4 مدخل الخدمة

SECTION 4

SERVICE INTAKE

401 A building or premises shall normally be provided with only one service intake by the Ministry of Electricity
and Water.

EXCEPTIONS: 1. Where the total connected load requirements are in excess of 200 KVA and the prior
approval of the Ministry of Electricity and Water has been obtained, two or more
service intakes may be permitted. In all such cases the electrical installations shall
be so designed and arranged that each supply caters to a distinct and separate part of
the building.

2. A second service intake may also be allowed for a building to serve an electrically
operated fire pump provided the local Fire Authorities have approved the
installation of such a pump without requiring its connection to an alternate source
of emergency power.

402 The Ministry of Electricity and Water shall normally provide a three phase and neutral service and the
consumers electrical installations shall be arranged for connection to the three phases. In special situations where
the total connected load is less than 10 KVA, the Ministry of Electricity and Water may provide a single phase and
neutral service.

403 Where the total connected load requirements of any building is in excess of 400 KVA the consumer may be
required to provide within his own premises and at an approved location adequate space for the installation of an
electrical sub-station.

404 The sub-station shall comprise of an 11KV switchboard and one or more 11/0.433KV transformers, all of
which will be provided by the Ministry of Electricity and Water. The low tension switchboard controlling the
electrical installations of the building or premises shall be supplied by the consumer in case the sub-station is purely
to cater to the load of his premises. This low tension switch board shall be installed in a room adjacent to the sub-
station. All civil works, ventilation and fire protection within the sub-station shall be to the requirements and
approval of the Ministry of Electricity and Water.

405 The electrical installations in every building shall be adequately controlled by switchgear located adjacent to
the service intake and which is readily accessible to the consumer. The switchgear shall form an integral part of the
low tension switchboard of the building and shall be completely enclosed in metal or approved insulating material.
This switchgear shall incorporate means of isolation, means of excess current protection and means of earth leakage
protection.

NOTES - 1. For reasons of selectivity, means of earth leakage protection may be sub divided and
provided on the various outgoing feeders from the switchgear. In this event earth leakage
protection on the incoming switchgear may be omitted.

2. The switchgear shall not be installed in store, kitchen, bathroom/toilets, above sinks and
below staircase having less than 2 metres of vertical distance between floor and the
celling.

406 In single occupancy buildings, the switchgear detailed in Clause 405 shall also be the consumers main means
of isolation and provision for installing the MEW‟s service cabinet or cable cut-out and Kilo-watt-hour-meter shall
be allowed immediately preceding the switchgear. The service cabinet shall be installed on the outside of the front
boundary wall of the premises.

NOTE - The Kilo-watt-hour-meter may be integrated into the low tension switchboard of the building.

407 In multi-occupancy buildings, the switchgear detailed in Clause 405 shall be considered only as a means of
isolating the electricity supply from the entire building in the event of an emergency and separate means of isolating
the electrical supply of each individual consumer shall be provided. Such m eans of isolation shall incorporate
separate means of excess current and earth leakage protection and shall be located at a position which is fully under
the control of the consumer.

NOTES - 1. In multi-occupancy buildings proper selection of both excess current and earth leakage protection is
essential in order to ensure discrimination in the operation of these protective devices.

2. In multi-occupancy buildings, the requirements of a separate means of earth leakage protection as
set out in Clauses 405 and 412 may be omitted. Provided each individual consumer's switchgear is
equipped with such protection and all metal works are bonded.
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408 The means of isolation provided for individual consumers in a multi-occupancy building may be combined
together and installed adjacent to the service intake provided facilities are available for pad- locking and sealing
each individual means of isolation in the OFF position. Where such means of isolation is provided additional
isolation within the consumer's premises shall also be available.

409 Adequate space shall be provided adjacent to the consumer's switchgear to install Ministry of Electricity and
Water's cable cut-out and cable. The overall dimensions of Ministry of Electricity and Water's standard cable cut-
outs and the minimum distance between the bottom of the cut-out and the floor level shall be as indicated below.
The cable entry duct shall be laid at a depth of 750 mm below ground level and terminated immediately below the
space demarcated for the cut-out in a manhole of ample dimensions.

Size of
Cut-out
Amp


aaaa
Height
mm
Width
mm
Depth
mm
Minimum distance between
bottom of cut-out and floor mm
100 375 400 150 1000
160 600 400 150 1000
200 600 400 150 1000
250 600 400 150 1000
300 730 400 150 1000

410 The means of isolation shall be by a load break switch or circuit breaker arranged to disconnect all the live
conductors only and equipped with an isolating link on the neutral conductor.

411 The excess current protection shall be either by means of fuses or over-current releases fitted in each live
conductor. The rating of the excess current and isolation devices shall be determined in accordance with the total
connected load.

NOTE -