100 One Liners Q&A on Building Electrifications

Q: What is building electrification?
A: It is the process of providing electrical wiring and equipment to buildings.
Q: What is the standard frequency of AC supply in India?
A: 50 Hz
Q: What is the standard voltage for residential buildings in India?
A: 230V single-phase
Q: What is the voltage for three-phase supply in India?
A: 415V
Q: Which wire carries current in normal operation?
A: Phase wire
Q: Which wire is used for safety in wiring systems?
A: Earth wire
Q: What is earthing?
A: Connecting the non-current carrying parts to the ground.
Q: Why is earthing important?
A: To prevent electric shocks.
Q: What is a circuit breaker?
A: A device that interrupts fault current automatically.
Q: What does MCB stand for?
A: Miniature Circuit Breaker

Q: Name one common type of wiring system.
A: Conduit wiring
Q: What is surface conduit wiring?
A: Conduits fixed on the wall surface.
Q: What is concealed conduit wiring?
A: Conduits hidden inside walls.
Q: Which wiring is best for aesthetic purpose?
A: Concealed wiring
Q: What is CTS wiring?
A: Cable Trunking System wiring
Q: What is the disadvantage of wooden casing wiring?
A: Fire hazard
Q: What is the main purpose of distribution board?
A: To distribute power to various circuits.
Q: What is a busbar?
A: A conductor that distributes power to multiple circuits.
Q: What type of cable is used for internal wiring?
A: PVC insulated cable
Q: What is the color code for neutral wire in India?
A: Black or Blue

Q: What is connected load?
A: Total load of all appliances connected.
Q: What is demand factor?
A: Ratio of maximum demand to connected load.
Q: What is diversity factor?
A: Sum of individual max demands / max demand on system.
Q: What is power factor?
A: Ratio of real power to apparent power.
Q: Why is power factor correction important?
A: To reduce electricity bill and losses.
Q: What is maximum demand?
A: Highest power demand in a period.
Q: What unit is used for measuring energy consumption?
A: kWh (kilowatt-hour)
Q: Name an energy-efficient lighting system.
A: LED lighting
Q: What is the average load?
A: Load over a time period divided by time.
Q: Name an electrical load that causes inductive effect.
A: Motor

Q: What is fuse?
A: A protective device that melts during overload.
Q: What is ELCB?
A: Earth Leakage Circuit Breaker
Q: What is RCCB?
A: Residual Current Circuit Breaker
Q: What rating is typically used for residential MCBs?
A: 6A to 32A
Q: What is short circuit?
A: A low resistance connection causing high current.
Q: What is overload?
A: When current exceeds safe limit for a circuit.
Q: Name a fireproof wire insulator.
A: Mica
Q: What is the main cause of electric shock?
A: Current flowing through the body.
Q: What is insulation resistance?
A: Resistance between conductor and earth.
Q: What should be done in case of electric fire?
A: Use CO₂ or dry powder extinguisher.

Q: What is a switch?
A: Device to make or break a circuit.
Q: What is a socket?
A: Device to plug in appliances.
Q: What is a ceiling rose?
A: A connector for ceiling-mounted fixtures.
Q: What is the function of fan regulator?
A: To control fan speed.
Q: What is the standard pin configuration of a plug?
A: 3-pin (live, neutral, earth)
Q: What is the current rating of standard household socket?
A: 6A or 16A
Q: What does ISI mark on appliances mean?
A: Certified by Indian Standards
Q: What is a relay used for?
A: Automatic switching
Q: What is the function of contactor?
A: High current switching
Q: What is thermostat?
A: Temperature control device

Q: What is electrical estimation?
A: Predicting materials and cost before installation.
Q: What is schedule of rates?
A: List of rates for electrical works.
Q: What is labour cost?
A: Cost of workforce for installation.
Q: What is contingency in costing?
A: Extra allowance for unexpected expenses.
Q: What is depreciation in electrical installation?
A: Reduction in value over time.
Q: What is quantity surveying?
A: Estimating quantities of materials.
Q: What is material cost?
A: Cost of all electrical items used.
Q: What is a tender?
A: An offer to execute work at a certain price.
Q: What is BOQ?
A: Bill of Quantities
Q: What is the main aim of estimation?
A: To avoid cost overrun.

Q: What is a distribution box?
A: Contains MCBs to distribute power.
Q: What is the use of main switch?
A: To isolate power supply to the entire system.
Q: What is phase balancing?
A: Equal load distribution in 3-phase system.
Q: What is MDB?
A: Main Distribution Board
Q: What is SDB?
A: Sub Distribution Board
Q: What is load center?
A: A central point for circuit protection.
Q: What is TPN switch?
A: Triple Pole with Neutral switch
Q: What is SPN switch?
A: Single Pole with Neutral switch
Q: What is switchgear?
A: Combination of switching and protective devices.
Q: What is the function of isolator?
A: Manual disconnection from supply.

Q: What is a megger?
A: Device to measure insulation resistance.
Q: What is lux level for a classroom?
A: 300–500 lux
Q: What is load shedding?
A: Scheduled power cuts to reduce load.
Q: What is earthing resistance limit for domestic wiring?
A: Less than 1 ohm
Q: What is neutral wire used for?
A: Return path for current.
Q: What is automatic changeover switch?
A: Switches supply between mains and generator.
Q: What is emergency lighting?
A: Lighting during power failure.
Q: What is inverter?
A: Converts DC to AC
Q: What is UPS?
A: Uninterrupted Power Supply
Q: What is load curve?
A: Graph of load vs. time.

Q: What is IE rule?
A: Indian Electricity Rules
Q: What is standard height for switchboard?
A: 1.2–1.5 meters from floor
Q: Which code governs building electrification in India?
A: IS 732
Q: What is IEC?
A: International Electrotechnical Commission
Q: What is BIS?
A: Bureau of Indian Standards
Q: What is NEC?
A: National Electrical Code
Q: What is license wiring?
A: Wiring done by certified electrician.
Q: What is third-party inspection?
A: Independent check of installation.
Q: What is the minimum size of earth wire in domestic wiring?
A: 1.5 sq. mm
Q: What is a loop-in system?
A: Wiring method where each fitting gets live wire directly.