BS 8488-1:2009 pdf free download – Prefabricated wiring systems intended for permanent connection in fixed installations Part 1 – Specification.
6.2.4 Prefabricated wiring systems shall incorporate installation couplers with a voltage rating and current rating of not less than the rating of the prefabricated wiring system.
6.3 Connectable conductors
Prefabricated wiring systems shall provide a means of connection to the supply or other equipment by either a suitable connector or a lead with free ends.
7 Wiring
7.1 Supply connection and other wiring
7.1.1 The cross-sectional area of the cable conductors shall be compatible with the rated current of the wiring system.
7.1.2 Only cable manufactured in accordance with or conforming to a BS or 85 EN shall be used for the wiring of a prefabricated wiring system.
7.1.3 Cable with identification colours green and yellow shall be used for earth connections (circuit protective conductors) only.
7.1.4 When checked by visual inspection and tested in accordance with the continuity tests in C.2, prefabricated wiring systems shall be so constructed that electrical connection shall be permanently and reliably connected from the supply connection to the final connector of the system.
8 Provision for earthing
COMMENTARY ON CLAUSE 8
Metal encased prefabricated wiring systems may have two separate earth paths in a section, one being the circuit protective conductor within the wiring system and the other being a supplementary protective bonding conductor external to the wiring system.
8.1 When checked by visual inspection and tested in accordance with the continuity tests in C.2, the circuit protective conductor within the wiring system shall be permanently and reliably connected to an earthing terminal or earthing contact.
8.2 When checked by visual inspection, metal parts of metal encased prefabricated wiring systems which are accessible when installed or which might become live in the event of an insulation fault, shall be permanently and reliably connected to an earthing terminal or earthing contact.
NOTE Metal parts screened from live parts by metal parts which are connected to the earthing terminal or earthing contact, and metal parts separated from live parts by double insulation or by reinforced insulation, are not for the purpose of this requiremenz, regarded as likely to become live in the event of an insulation fault.
8.3 When tested in accordance with C.3, the earthing connections shall be of low resistance (i.e. resistance not greater than 0.5
8.4 When checked by inspection and by attempting to loosen the clamping means by hand, earthing terminals shall be adequately locked against accidental loosening. For screw terminals, it shall not be possible to loosen the clamping means by hand. For screwless terminals, it shall not be possible to loosen the clamping means unintentionally.
8.5 When checked by inspection and if necessary by inspection of material data sheets, earthing terminals of prefabricated wiring systems shall be such that the risk of corrosion resulting from contact between these parts and the copper of the earthing conductor, or any other metal that is in contact with these parts, is minimized.
The body of the earthing terminals shall be of brass or other metal no less resistant to corrosion, unless it is part of the metal frame or enclosure, in which case the clamping means shall be of brass or other metal no less resistant to corrosion.
8.6 For metal encased prefabricated wiring systems, when checked by visual inspection, the arrangement of the terminations between sections shall be such that the cables become taut or metal encasement reaches the limit of adjustment before any strain is placed on the earth connection or conductor.