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Classification of electrical consumers and demand

Short answer

Consumers are classified as domestic, commercial, industrial, agricultural, street lighting, and public utilities. Domestic loads are small, peak in evening, with low load factor; industrial loads are large, steady, with high load factor. Agricultural demand is seasonal, and different peak times give a diversity factor above one.

Explain the classification of electrical consumers and their demand.

Electrical consumers are classified according to the purpose of use, size of load and supply voltage. Each class has a typical demand pattern, load factor and peak time, which the utility uses for planning and tariff setting.

Classes of consumers

1. Domestic (residential)

  • Loads: lights, fans, TV, refrigerator, water heater, cooker, iron, pumps.
  • Demand: small (about 0.5 to 10 kW); 230 V single-phase or 400 V three-phase.
  • Peak in the evening; low load factor (about 10 to 20 %); high diversity among households.

2. Commercial

  • Shops, offices, hotels, restaurants, hospitals, cinemas, banks.
  • Loads: lighting, air-conditioning, lifts, computers.
  • Demand: medium; peak during business hours; load factor about 25 to 40 %; 400 V or 11 kV.

3. Industrial

  • Small-scale (up to about 50 kW, 400 V), medium-scale (about 50 to 1000 kW, 11 kV), large-scale (above about 1 MW, 33 kV and above).
  • Loads: motors, furnaces, welding, electrolysis, lighting.
  • Demand: large and steady; high load factor (60 to 80 % for multi-shift plants); needs reactive power, so power-factor correction.

4. Agricultural (irrigation)

  • Pumps, threshers, mills. Seasonal, mostly daytime; low load factor (about 15 to 25 %).

5. Street lighting

  • Fixed night-time load (dusk to dawn); load factor about 40 to 50 %; predictable.

6. Public utilities and others

  • Water supply and sewage pumping (fairly continuous), traction and EV charging (fluctuating), temples, community, government institutions, bulk supply.

Comparison of demand

ClassSizeVoltageLoad factorPeak
DomesticSmall230/400 V10-20 %Evening
CommercialMedium400 V/11 kV25-40 %Day
IndustrialLarge400 V-132 kV60-80 %Day/continuous
AgriculturalMedium400 V/11 kV15-25 %Dry season
Street lightSmall230/400 V40-50 %Night
 kW
  |                          domestic
  |      commercial _____     /\
  |   industrial ___/~~~~\___/  \__
  |__/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  +-------------------------------- hour
  0     6     12     18     24

Because the classes peak at different times, the diversity factor of the system is greater than 1, so the generating capacity required is less than the sum of the individual maximum demands. The values above are typical textbook ranges and vary from system to system.

✓ Answer checked by Claude Opus 5.5 (high effort)

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