Here you will find a glossary of common electrical abbreviations, this list is in now way exhaustive


All electrical pages are for information only! New rules have been introduced for electrical safety in the home, please read this document by clicking here, before starting any electrical work


Before working on any electrical circuit you must ensure that it is isolated correctly and cannot accidentally be switched back on. Please read the article on safe isolation procedures before doing any electrical work. If you are not 100% certain what you are doing call a qualified electrician. Building regulations are changing all the time and modifying your home electrics could be against new rules and could invalidate your home insurance, if in doubt check first!


AMP - Ampere The unit of measurement of electric current. It is proportional to the quantity of electrons flowing through a conductor past a given point in one second. It is analogous to cubic feet of water flowing per second.

BASEC- British Approvals Services for Cables. You will often see BASEC approved on the pvc covering of today's modern cable.

CCT - circuit- Any combination of wiring and components that provides a path for the flow of electricity.

CCU - Cooker control unit- This is normally a two pole switch that is located within 2 metres of an electric cooker, sometimes these switches also incorporate a socket outlet.

CPC - Circuit Protective conductor- a system of conductors joining together all exposed conductive parts and connecting them to the main earthing terminal.

CU - Consumer unit - A consumer unit is a box of fuses or MCB's which are normally arranged in a single row. A consumer unit will normally be located near to where the main electricity supply enters the home.

DIN- Deutsche Industrie Norm A DIN rail is a standardized 35 mm wide metal rail with hat-shaped cross section. It is widely used, especially in Europe, for mounting circuit breakers and industrial control equipment inside equipment racks.

EEBADS- Earthed Equipotential Bonding and Automatic Disconnection of Supply

ELV - Extra low voltage- Voltage that is below 50 Volts AC

FCU - Fused connection unit- Fcu's are used to connect appliances directly to an electrical circuit, such as a cooker hood or another appliance that is permanently fixed and is not normally removable.

FELV - Functional Extra low voltage-any other extra low voltage circuit that does not fulfil the requirements for an SELV or PELV circuit. Although the FELV part of a circuit uses an extra low voltage, it is not adequately protected from accidental contact with higher voltages in other parts of the circuit. Therefore the protection requirements for the higher voltage have to be applied to the entire circuit.

IEE- INSTITUTE OF ELECTRICAL ENGINEERS- Founded in 1871, the IEE is the largest professional engineering society in Europe and has a worldwide membership of 120,000.

KW- Kilowatt One thousand watts of electricity. Ten 100-watt light bulbs use one kilowatt of electrical power.

KW/h- One kW of electrical power used for one hour. The most common measurement of electrical consumption, most grid connected electrical meters measure kW / h for billing purposes.

LV - Low voltage 50 -1000 Volts AC

MCB- Miniature Circuit Breaker is an electrical circuit protection device used as an alternative to re-wireable and cartridge type fuses. It trips out when too much current flows in the circuit, typically under fault conditions.

MCCB - Moulded case circuit breaker

MD - Maximum demand- is the largest current normally carried by circuits, switches and protective devices.

MICC - Mineral insulated copper cable- Often caller Pyro, this cable is insulated using inorganic minerals, often Magnesium Oxide. It is very resistant to heat, corrosion and UV light. This kind of cable is often used to wire fire alarms.

NICEIC- National Inspection Council for Electrical Installation Contracting. The NICEIC is the UK's consumer safety organisation and independent regulatory body for the electrical industry.

PAT- Portable appliance testing - testing of portable appliances to ensure that they are electrically safe to use.

PELV- Protected extra low voltage- In contrast to an SELV circuit, a Protected Extra Low Voltage (PELV) circuit has a protective earth (ground) connection. A PELV circuit, just as with SELV, requires a design that guarantees a low risk of accidental contact with a higher voltage. For a transformer, this can mean that the primary and secondary windings must be separated by an extra insulation barrier or by a conductive shield with a protective earth connection.

RCBO - Residual circuit breaker with built in overload protection- Combines earth leakage protection, overload and short circuit protection. Some of these take up two spaces in consumer units!

RCCB - Residual current circuit breaker- this constantly measures the electricity flowing through the live and neutral conductors, if it detects an imbalance it will immediately disconnect the supply, normally within 30ms.

SELV - Separated extra low voltage- This should be safely separated from other circuits that carry higher voltages and isolated from earth (ground) and from the protective earth conductors of other circuits.

VD- Volt drop- a voltage drop in a circuit normally occurs when current is passed through a circuit. The greater the resistance of the circuit the greater the volt drop.

VOLT- A unit of measure of the pressure in an electrical circuit. Volts are a measure of electric potential. Voltage is often explained using a liquid analogy -- comparing water pressure to voltage: a high pressure hose would be considered high voltage, while a slow-moving stream could be compared to low voltage.

WATT HOUR- Electrical power measured in terms of time. One watt hour of electricity is equal to one watt of power being consumed for one hour. (A one-watt light operated for one hour would consume one watt hour of electricity.)