--- title: "Types of electric wiring system compared" subject: "Industrial Power Distribution and Illumination" chapter: 5 key: "semester_6/industrial_power_distribution_and_illumination:wiring-systems-comparison" source: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/wiring-systems-comparison site: BCT Engineering --- # Types of electric wiring system compared Industrial Power Distribution and Illumination · Chapter 5: Electrification of Industrial Building - Asked in: 2068 Jestha (old course), 8 marks - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/industrial_power_distribution_and_illumination/wiring-systems-comparison - Whole chapter: https://www.bctengineer.com/md/semester_6/industrial_power_distribution_and_illumination/chapter-5 ## Question Explain the various types of electric wiring system. Compare them on the basis of cost, life, maintenance and protection against mechanical injury, fire and moisture. ## Short answer Common wiring systems include cleat (temporary, lowest cost, poor protection), casing-capping (moderate), batten (low cost, neat, fair protection), lead-sheathed (high cost, good moisture/mechanical), and conduit (highest cost, best mechanical/fire/moisture protection, long life, easy rewiring). Conduit is preferred for permanent installations, batten for dry houses, cleat only for temporary works. ## Answer An **electric wiring system** is the method of running insulated conductors from the distribution board to the points (lights, fans, sockets) in a building. The common types are: 1. **Cleat wiring:** PVC or VIR cables are held on porcelain/plastic cleats screwed to walls and ceilings. Cheap and quick; used for temporary installations (exhibitions, construction sites). Untidy and unprotected. 2. **Casing and capping (wooden) wiring:** cables run inside a wooden casing with grooves, covered by a wooden capping. Older method; now replaced by PVC casing (PVC channel) wiring, which is cheaper and resists moisture better. 3. **Batten (TRS/CTS) wiring:** tough-rubber-sheathed or PVC-sheathed cables are fixed on a straight teak-wood batten with brass/aluminium link clips. Neat and cheap; used in residences and offices for indoor dry places. 4. **Lead-sheathed (metal-sheathed) wiring:** cables with an outer lead/aluminium sheath fixed on battens with link clips; the sheath is earthed. Good mechanical and moisture protection but costly and the sheath can corrode. 5. **Conduit wiring:** PVC cables are drawn through steel or PVC conduit pipes. - *Surface conduit:* pipes fixed on the wall surface with saddles (factories, workshops). - *Concealed conduit:* pipes buried in walls/slabs during construction (modern buildings). Best appearance and protection; rewiring is easy by pulling wires through the pipe. #### Comparison | Basis | Cleat | Casing–capping | Batten (TRS/PVC) | Lead sheathed | Conduit (steel/PVC) | |---|---|---|---|---|---| | Cost | Lowest | Low–medium | Low | High | Highest | | Life | Short (temporary) | 10–15 years | 15–20 years | 20–25 years | Longest (30+ years) | | Maintenance | Easy but frequent | Termites, damp attack; moderate | Easy | Low | Lowest; easy rewiring | | Mechanical injury | Very poor protection | Fair | Fair | Good | Excellent | | Fire risk | Poor | Poor (wood burns) | Fair | Good | Excellent (steel conduit) | | Moisture | Poor | Poor (wood absorbs) | Fair (sheath resists) | Good | Excellent if sealed | | Appearance | Untidy | Fair | Neat | Neat | Best (concealed) | | Typical use | Temporary works | Old dry buildings | Houses, offices | Damp places | Factories, modern buildings | **Choice:** concealed PVC conduit wiring for modern residential and commercial buildings; surface steel conduit or armoured cable in factories with risk of mechanical damage and fire; cleat wiring only for temporary work. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. For which use is cleat wiring suited, and why? A. Permanent factory wiring, since it is the best protected B. Temporary installations, because it is cheap and quick but unprotected C. Underground cabling D. Hazardous areas Answer: B. Cleat wiring is lowest cost and quick to install, but untidy and poorly protected, so it is for temporary work. (Key point: Cleat wiring) 2. Why is conduit wiring rated best? A. Cheapest and shortest life B. Excellent protection against mechanical injury, fire and moisture, long life and easy rewiring C. No protection but neat D. Wood-based and moisture absorbing Answer: B. Conduit gives the best protection and longest life, and wires can be drawn out and replaced, though it costs most. (Key point: Conduit wiring) 3. What is a weakness of wooden casing and capping? A. Wood burns and absorbs moisture, and is attacked by termites B. It is too expensive C. It gives the best fire protection D. It cannot be used indoors Answer: A. Wooden casing has poor fire and moisture performance and termite risk, so PVC casing replaced it. (Key point: Casing-capping weakness) 4. Which system is suited to damp places due to a good moisture-resistant earthed sheath? A. Cleat wiring B. Lead-sheathed wiring C. Wooden casing-capping D. Batten wiring on teak only Answer: B. Lead-sheathed cables have good mechanical and moisture protection (sheath earthed), though costly. (Key point: Damp places) ## Related in Industrial Power Distribution and Illumination - [Electric vs mechanical drive, individual vs group](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aelectric-vs-mechanical-drive) — Industrial Power Distribution and Illumination, chapter 5 - [Cable selection against fire, halogen-free cable](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Acable-selection-fire-halogen-free) — Industrial Power Distribution and Illumination, chapter 3 - [Energy and cost saving from lighting retrofit](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Alighting-retrofit-100kw) — Industrial Power Distribution and Illumination, chapter 10 - [Electric building heating methods](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Abuilding-electric-heating) — Industrial Power Distribution and Illumination, chapter 5 - [Earthing for shock protection and methods](https://www.bctengineer.com/question.md?key=semester_6%2Findustrial_power_distribution_and_illumination%3Aearthing-protect-human-methods) — Industrial Power Distribution and Illumination, chapter 2 ## Related in other subjects - [Electrification system and fire protection](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aelectrification-fire) — Building Technology, chapter 12 - [Short note: Fire protection in building](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Ashort-fire-protection) — Building Technology, chapter 12, asked 2× - [Protection and maintenance of water supply](https://www.bctengineer.com/question.md?key=semester_5%2Fwater_supply_engineering%3Aws-maintenance-types) — Water Supply Engineering, chapter 7, asked 4× - [Substation protection against direct strokes](https://www.bctengineer.com/question.md?key=semester_6%2Fswitchgear_and_protection%3Asubstation-direct-stroke-protection) — Switchgear and Protection, chapter 5