Page 54 - RotF - Electrical Specification_Neat

GENERAL ELECTRICAL SPECIFICATION
Version 2014-2

(with amendments). XLPE insulated, extruded PVC, bedded, armoured, LSF sheathed
cables shall conform to BS 5467 1997 (with amendments)

Cables shall comprise stranded copper conductors with galvanised steel wire armour. As
indicated above, cables with extruded PVC bedding shall be used.

Cable glands, shall comply with BS 6121: 1989 and shall be provided complete with PVC
cable shrouds and brass earth tags. All glands shall be ‘CW’ type with an outer seal for
internal and external use.
2.8.2.2 Installation

Cables shall be installed in accordance with the requirements of BS 6346, BS 5467 and the
manufactures recommendations.

Cables shall be delivered to site and stored on a cable drum with the manufacturers label
attached.
Cables shall be fixed to cable trays, the building fabric/structure, laid in trenches and
installed in ducts as detailed on the drawings.

Cables shall be supported using claw cleats at centres not exceeding those detailed in BS
7671.

The minimum internal bending radius of the cables shall not be less than those detailed in
BS 7671.

The current ratings of cables have been based upon:
a. Single layer of cables on perforated trays touching.
b. Buried at 600mm below ground level not bunched.

Cables shall be installed only using these methods i.e. stacking of cables will not be
permitted.

To facilitate the installation of cables the drums shall be supported by either Jack stands
or a drum cradle to allow the cable to rotate freely whilst the cable is drawn through
ducts laid in trenches or on cable trays.

The Electrical Contractor’s attention is drawn to the need to observe the warning provide
in BS 5467 & BS 6346, which relate to the cables being installed during periods of low
temperature, which states “to avoid damage during handling, the cable shall only be
o
installed when both the cable and the ambient temperatures are above 0nd have
C a
been so for the previous twenty four hours, or where special precautions have been taken
to maintain the cable above the temperature”.

Once all cables have been drawn into ducts, all holes shall be sealed by a waterproof
sealing compound to prevent the ingress of water, vermin etc. Drawpits to be sealed with
lean mix sand and cement.
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