
of a caravan site is subject to vehicle movements, most
overhead systems will need to be at a minimum height of
6 m. Poles or other supports for overhead wiring must be
located or protected so that they are unlikely to be damaged
by vehicle movement.
There must be at least one supply socket
for each pitch, the socket positioned so that it is between
0.8 m and 1.5 m above ground level, and no more than 20
m from any point in its pitch. The current rating must be
at least 16 A, and the outlet must he to BS EN 60309-2,
of the splash proof type to IPX4, and with the keyway at
position 6h. If the expected current demand for a pitch
exceeds 16 A, extra sockets of higher rating must be installed.
A problem frequently arises due to the increasing use of
3 kW instantaneous water heaters in caravans because supply
systems have not usually been designed to allow for such
heavy loading.
Each socket must have its own individual
overcurrent protection in the form of a fuse or circuit
breaker; to ensure that enough current will flow to open
the protective device in the event of an earth fault, it
is recommended that the earth-fault loop impedance at the
plug should not exceed 2 Ohms. All sockets must be protected
by an RCD complying with BS 4293, BS EN 61008-1 or BS EN
61009-1 with a 30 mA rating, either individually or in groups,
which must consist of no more than three sockets (see {Fig
7.12}). Since a 30 mA RCD is also required within each caravan,
the device protecting the pitch socket(s) should be time
delayed, to prevent the possibility of a fault in one caravan
from switching off the supply to other caravans.
Fig 7.12 - RCD protection
for sockets at caravan pitches
