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Do you speak sparky?
Whether your whole house is being rewired or you’re just having some new sockets fitted, it helps to know the difference between a consumer unit and a circuit breaker. To help you understand what your electrician is talking about, we’ve put together a jargon buster to explain below some of the more common terms used.
Accessory
Switches, sockets, ceiling roses etc.
British Standard BS 7671
Also known as the IEE (Institute of Electrical Engineering) wiring regulations. Details the requirements for electrical installations and is the standard against which all NICEIC contractors are assessed. To enrol with NICEIC all electricians, and anyone they employ, must meet this national safety standard.
Capping
A thin metal or plastic shaped channel sometimes used to contain cables when fixed to a wall before plastering. Capping is used to make it easy to run several cables following the same route with the minimum use of fixings. It does not provide protection against damage from nails or screws.
Certificate
Any electrician installing a new electrical installation (including a single circuit), altering, extending or adapting an existing circuit should issue the homeowner with electrical installation certificate or minor electrical installation works certificate to confirm the work complies with the requirements of BS 7671.
Circuit
An assembly of electrical equipment (socket outlets, lighting points and switches) supplied from the same origin and protected against over current by the same protective device(s).
Circuit-breaker or RCD
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. It is usually required to operate infrequently although some types are suitable for frequent operation.
Chasing
Making slots or grooves into walls in order to allow the installation of cables or wiring systems. Chasing causes a lot of disruption, noise and dust and once completed will require making good (see Making good). In Scotland, chases are known as raggles.
Class I equipment
Equipment in which protection against electric shock does not rely on basic insulation only, but which includes means for the connection of exposed-conductive-parts to a protective conductor in the fixed wiring of the installation. Class I equipment has exposed metallic parts, e.g. the metallic enclosure of washing machine.
Class II equipment
Class II equipment, such as music systems, television and video players, in which protection against electric shock does not rely on basic insulation only, but in which additional safety precautions such as supplementary insulation are provided, there being no provision for the connection of exposed metalwork of the equipment to a protective conductor, and no reliance upon precautions to be taken in the fixed wiring of the installation.
Class III equipment
Equipment, for example for medical use, in which protection against electric shock relies on supply at SELV (Safety extra low voltage) and in which voltages higher than those of SELV are not generated. Class III equipment must be supplied from a safety isolating transformer.
Consumer unit
Also known as a fuse box, consumer control unit or electricity control unit. A particular type of distribution board comprising a 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 of one or more fuses, circuit-breakers, residual current operated devices or signalling and other devices purposely manufactured for such use.
Distribution board
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 protective circuit conductors. It may also include signalling and other control devices. Means of isolation may be included in the board or may be provided separately.
Earthing
The purpose of earthing is to minimise the risk of receiving an electric shock if touching metal parts when a fault is present. This is achieved by providing a path for fault current to flow safely to earth, which would also cause the protective device (MCB, fuses) to disconnect the circuit removing the danger. The electrician will check that the earthing and bonding is satisfactory before starting any work.
Electrical installation certificate
A safety certificate issued by the electrician on completion of a new electrical installation, or changes to an existing electrical installation. The certificate confirms that the installation has been designed, built, inspected and tested to the UK national standard BS 7671.
Electrical installation
Any assembly of electrical equipment supplied by a common source to fulfil a specific purpose.
Electrical Safety Regulations
NICEIC registered electricians have already helped to improve the standard of electrical work in the UK. A new electrical safety law, often referred to as Part P of the Building Regulations, has further enhanced the protection of homeowners and reduced the risk of electric shock when using electricity. The law, which applies to England and Wales aims to improve electrical safety in the home and prevent the number of accidents, which are caused by faulty electrical work. The law requires an electrician registered with a government-approved scheme, such as NICEIC, to carry out most electrical work in the home. After completion of any work your NICEIC registered electrician will issue you with a Building Regulations Compliance Certificate to prove it meets the required standards of Part P. You can only carry out electrical work yourself if you can inspect and test that it is safe for use. To comply with the law you must notify your local building control office before you begin any work and pay the appropriate fee for them to inspect the work.
Extension leads
An extension cable, also known as a power extender, extension cord or an extension lead, is a length of flexible electrical power cable or flex with a plug on one end and one or more sockets on the other end - usually of the same type as the plug. However use of extension leads should be avoided where possible, as there is a chance of overloading the circuit.
Flush fitted
Electrical accessories such as switches or sockets installed so that their back boxes are contained in a wall, floor or ceiling and only the front plates are visible. Flush fitting is more aesthetically pleasing but usually involves chasing (see Chasing).
Fusebox
See consumer unit
Fused connection unit
Enables electricity to be supplied to an item of equipment or appliance providing its own method of circuit protection (by fuse), and sometimes includes a switch. Fused connection units are sometimes referred to in the electrical trade as fused spurs (see Spur).
