--- title: "Electrification system and fire protection" subject: "Building Technology" chapter: 12 key: "semester_6/building_technology:electrification-fire" source: https://www.bctengineer.com/q/semester_6/building_technology/electrification-fire site: BCT Engineering --- # Electrification system and fire protection Building Technology · Chapter 12: Other services in building - Asked in: 2078 Baisakh, 2+2 marks - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/building_technology/electrification-fire - Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-12 ## Question Explain briefly electrification system and protection of fire from electricity. ## Short answer Electrification brings supply from utility to meter, main switch, distribution board, and circuits with earthing. To protect against electrical fire, use correctly sized conductors and MCBs, ELCB/RCD for leakage, proper earthing, avoid overloading, and use CO2 or dry powder extinguishers after switching off the mains. ## Answer #### Electrification system **Electrification** of a building means bringing the electric supply from the utility line and distributing it safely to all lights, fans, sockets and appliances. 1. Service connection from the pole/transformer through a service cable to the **energy meter** (with main fuse/cut-out). 2. **Main switch** and main distribution board (MDB), with MCCB/MCB and ELCB. 3. **Sub-circuits:** separate circuits for lighting (5 A, about 10 points per circuit), power (15 A sockets) and heavy loads (AC, geyser, motor). 4. Wiring in (concealed) conduit with switches, sockets and fittings, and **earthing** of the system. ```text Pole -> meter -> main switch -> MDB -> circuits -> loads earth pit ``` #### Protection from fire due to electricity Electrical fires are caused by short circuits, overloads, loose connections and poor insulation. Protective measures: - Correct conductor size and fuse/MCB rating; do not overload. - Quality wires; joints insulated and enclosed in junction boxes; conduits to contain sparks. - MCB/MCCB for overcurrent, ELCB/RCD for earth leakage; proper earthing; lightning arrester. - Keep wires away from flammable materials and heat; maintain clearances. - Regular inspection and insulation testing. - Use CO2 or dry powder extinguishers (not water) for electrical fires, and switch off the mains first. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What does electrification of a building mean? A. Bringing the utility supply and distributing it safely to lights, fans, sockets and appliances B. Only installing earthing C. Producing power with a generator on site D. Installing lifts Answer: A. Electrification is bringing supply from the utility line and distributing it safely to all loads. (Key point: Electrification) 2. What is the correct order of the supply path in a building? A. Loads, circuits, MDB, meter, pole B. MDB, pole, meter, loads C. Pole, meter, main switch, MDB, circuits, loads D. Meter, pole, loads, MDB Answer: C. Supply goes from pole to energy meter, main switch, main distribution board, circuits and then loads. (Key point: Supply sequence) 3. Which are the main causes of electrical fires? A. Earthing and fuses B. Short circuit, overload, loose connections and poor insulation C. Use of conduit D. Regular insulation testing Answer: B. Short circuit, overload, loose connections and poor insulation produce heat and sparks that start fires. (Key point: Causes of electrical fire) 4. Which device protects against earth leakage? A. ELCB/RCD B. A plain switch C. A lightning arrester only D. An energy meter Answer: A. ELCB/RCD detects earth leakage and cuts the supply; MCB/MCCB handle overcurrent. (Key point: Protective devices) 5. What should be done when an electrical fire occurs? A. Throw water on it at once B. Switch off the mains first and use CO2 or dry powder, never water C. Use a wet chemical extinguisher on live wires D. Leave the mains on to keep alarms working Answer: B. Switch off the mains, then use CO2 or dry powder; water conducts electricity and risks shock. (Key point: Fighting electrical fire) ## Related in Building Technology - [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× ## Related in other subjects - [Fire fighting system in power station](https://www.bctengineer.com/question.md?key=semester_7%2Fpower_plant_equipment%3Afire-fighting-power-station) — Power Plant Equipment, chapter 4, asked 5× - [Protection requirements; protective system vs scheme](https://www.bctengineer.com/question.md?key=semester_6%2Fswitchgear_and_protection%3Aprotective-system-vs-scheme) — Switchgear and Protection, chapter 1 - [T/F: protection ratio vs system voltage](https://www.bctengineer.com/question.md?key=semester_8%2Ftransmission_and_distribution_system_design%3Atf-protection-ratio-system-voltage) — Transmission and Distribution System Design, chapter 3 - [Merits and demerits of DC track electrification](https://www.bctengineer.com/question.md?key=semester_7%2Futilization_of_electrical_energy%3Adc-track-electrification-merits) — Utilization of Electrical Energy, chapter 4