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Construction & Homeelectrical

Electrical Load Calculator

Household electrical load with a diversity factor. Sizing on connected load rather than diversified load overstates the requirement substantially, because everything is never switched on at once.

Also called: house load calculator, sanctioned load calculator.

W
W
W
W
W
%
V
Diversified load
5,220

5,220 W after a 60% diversity factor on a connected load of 8,700 W. That draws 23.89 A at 230 V, needing a 32 A main. The sanctioned load should be about 5.22 kW. Diversity reflects that appliances are not all on at once. Sizing on connected load oversizes the supply.

Connected load
8,700
Current draw
23.89
Recommended main breaker
32
Sanctioned load
5.22
Apparent power
5.5
On diversity
Diversity reflects that appliances are not all on at once. Sizing on connected load oversizes the supply.
On regulation
This is a sizing estimate. The applicable wiring or building regulation governs and overrides any figure here.
How this is calculated
Method and background

How this is calculated

Connected load is the sum of everything installed. Diversity recognises that a household never runs every appliance simultaneously, and a factor of fifty to seventy percent is typical for domestic supply. The current follows from the diversified load divided by voltage and power factor, and the main breaker is sized above that. Sanctioned load from the utility is usually specified in kilowatts and set from the diversified figure rather than the connected one.

diversity accounts for the fact that everything is never on at once
d
Diversity factor
pf
Power factor

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

a typical household

Lighting
400 W
Fans
300 W
Air conditioning
3,000 W
Kitchen appliances
3,500 W
Everything else
1,500 W
Diversity factor
60%
Supply voltage
230 V
Power factor
0.95

Diversified load5,220

8700 x 0.6; 5220 / (230 x 0.95)

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no diversity means the full connected load

Lighting
400 W
Fans
300 W
Air conditioning
3,000 W
Kitchen appliances
3,500 W
Everything else
1,500 W
Diversity factor
100%
Supply voltage
230 V
Power factor
0.95

Diversified load8,700

boundary: everything on at once

Open this example

Method and limits

What it assumes

  • Single-phase supply at the stated voltage and power factor.

What it deliberately does not model

  • Diversity factors differ by regulation and by the mix of appliances.
  • Motor starting currents can far exceed running current and are not modelled.
  • Three-phase supply changes the current calculation by a factor of root three.

Formula version 1.0.0 · definition 1.0.0 · India · Report a problem with this calculator

Frequently asked questions

Why is the diversified load lower than the total?
Because appliances are not all on at once. Sizing the supply for every device running simultaneously would oversize it substantially and cost more for no benefit.