LV
Low Voltage
MA
Milliamp or 1/1000 part of an amp
Main bonding
Connecting metal pipes (gas, water or oil) entering premises to the main earthing terminal of the electrical installation via low resistance conductors.
Making good
Restoring the finish of a wall or ceiling that has been damaged and replacing floorboards which have been lifted during the electrical installation work. Usually does not cover full redecoration, but will be the filling in of chases (see Chasing) and holes. You may agree with the electrician to leave the making good of walls and ceilings to another person such as a plasterer.
MCB
Miniature circuit-breaker (commonly known as a circuit-breaker). An automatic protective device fitted in the consumer unit which will disconnect a circuit if there is a fault or overload.
Mini trunking
A plastic enclosure having one removable side that is used to install cables on the surface of walls and ceilings.
Minor works certificate
A safety certificate (see Electrical installation certificate) used when only an addition or alteration is made to an electrical installation and no new circuits have been added.
Overcurrent
Electrical current (in amps) that exceeds the maximum limit of a circuit. May result in risk of fire or shock from insulation damaged from heat generated by overcurrent condition.
Partial rewire
A common situation where it has not been possible or necessary to fully rewire (see Rewire) the electrical installation. For example when cabling has been confirmed as being suitable for continued use to minimise the degree of damage and disruption to the decoration. Or where only a part of an installation has suffered damage from a burst water pipe or similar. If you are considering a partial rewire or it is offered to you as an option by an electrician it is very important that you agree and understand exactly what work is and is not being done before the work starts.
Part P
The specific section of the Building Regulations for England and Wales which relates to electrical installations in domestic properties.
Portable Appliance Testing (PAT)
Inspection and testing of electrical equipment including portable appliances, moveable equipment, hand held appliances, stationary equipment, fixed equipment/appliances, IT equipment and extension leads.
PIR - Periodic Inspection Report
An electrical survey, known as a Periodic Inspection Report (PIR) will reveal if electrical circuits are overloaded, find potential hazards in the installation, identify defective DIY work, highlight any lack of earthing or bonding and carry out tests on the fixed wiring of the installation. The cost of a typical PIR should start around £100, depending on the size of your property. The report will establish the overall condition of all the electrics and state whether it is satisfactory for continued use, and should detail any work that might need to be done.
PLI - Public Liability Insurance
Broad term for insurance which covers liability exposures for individuals and business owners. Homeowners should check that their electrician has public liability insurance, which covers them if someone is accidentally injured by them or their business operation. It will also cover them if they damage your property while on business. The cover should include any legal fees and expenses which result from any claim by you. Homeowners looking to employ trades people to undertake work on their homes should ensure the companies selected have suitable cover – minimum recommendation is £2 million.
Portable Equipment
Electrical equipment which is less than 18 kg in mass and is intended to be moved while in operation or which can easily be moved from one place to another, such as a toaster, food mixer, vacuum cleaner, fan heater.
Prospective Fault Current (PFC)
The value of overcurrent at a given point in a circuit resulting from a fault between live conductors.
RCD
Residual current device. This is a sensitive switching device that trips a circuit when an earth fault is detected. RCD protection is particularly important for socket circuits that may be used to supply portable equipment for use outdoors.
Rewire
The process of installing new cables, circuits and accessories and carrying out the inspection and testing before putting the installation into service. A full rewire should mean that all parts of the electrical installation are new. However you may wish for items such as switches and light fittings to be re-used and the electrician may wish to re-use a part of the installation which is electrically sound, due to it being difficult to remove and replace. It is very important that you agree and understand with the electrician exactly what work is, and is not, being done before the work starts (see Partial rewire).
Ring final circuit/ring main/ ring
A final circuit connected in the form of a ring and connected to a single point of supply.
SELV
Separated Extra-Low Voltage. An extra-low voltage system, which is electrically separated from Earth and from other systems in such a way that a single fault cannot give rise to the risk of electric shock
Spur
An additional connection often taken from an existing accessory such as a socket. It may provide a supply to a new socket or a fused connection unit (see Fused connection unit).
Supplementary bonding
The connecting together of the metal parts of electrical equipment (such as a heated towel rail) and the metal parts of a non-electrical item (such as pipes) to prevent a dangerous voltage between them, if a fault occurs. May be required in bath and shower rooms.
Surface mounted
This is where wiring or electrical accessories such as switches or sockets are installed so that they are on top of the surface or front of a wall, floor or ceiling. This causes less disruption to the decoration but is not as aesthetically pleasing as flush fitting (see Flush fitted).
Voltage, extra-low
Normally not exceeding 50 V a.c. or 120 V ripple-free d.c., whether between conductors or to earth.
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