SECTION 2:DEFINITIONS

 SECTION 2

DEFINITIONS

Accessory.  A Device other than current-using equipment associated with such equipment or with the wiring of an installation.

Adapter, Socket outlet.  An accessory for insertion into a socket outlet and containing metal contacts to which may be fitted one or more plugs for the purpose of connecting to the supply, the lighting fittings or current using appliances.

Ambient temperature.  The temperature of the air or other medium where the equipment is to be used.

Appliance.  An item of current-using equipment other than a luminaire or an independent motor.

Barrier.  A part providing a defined degree of protection against contact with live parts, from any usual direction of access.

Bonding.  Electrical connection putting the various exposed conductive parts at a common potential.

Bunched.  Cables are said to be bunched when two or more are contained within a single conduit, duct, ducting, or trunking or, if not enclosed, are not separated from each other.

Cable coupler.  A means enabling the connections at will, of two flexible cables. It consists of a connecter and a plug.

Caravan.  Any structure designed or adapted for human habitation which is capable of being moved from one place to another.

Circuit breaker.  A mechanical switching device capable of making, carrying and breaking currents under normal circuit conditions and also of making, carrying for a specified time, and breaking currents under specified abnormal circuit conditions such as those of short circuit.

NOTE A circuit breaker is usually intended to operate infrequently, although some types are suitable for frequent operation.

Circuit conductor.  A current carrying conductor forming part of a circuit or final circuit, but excluding the earth continuity conductor.

Connector.  A device intended for connection to a Flexible cord or flexible cable which has protected current carrying contact tubes similar to those of a socket outlet.

Consumer's installation.  Wiring and apparatus situated upon the consumer’s premises and controlled or/and installed by him, excluding any switchgear of the supply undertaking.

Consumer's Terminals.  The point in the consumers installation at which the incoming supply of energy is delivered to that installation.

Current-carrying capacity of a conductor.  The maximum current which can be carried by a conductor under specified conditions without its steady state temperature exceeding a specified value.

Damp and Dust-proof.  Applied to apparatus and accessories to denote that the live and other component parts are protected by an enclosure or enclosures being so protected and/or fitted as to prevent the ready ingress of dust and/or moisture.

Damp situation. A situation in which moisture is either permanently present or intermittently present to such an extent as to be likely to impair the effectiveness of an installation conforming to the requirements for ordinary situations.

Danger. Danger to health or danger to life or limb from shock, burn, or injury from mechanical movement to persons (and livestock where present), or from fire, attendant upon the use of electrical energy.

Distribution board.  An assemblage of parts including one or more fuses or circuit-breakers, arranged for the distribution of electrical energy to final circuits or to other distribution boards.

Duct.  A closed passage-way formed underground or in a structure and intended to receive one or more cables which may be drawn in.

Earth-continuity conductor.  The conductor including any clamps, connecting to the consumers earthing terminal, those parts of an installation which are required to be earthed. It may be in whole or in part the metal sheath and/or armouring of a cable, or the special earth continuity conductor of a cable or flexible cord incorporating such a conductor.

Earth electrode.  A metal rod or rods, or other conducting object, providing an effectual connection with the general mass of the earth.

Earthed.  Effectually connected to the general mass of the earth.

Earthing lead.  The final conductor by which the connection to the earth electrode, or other means of earthing, is made.

Electrode boiler (or electrode water heater).  Equipment for the electrical heating of water or electrolyte by the passage of an electric current between electrodes immersed in the water or electrolyte.

Electric discharge lamp.  An electric lamp comprising a hermetically sealed bulb or tube containing gas and/or metal intended to be vaporized during operation and fitted with electrodes between which a discharge of electricity takes place, the useful light being emitted either by the discharge through the gas or vapour or by the fluorescence of translucent coating which may be on the inner surface of the outer tube or bulb.

Emergency switching.  Rapid cutting off of electrical energy to remove any hazard to persons, livestock, or property which may occur unexpectedly.

Enclosure.  A part providing an appropriate degree of protection of equipment against certain external influences and a defined degree of protection against contact with live parts from any direction.

