700 الأسلاك والكابلات

700 WIRES AND CABLES

700--1 Every cable for use as fixed wiring shall be selected from one of the following types:

i) 600/1000 Volts multi-core PVC insulated and PVC sheathed armoured and unarmoured cables.
ii) 600/1000 Volts multi-core XLPE insulated, PVC sheathed armoured and unarmoured cables.
iii) 600/1000 Volts multi-core silicone rubber insulted hard grade PVC sheath bonded to coated
aluminium foil cable with fire resistance and fire retardant properties.
iv) 600/1000 Volts single core PVC insulated and PVC sheathed armoured and unarmoured cables.
v) 600/1000 Volts single core XLPE insulated, PVC sheathed armoured and unarmoured cables.
vi) 600/1000 Volts and single core PVC or XLPE insulated and non-magnetic armoured cables.
vii) 600 Volts Mineral insulated cables.
viii) 450/750 Volts single core PVC insulated and sheathed cables.
ix) 450/750 Volts single core PVC insulated cables.
x) 450/750 Volts twin core and earth PVC insulated and sheathed cables.
xi) Other cables subject to the approval of M.E.W .
All cables except (i), (ii), (iv) and (v) shall have conductors of plain annealed copper. Cables (i), (ii), (iv) and (v)
may have conductors of aluminium or plain annealed copper. The PVC insulation employed shall be suitable for
the site conditions.

700--2 The maximum permissible drop in voltage from the consumer's terminals (Service Intake) to any
point in his installation shall not exceed 2.5% of the nominal voltage when the conductors are carrying full load
current (6 volts for single phase and 10 volts for 3 phase systems). When a project is having its own electrical
distribution substation, the maximum permissible drop in voltage from the substation to any point in the
installation shall not exceed 5% of the nominal voltage when the conductors are carrying full load current.

700--3 Sizes of single core and multi-core cables shall be such that current carried by them shall not exceed
those shown in the appropriate tables in Section 15.

700--4 Cables shall not generally be connected in parallel except where for a particular loading, a single cable is
insufficient and it is not practicable to employ bus bar trunking. In such situations single core or multi -core
cables may be connected in parallel provided that the cables are of the same type, size and length to ensure
proper division of the current.

700--5 Identification of wires and cables

(a) Single core, PVC insulated, non-armoured cables used for wiring shall be identified by the
following colours:

Phase
Neutral
Earth
Red
Black
Green/Yellow





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(b) The conductors of multi-core PVC insulated armoured and non-armoured cables shall be identified by the
following colours:

Two-core cable
Three-core cable
Four-core cable
Red, Black
Red, Yellow, Blue or Red, Black, Green/Yellow
Red, Yellow, Blue and Black.

(c) All wires or conductors of cables connected to the neutral of the supply shall have "BLACK" outer layer of
insulation and shall not be used as phase conductor. Similarly, Green/Yello w coloured wires or conductors
of cables shall be used as "EARTH" conductor only.

700--6 All conductors and cables shall be adequately protected against any risk of mechanical damage to which
they may be liable in normal conditions of service.

700--7 Cables shall not be run in a lift shaft unless they form a part of the lift installation. Cabl es of lift
installations other than travelling cables in such a shaft shall be protected from mechanical damage and shall be
armoured or mineral insulated cables or enclosed in metal conduits.

700--8 The different cables specified in Clause 700 -1 shall be installed in the manner indicated below:

(a) Multi-core and single core PVC or XLPE insulated, armoured and PVC sheathed cables may be directly
buried in the ground, laid in trenches and trays or drawn through ducts.
The maximum current carried by any cable will depend upon the worst conditions of installation.

(b) Multi-core and single core PVC or XLPE insulated, non-armoured and PVC sheathed cables may be
installed in cable trays and in trenches or fixed to the walls by cleats.
These cables shall only be installed at locations where they will not be damaged.

(c) Single core PVC insulated cables shall only be run in conduits or in trunking.

(d) Twin core and earth PVC insulated and PVC sheathed cables may be run on wooden battens fixed to the
walls or may be installed within metallic partitions provided always that they are not liable to damage.

(e) Mineral insulated cables may be installed at locations where flame-proof installations are necessary or at
locations of high temperature and elsewhere as required.

NOTE - The ends of mineral insulated metal sheathed cables shall be protected from moisture by being suitably
sealed and the insulation shall be thoroughly dry before the sealing material is applied. Such sealing
material, and any material used to insulate the conductors where they emerge from the insulation
shall have adequate insulating and moisture-proofing properties, and shall retain these properties
throughout the range of temperatures to which the cable is subject in service.

(f) Multi-core silicone rubber insulated PVC sheath bonded to coated aluminium foil cable with fire
resistant and retardant properties may be employed where flame proof installations are necessary, or at
locations of high temperature or for emergency and fire alarms circuits and elsewhere as required.

(g) Single core PVC or XLPE insulated and non-magnetic armoured cables may be installed in cable trays,
trenches and ducts or fitted to the walls by cleats. At all locations they shall be protected from
mechanical damage.

(h) Single core PVC insulated and sheathed cables may be installed in cable trays.