Accessory: An electrical device or product including switches, sockets, adapters and connectors.

 

Alternating Current (AC): An electrical current that changes its direction of flow many times per second, used in mains electricity supplies.

 

Amp or Ampere (A): The single unit of electrical current.

 

Arc-Fault Circuit Interrupter (AFCI): A circuit breaker device used in the prevention of fires by detecting electrical arcs.

 

Blueprint: A set of comprehensive documents defining how a contractor or builder should work – including the electrical layout, floor plans, and full construction details.

 

Breaker Panel: Commonly found outside the home in a garage or basement, this is an electrical service panel containing circuit breakers that supply power to receptacle loads, lighting and heating.

 

Cartridge Fuse: A fuse, typically found in a ceramic tube topped and tailed with a metal contact cap, and available in a range of sizes and current ratings.

 

Circuit: A path in which electrons from a voltage or current source flow. The point where those electrons enter an electrical circuit is called the "source" of electrons. The point where the electrons leave an electrical circuit is called the "return" or "earth ground".

 

Circuit Breaker (CB): A device which automatically breaks an electrical circuit when a fault is detected.

 

Circuit Loading Factors: A set of criteria used to ensure you do not exceed the number of receptacles on a circuit.

 

Circuit Protective Conductor (CPC): Used to prevent metal components becoming ‘live’; otherwise referred to as the earth wire in a cable.

 

Circuit Tester (voltage tick): A device that plugs into a conventional outlet to test if a circuit is carrying standard voltage.

 

Compact Fluorescent Lamp (CFL): A type of energy-saving lamp.

 

Conductors: Any material, substance or device that allows the flow of electricity.

 

Conduit: Tubing, usually rigid metal or plastic, for protecting electric wiring.

 

Continuity Tester: A small, battery-operated device used to check that electrical circuits are complete.

 

De-Energized Circuit: A circuit with no power.

 

Direct Current (DC): An electrical current which flows in one direction, such as from a battery.

 

Distribution Circuit: A circuit supplying electricity to a secondary distribution board.

 

Double Pole (DP): A switch with two blades – allowing simultaneous opening or closing both sides of a circuit.

 

Earth Leakage Circuit Breaker (ELCB): A circuit protection device, available as voltage operated (now obsolete), or current operated (now called RCD).

 

Edison Screw (ES): a type of lamp base developed by Thomas Edison which literally screws into a lamp holder.

 

Electrical Installation Condition Report: A report detailing the condition of a property’s existing electrical installation.

 

Electrical Load: The part of an electrical system which actually uses energy or does the work needed.

 

Extra Low Voltage: A low supply of electricity, of 50V AC or less.

 

Floor Plan: A simple scaled drawing to depict rooms as seen from above.

 

Flush: The technique in which electrical accessories are sunk into the wall, so only the receptacle and cover-plate protrudes.

 

Fuse: A safety device which melts the wire inside it when an excessive current flows.

 

Fuse Box or Fuse Board: See ‘service panel’.

 

Fused Connection Unit (FCU): An electrical accessory containing a cartridge fuse, used to connect and protect an item of equipment.

 

Fused Spur Unit (FSU): See fused connection unit (FCU).

 

Ground Fault Circuit Interrupter (GFCI): A device used where electrical outlets are near a water supply, such as sinks or washing machines. A GFCI stops the flow of electricity by opening or breaking the circuit when a flow of current to ground is detected. Safety regulations require these to be installed before occupancy is permitted.

 

Ground Rod: A ½ inch in diameter and eight foot long copper or aluminum rod driven into the ground near the outside electrical service.

 

Grounding: The process of connecting equipment to a common ground or “earth”.

 

Hertz (Hz): Hertz is a unit of frequency (of change in state or cycle in a sound wave, alternating current, or other cyclical waveform) of one cycle per second. It replaces the earlier term of "cycle per second (cps)."

 

Home Run: The main line running from the electrical service panel to the first device in the electrical circuit.

 

Ingress Protection (IP): A rating system to show how protected an enclosure is against solids and liquids.

 

Insulation Resistance (IR): The measurement of how an electrical circuit or equipment is able to resist the leakage of electricity.

 

Light-Emitting Diode (LED): An energy-efficient device which emits light when supplied with electricity, developing rapidly into a viable light source in its own right.

 

Lineman’s Pliers: A tool used for cutting cable or heavy wire and twisting ends together.