Excess current protection.  Excess current protection which will operate within four hours at 1.45 times the designed load current of the circuit which it protects.

Final circuit.  An outgoing circuit connected to a distribution board or otherwise and intended to supply electrical energy to current using apparatus either directly or through socket-outlets or fused spur boxes.

Fixed equipment.  Equipment fastened to a support or otherwise secured in a specific location.
Fuse element.  A part of a fuse designed to melt when the fuse operates.

Fuse link.  Apart of a fuse, including the fuse element(s), which requires replacement by a new fuse link after the fuse has operated and before the fuse is put back into service.

Insulation.  Suitable non-conducting material enclosing, surrounding or supporting a conductor.

Isolator.  A mechanical device capable of opening or closing a circuit under conditions of no load or negligible current.

Live.  In relation to a conductor means that under working conditions and a difference of voltage exists between the conductor and earth.

Neutral conductor.  The neutral conductor of a three phase 4-wire system, the conductor of a single phase installation which is earthed by the Electricity Distribution Directorate.

Occupancy single.  A single occupancy building is one which is normally occupied by one consumer only and is provided with one kilo-watt-hour meter at each intake.

NOTE: Buildings and premises which have only one kilo-watt-hour meter but are occupied by different tenants will not be considered as a single occupancy.

EXCEPTION Residential hotels and other similar resorts will be considered as single occupancy buildings with one or more kilo-watt-hour meters to the same consumer.

Occupancy-multi.  A multi-occupancy building is one which is occupied by more than one tenant and is provided with one or more kilo-watt-hour meters.

Phase conductor.  A conductor of an A/C system for the transmission of electrical energy, other than a neutral conductor.

Plug.  A device, provided with contact pins, which is intended to be attached to a flexible cable, and which can be engaged with a socket outlet or with a connector.

Point (in wiring).  A termination of the fixed wiring intended for the connection of current-using equipment.

Portable equipment.  Equipment which is moved while in operation or which can easily be moved from one place to another while connected to the supply.

Ring circuit.  A final circuit arranged in the form of a ring and connected to a single point of supply.

Socket outlet.  A device, provided with female contacts, which is intended to be installed with the fixed wiring and intended to receive a plug.

NOTE: A luminaire track system is not regarded as a socket outlet.

Space factor.  The ratio (expressed as percentage) of the sum of the overall cross-sectional areas of cables (including insulation and any sheath) to the internal cross-sectional area of the conduit or other cable enclosure in which they are installed.  The effective over-all cross-sectional areas of a non-circular cable is taken as that of a circle of diameter equal to the major axis of the cable.

Spur: A branch cable connected to a ring circuit.

Stationary equipment.  Equipment which is either fixed, or equipment having a mass exceeding 18 kg and not provided with a carrying handle.

Switch.  A mechanical switching device capable of making, carrying and breaking current under normal circuit conditions, which may include specified operating overload conditions, and also of carrying for a specified time currents under specified abnormal circuit conditions such as those of short circuit.

NOTE: A switch may also be capable of making, but not breaking, short circuit currents.

Switch, linked.  A switch the contacts of which are so arranged as to make or break all poles simultaneously or in a definite sequence.

Switchboard. An assembly of switchgear with or without instruments, but the term does not apply  to a group of  local switches in a final circuit.

Switchgear. An assembly of main and auxiliary switching apparatus for operation, regulation, protection or other control of electrical installations.

Trunking.  A system of enclosures for the protection of cables, normally of square or rectangular cross section, of which one side is removable or hinged.

Voltage nominal.  Voltage by which an installation (or part of an installation) is designated. The following, ranges of nominal voltage (r.m.s. values for a.c.) are defined

Extra low.  Normally not exceeding 50V a.c. whether between conductors or to Earth.

Low.  Normally exceeding extra-low voltage but not exceeding 1000V  a.c. between conductors, or 600V a.c. between conductors and Earth.

NOTE : The actual voltage of the installation may differ from the nominal value by a quantity within normal tolerances.