Domestic Electrical Installer – Essential Electrics Vocabulary

Vocabulary flashcards covering circuit types, cable sizes, regulations, and installation terminology from Domestic Electrical Installer Section 1 Part A notes.

32 A Ring Final Circuit

A looped circuit protected at 32 A that supplies 13 A socket outlets in domestic premises.

6 A Lighting Circuit

Low-current circuit, typically protected at 6 A, dedicated solely to lighting points.

Ring Final Circuit

Circuit whose cable leaves the consumer unit and returns, forming a complete loop while feeding socket outlets.

Radial Circuit

Circuit that starts at the consumer unit and terminates at the last outlet without returning, forming no loop.

20 A Radial Circuit

Single-run socket circuit protected at 20 A; may serve up to 50 m² floor area and ends at the last outlet.

Spur Outlet

Additional socket taken from an existing circuit that does not form part of the original ring or radial route.

Non-Fused Spur

Spur supplying one socket outlet and relying on the ring’s protective device rather than its own fuse.

PVC/PVC Cable

Twin-and-earth cable with PVC insulation and PVC sheath commonly used in domestic wiring.

6.0 mm² Cable

Conductor size traditionally used for cooker and shower circuits, though may be undersized for modern higher-kW units.

2.5 mm² Cable

Conductor size once standard for 20 A radial socket circuits and immersion heaters.

Current-Carrying Capacity

Maximum continuous current a cable can handle without exceeding its temperature rating.

BS 7671

The UK Wiring Regulations setting safety and design requirements for electrical installations.

Appendix 15 (BS 7671)

Guidance section covering design and arrangement of ring and radial final circuits.

Regulation 433.1

BS 7671 provision dealing with protection against overcurrent in final circuits.

Appendix 4 (BS 7671)

Contains cable current-carrying capacity tables and correction factors.

Consumer Unit

Distribution board housing circuit-breakers, RCDs, and other protective devices for a premises.

RCD (30 mA)

Residual Current Device that disconnects the circuit when leakage exceeds 30 mA, giving additional shock protection.

Pattress (Surface Box)

Plastic box fixed on a wall surface to mount a socket or switch outlet.

Mini-Trunking

Small plastic cable containment used for neat surface-mounted wiring routes.

Immersion Heater Circuit

Dedicated supply for a water-heating element; sizing now determined by BS 7671 rather than default 2.5 mm².

Cooker Circuit

Circuit feeding an electric cooker, traditionally 6.0 mm² but now sized to appliance demand and installation method.

Shower Circuit

High-load circuit supplying an electric shower, requiring cable sized to modern higher kW ratings.

Floor Area Limitation (Radial)

Rule limiting a 20 A radial socket circuit to rooms totalling no more than 50 m².