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, MCB 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.
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.
Also known as a fusebox, 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.
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.
Electrical Installation Condition Report – formerly called PIR. A report to establish the overall condition of all the electrics in a building, stating whether it is satisfactory for continued use, detailing any work that might need to be done.
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.
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.
Milliamp or 1/1000 part of an amp
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.
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 most domestic electrical work to be carried out by government-registered electricians, or to be inspected by Building Control officers.
PAT – Portable Appliance Testing
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 £120, 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.
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
The value of overcurrent at a given point in a circuit resulting from a fault between live conductors.
RCD – Residual current device
Residual current device is a safety device that switches off the electricity automatically when it detects an earth fault, providing protection against electric shock.
Ring final circuit/ring main/ ring
A final circuit connected in the form of a ring and connected to a single point of supply.
What is earthing?
Metal parts of an electrical installation or appliance may become live if there’s a fault. The purpose of earthing is to minimize the risk of electric shock should anyone touch those metal parts when a fault is present. This is achieved by providing a path for fault current to flow safely to earth, which also causes the protective device to disconnect the circuit, removing the danger.
What is main equipotential bonding?
The purpose of main equipotential bonding is to minimize the risk of electric shock to anyone who may be touching two separate conductive parts when a fault occurs somewhere in the supply or in the electrical installation. This is achieved by connecting bonding conductors between particular points to minimize the voltage that may be created between them under fault conditions.