Understanding your electrician - jargon buster
(Descriptions gratefully taken from BS 7671:2008 and the NICEIC web-site)
A device, other than current-using equipment, associated with such equipment or with the wiring of an installation.
BS - BRITISH STANDARD;
British standard BS 7671 - also known as the IEE (institute of electrical engineering) wiring regulations. Details the requirements for electrical installations.
A closed enclosure normally of rectangular cross-section, of which one side is removeable or hinged, used for the protection of cables and for the accommodation of other electrical equipment.
Any electrician installing a new electrical installation (including a single circuit), altering, extending or adapting an existing circuit should issue the homeowner with an electrical installation certificate or a minor electrical installation works certificate, so confirming that the works comply with BS 7671.
An assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s).
A device capable of making, carrying and breaking normal load currents and also making and automatically breaking, under pre-determined conditions, abnormal currents such as short-circuit currents. Normally required to operate infrequently.
CIRCUIT PROTECTIVE CONDUCTOR (cpc;
A protective conductor connecting exposed-conductive parts of equipment to the main earth terminal.
CONSUMER UNIT; (commonly called a fuse box)
A particulat type of distribution board comprising a type-tested co-ordinated assembly for the control and distribution of electrical energy, principally in domestic premises, incorporating manual means of double-pole isolation on the incoming circuit(s) and an assembly for one or more fuses, circuit-breakers, residual current operated devices or signalling and other devices proven during the type-test of the assembly as suitable for such use.
Equipment which converts electrical energy into another form of energy, such as light, heat or motive power.
An assembly containing switching or protective devices (e.g. fuses, circuit-breakers, residual current operated devices) associated with one or more outgoing circuits fed from one or more incoming circuits, together with terminals for the neutral and circuit protective conductors. It may also include signalling and other control devices. Means of isolation may be included in the board or may be provided seperately.
The conductive mass of the earth, whose electric potential at any point is conventially taken as zero.
Connection of the exposed-conductive parts of an installation to the main earth terminal of that installation.
An assembly of associated electrical equipment having co-ordinated characteristics to fulfil specific purposes.
FUSED CONNECTION UNIT;
A device associated with the fixed wiring of an installation by which appliances may be connected, and having provision for a replaceable cartridge fuse link.
Milliamp or 1/1000 part of an amp.
MAIN EARTHING TERMINAL;
The terminal or bar provided for the connection of protective conductors, including protective bonding conductors, and conductors for functional earthing, if any, to the means of earthing.
Electrical current (in amps) that exceeds the maximum limit of a circuit. May result in risk of fir or shock from insulation damaged from heat generated by overcurrent condition.
The specific section of the building regulations for England and wales that relates to electrical installations in domestic properties. Part P provides safety regulations to protect householders, and requires certain domestic electrical installation work to be carried out by government-registered electricians, or to be inspected by Building Control Officers.
PROSPECTIVE FAULT CURRENT;
The value of overcurrent at a given point in a circuit resulting from a fault between live conductors.
RESIDUAL CURRENT DEVICE (RCD);
The RCD is a safety device that switches of the electricity automatically when it detects an earth fault, providing protection against electric shock and fire.
RING FINAL CIRCUIT;
A final circuit arranged in the form of a ring and connected to a single point of supply.
A branch from a ring or radial circuit.