I get a lot of questions about 3 phase metering and how the meter calculates the electricity bill.

Single phase is simple - KWh = Watts X hours/1000

For example: If you leave a 3000 watt geyser running for 2 hours it means that you have consumed 3000 w X 2 hours/ 1000 = 6 kwh

If your tariff is R2.10 per kwh, it means your bill will be R12.60

Now we go to a 3 phase 400 VAC meter, this gets a little more complicated.

The most common question I get asked : If the load is unbalanced will the bill be calculated on the highest phase, or do the meters read and average across the phases.

This is good question, because you need to understand how your meter works. If you have a smart meter it will add up each phase and display a total, but if you have an old dial type meter, there is a centre spindle with 3 coils attached.

How important is it to balance the phases on a 3 phase DB (especially residential) ?

Do you pay a higher tariff if you have 3 phase power?

Do you pay a service fee for 3 phase power ?