 

Live: Electric wire or cable through which current is flowing, as opposed to ground wire or neutral wire. Also called hot wire.

 

Live Conductor: Wires with electrical current running through them.

National Electric Code (NEC): The NEC sets the foundation for electrical safety in residential, commercial, and industrial occupancies. This resource is updated annually and electricians must stay up to date with the latest codes and requirements.

 

Neutral Conductor: The conductor that, under normal conditions, will carry no current.

 

Long-Nose Pliers: A hand tool used to bend small loops at wire ends, or to cut off wires.

 

Low Voltage: An electrical supply of between 50V AC and 1000V AC.

 

Luminaire: A complete electric light unit (used especially in technical contexts).

 

Megger: A brand of electrical test equipment.

 

Miniature Circuit Breaker (MCB): A small circuit breaker used in service panels.

 

Neon Voltage Tester: A tool used to tell if wires are ‘hot’. The light indicates that the circuit is live.

 

Neutral (N): A wire connected to the neutral point of an electrical system (and usually also to earth).

 

Ohm: The unit of measure for electric resistance.

 

Overcurrent: A condition when the normal load current is exceeded in a circuit. This may result in an overload or a short circuit.

 

Overhead Wires: Wires that are found above the ground.

 

Overload: An overcurrent exceeding the normal full load current of a circuit.

 

Passive Infrared (PIR): A sensor, often used in alarm systems, used to detect movement of objects at a different temperature to their surroundings (usually people or animals).

 

Pig Tail: An electrical pigtail is a single piece of electrical wire that is used to connect two or more wires.

 

Radial Circuit: A circuit arranged so that the cable runs from the consumer unit or fuse box to one or more accessories or loads without returning to the origin.

 

Receptacle: A 110 volt or 220 volt device used to furnish an electrical source for electrically powered tools or appliances.

 

Recessed Lighting: A light fixture installed into a hollow opening, also known as ‘pot lights’.

 

Residual Current Circuit Breaker (RCCB): See residual current device (RCD).

 

Residual Current Circuit Breaker with Overcurrent Protection (RCBO): A device designed to protect a circuit, combining features of a circuit breaker and an RCD.

 

Residual Current Device (RCD):  A circuit protection device which detects the difference in current between live conductors and disconnects it if the differential current exceeds a specific value.

 

Resistance: The property of an electrical circuit, measured in ohms, that restricts the flow of current.

 

Resistive Load: Resistive loads typically convert energy into heat as a result of the electrical process moving from each component of the system to the next. The heat must then be expelled from the system through a medium such as air or water. This energy can be utilized purposely in heating devices.

 

Retro-fit: A customized or serviced piece of old technology to update it to current needs or requirements.

 

Semiconductor Fuses: A fuse used to protect solid-state devices such as a transistor.

 

Service Panel or Distribution Board: Also known as panelboard, breaker panel, or electric panel. It is a component of an electricity supply system that divides an electrical power feed into subsidiary circuits, while providing a protective fuse or circuit breaker for each circuit in a common enclosure.

 

Short Circuit: A short circuit is an electrical circuit that allows a current to travel along an unintended path with no or a very low electrical impedance. It is common to misuse "short circuit" to describe any electrical malfunction, regardless of the actual problem.

 

Short Circuit Rating: The maximum short circuit current an electrical component can sustain without excessive damage.

 

Spur: An electrical circuit supplying a socket or other accessory, which branches off a main circuit.

 

Steel Wire Armoured (SWA): A cable, suitable for use outdoors and underground, with a layer of steel wire strands around the central conductors.

 

Surface Mount: When the accessory is mounted to the surface of the wall.

 

Switch Leg:  The wire connected to the on-off switch.

 

Temporary Pole: A pole, consisting of a breaker box and receptacles, used to provide electrical power during a construction project.

 

Underground Cables: Buried wires under the ground.

 

Volt (V): A unit of electrical pressure.

 

Voltage Rating: The Rating of an electrical appliance indicates the voltage at which the appliance is designed to work and the current consumption at that voltage.

 

Watts: The energy consumed by a light bulb or appliance per second is expressed in watts.

 

Wire Nuts: Insulated connectors for exposed wires to link them and prevent electric shock.

 

Wire Stripper: A tool to remove the plastic, rubber or paper insulation around an electrical wire.