Electrical jargon explained: an A to Z for UK sparkies 

Electrical terms can feel like code at first. This plain-English A to Z keeps things simple, UK-specific, and exam friendly. If you are just starting out, build your f oundation with c&g 2365 or the full level 2 electrician course at Elec Training. Curious about earnings and industry pay frameworks while you learn, see our average electrician salary guide and current JIB rates overview. 

A 

AC, Alternating Current: Current that periodically reverses direction. Standard for UK mains. 
Ampere, A: Unit of electric current, the rate of flow of charge. 
Ammeter: Meter that measures current in amperes, connected in series. 
Arc flash: A high-energy discharge across an air gap that can generate extreme heat and light. Serious hazard, strict PPE and procedures apply. 

B 

Bonding: Connecting extraneous conductive parts to the main earthing terminal to reduce touch voltage. 
BS 7671: UK Wiring Regulations covering design, erection, and verification of electrical installations. 

C 

Circuit: A complete path for current flow. 
Circuit breaker, MCB: Automatic protective device that trips on overcurrent or short circuit. 
Conductor: Material that allows current to flow with low resistance. 
Conduit: Protective tube, metal or plastic, for routing cables. 
Consumer unit, CU: Distribution board in premises that houses main switch and protective devices. 
CPC, circuit protective conductor: The protective conductor for a circuit. 
Capping: Thin channel used to tidy surface cable routes before plastering. 
Chasing: Cutting a groove in masonry to recess cables. 
Current: Flow of electrons measured in amperes. 

D 

DC, Direct Current: Current flowing in one direction, for example from a battery. 
Double insulated: Appliance design that does not require an earth due to two layers of insulation. 
Double-pole switch: Isolates both line and neutral conductors together. 
Distribution board: Another term for consumer unit or sub-board. 

E 

Earth: Reference point and safety connection to the general mass of earth. 
Earthing: Connecting exposed conductive parts to earth so protective devices operate on a fault. 
EIC, Electrical Installation Certificate: Confirms new work complies with BS 7671. 
EICR, Electrical Installation Condition Report: Periodic report on the condition of an existing installation. 

F 

Flex: Flexible cable for portable or movable equipment. 
Fuse: Sacrificial overcurrent device with a calibrated element. 
Fused connection unit, FCU: Accessory with a replaceable fuse to supply an appliance or spur. 

G 

Ground: Often used interchangeably with earth, in the UK we say earth more commonly. 

H 

Hot: Colloquial for live or energised conductor. 

I 

Insulation: Non-conductive material around conductors. 
Insulation resistance: Test value indicating the integrity of insulation between conductors. 
Inverter: Converts DC to AC, used in PV and backup systems. 

J 

Junction box: Enclosure for terminating and joining c onductors. 

K 

Kilowatt, kW: 1,000 watts, a unit of power. 
Kilowatt-hour, kWh: Energy unit, one kW used for one hour. 

L 

Live, line: The energized conductor that supplies voltage to a circuit. 
Load: Any device that consumes electrical power. 
Loop: Method of wiring so supply continues to the next point in the circuit. 

M 

MCB, miniature circuit breaker: Resettable overcurrent device for final circuits. 
Megger: Common brand name used generically for an insulation resistance tester. 
Main bonding: Bonding of incoming services like gas and water to the main earthing terminal. 
Mini trunking: Small plastic trunking for surface cable routes. 
Minor Works Certificate: Certificate for small additions or alterations that do not include a new circuit. 

N 

Neutral: Current-carrying conductor that completes the circuit back to the source, colour blue. 

O 

Ohm, Ω: Unit of electrical resistance. 
Overcurrent: Current exceeding the rated value that can cause damage or danger. 

P 

Part P: Building Regulations in England and Wales covering electrical safety in dwellings. 
PAT testing, portable appliance testing: In-service inspection and testing of appliances. 
Phase: In single-phase systems the line conductor, in three-phase systems one of the three line conductors. 

Q 

Quiescent: Idle or standby state with very low power draw. 

R 

RCD, residual current device: Trips when detecting imbalance between line and neutral, protecting against electric shock and some fire risks. 
Rewire: Replacement of part or all of an installation. 
Ring final circuit: Socket circuit wired in a ring, typically using 2.5 mm² twin and earth. 

S 

SELV, separated extra-low voltage: System separated from earth to reduce shock risk. 
Socket outlet: Accessory providing connection to the supply. 
Spur: Additional connection from an existing circuit point. 
Supplementary bonding: Local bonding in special locations to reduce touch voltage, for example bathrooms. 
Switchgear: Assemblies of switches, fuses, and breakers that control and protect circuits. 
Surge protective device, SPD: Limits transient overvoltages to protect equipment. 

T 

Transformer: Device that changes AC voltage up or down via magnetic induction. 
Trunking: Enclosed channel for protecting and routing cables. 

U 

UPS, uninterruptible power supply: Battery-backed device that provides power during an outage. 

V 

Volt, V: Unit of electrical potential. 
Voltage categories: Extra-low typically up to 50 V AC, low above 50 V up to 1,000 V AC, high above 1,000 V AC. 

W 

Watt, W: Unit of power, equals volts times amps for resistive loads. 
Wiring diagram: Schematic showing how a circuit’s parts connect. 

X 

Xenon: Gas used in some discharge lamps. 

Y 

Yellow-green: Bi-colour used for protective conductors, the earth identification in fixed wiring. 

Z 

Zone: Defined areas with special electrical rules, for example bathroom zones around a bath or shower. 

Where this glossary fits in your training 

These definitions helps new starters translate site talk into clear actions and safe habits. If you are planning your route, begin with the level 2 electrician course inside the c&g 2365 framework at Elec Training, then build toward inspection skills and real-world compliance. While you learn, keep an eye on career m ilestones and pay structures through our average electrician salary explainer and current JIB rates so you can plan the steps that move your earnings up with your competence. 

Stay safe, label clearly, test methodically, and keep this A to Z close when a bit of jargon tries to trip you up.