Plan the wiring for your home. Enter how many of each appliance you have and the calculator adds up the load, estimates the demand, and suggests a main breaker, a main cable size and the typical circuits to run.
| Appliance | Qty | Watts each |
|---|---|---|
| LED bulb | ||
| Tube light or LED panel | ||
| Ceiling fan | ||
| Air conditioner 1.5 ton | ||
| Refrigerator | ||
| Deep freezer | ||
| Washing machine | ||
| Iron | ||
| Water pump 1 HP | ||
| Electric geyser | ||
| Microwave oven | ||
| TV | ||
| Computer or laptop | ||
| Other load (watts) |
Typical values for a single phase home. The wattages are common defaults, so replace them with the numbers on your appliance labels. This is a planning guide, not a substitute for a licensed electrician or local wiring rules.
Formulas and assumptions
- Connected load: sum of quantity times watts for every appliance
- Demand: connected load times the demand factor. Not everything runs at once, and 60 to 80 percent is common for homes
- Demand current: demand watts divided by (volts times 0.9 power factor)
- Main breaker: next standard size at or above the demand current
- Circuits: typical practice is 1.5 mm2 for lights, 2.5 mm2 for sockets and 4 mm2 for air conditioners and geysers, but local rules decide
Example
With the default home (8 LED bulbs, 4 tube lights, 5 fans, one 1.5 ton AC, a fridge, washing machine, iron, pump, TV and computer) the connected load is 4.99 kW. At 70 percent demand that is 3.49 kW, or 16.9 A at 230 V, so a 20 A main breaker and a 4 mm2 main cable fit, with a separate circuit for the AC.
Frequently asked questions
What size wire should I use for home wiring?
Typical single phase practice is 1.5 mm2 copper for lighting, 2.5 mm2 for sockets and fans, and 4 mm2 or larger for air conditioners and water heaters. Follow your local wiring code.
What is a demand factor?
It is the share of your connected load that runs at the same moment. A home never uses every appliance together, so the demand is lower than the sum of all the watts.
Do I need a three phase connection at home?
Many homes are fine on single phase up to roughly 8 to 10 kW of demand. Large homes with several air conditioners often need three phase. Ask your utility.
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