SWA
Steel Wire Armoured
A cable with steel wires around its cores to give mechanical protection, often selected for outdoor or underground routes. The armour may serve as a protective conductor only when the whole design, glands and connections make a suitable continuous path. SWA names the cable construction, not permission to bury it without a route assessment.
Using SWA in context
Updated
A distinction worth remembering
Steel wire armour provides mechanical protection and may have a protective-conductor role where properly designed and connected. Do not assume every armoured cable installation uses the armour in the same way.
Questions to take further
- How can I revise SWA beyond the definition?
- Explain what SWA describes, compare it with a related term and use it in a topic question. State any assumptions and what evidence you would need before applying the idea to real work.
Sources
- IET: current BS 7671 edition and updates — BS 7671:2018+A4:2026 and the main subject areas updated by Amendment 4.
- IET: earthing and bonding FAQs — Protective bonding, earthing arrangements and loop impedance.
Where SWA fits in the learning path
The Installation section covers these units:
- Wiring Systems & Enclosures
- Cable Selection & Circuit Design
- Earthing, Bonding & Consumer Units
Curriculum mapping: C&G 2365 Units 203/204/305.
See this section in the full curriculum
This section is on the Plus path. Lesson availability depends on content review and your learning path.
Read, practise, return
1. Read it in context
- Cable SizingInstallation
- Earthing & BondingInstallation
2. Try recalling, then explore practice
Use the memory prompt below to connect the vocabulary.
- Cable Selection — quiz previewPlus · Installation
3. Return to the meaning
After reading or practising, explain the idea in your own words, then check what you remembered.
Recall a related term
Which term fits this definition? Say it to yourself, then reveal it. This is a memory prompt, with no score or saved result.
The earth wire of a circuit. It links the metal parts of the equipment the circuit feeds back to the main earthing terminal. It is not the normal load-current return path, although equipment can produce protective-conductor current in normal operation. During an earth fault it provides a path for fault current, working with the earthing arrangement and protective device to achieve disconnection. In UK wiring it is green and yellow, or bare inside twin-and-earth cable, with green-and-yellow sleeving wherever it is exposed.
Compare related terms
Open a meaning to compare its role with SWA, or follow its full entry.
CPC — Circuit Protective Conductor
The earth wire of a circuit. It links the metal parts of the equipment the circuit feeds back to the main earthing terminal. It is not the normal load-current return path, although equipment can produce protective-conductor current in normal operation. During an earth fault it provides a path for fault current, working with the earthing arrangement and protective device to achieve disconnection. In UK wiring it is green and yellow, or bare inside twin-and-earth cable, with green-and-yellow sleeving wherever it is exposed.
Read the CPC entryEarthing
Connecting an installation's exposed metalwork to earth, so that fault current has a deliberate path back to the supply. If the line conductor touches an earthed casing, that current lets a protective device switch the supply off automatically: a fuse or circuit breaker where the current is large, an RCD where it is small, as in a home with its own earth rod. Without earthing, a faulty casing can simply stay live.
Read the Earthing entryContainment
The system that carries or encloses wiring along its route, such as conduit, trunking, tray or basket. It helps support and protect cables and keeps runs organised for installation and maintenance. The material and fixing method must suit the location and the cables; containment alone does not prove a circuit safe.
Read the Containment entryA definition is a start. Using it in a real question is where it sticks.