Three-phase meters and connections
Short answer. A three-phase meter measures all three phases and accumulates one combined kWh total, so reading it is no harder than a single-phase meter. What is different is that the load should be spread evenly across the three phases — imbalance wastes energy in the neutral, overheats one phase, and shortens the life of everything on it.
Who this is for: Larger homes, shops and small industry on three-phase supply, and anyone considering an upgrade from single phase.
When three phases are actually needed
Three-phase supply is required for motors above roughly five horsepower, for large air conditioning plant, and generally where sanctioned load exceeds what a single-phase service can carry safely.
It is not a way to get cheaper electricity. Domestic three-phase connections are billed on a different schedule and do not pick up the single-phase protected slabs, which surprises households that upgraded expecting a saving.
Balancing the phases
In a well-arranged installation, each phase carries roughly a third of the load. In most real ones, the phase that happened to be wired to the kitchen and the air conditioners carries far more than the others.
The consequences are real: additional losses in the neutral conductor, voltage drop on the overloaded phase, and equipment on that phase running at reduced voltage and drawing more current for the same work.
Rebalancing is a rewiring job at the distribution board, and on an unbalanced installation it is one of the few electrical changes that measurably reduces consumption rather than merely improving safety.
Single-phasing and why a preventer matters
If one phase fails at the pole — a common occurrence — a three-phase motor keeps running on two and draws heavily to compensate. Within minutes the windings can be destroyed.
A single-phase preventer disconnects the load when any phase drops. On any connection with a three-phase motor, it is not an accessory; it is the difference between an outage and a burnt motor.
Reading it
The kWh screen accumulates the combined energy of all three phases; there is no need to add anything up. Most three-phase meters also show per-phase voltage and current, which is exactly the diagnostic you need to check balance.
Note all three current readings under normal load. If one is materially higher than the others, that is the rebalancing case, in numbers.
Frequently asked questions
Is three-phase electricity cheaper per unit?
No. It is billed under a different schedule, and for domestic consumers that schedule generally does not include the protected slabs available on single-phase supply. Upgrade for capacity, not for price.
Can I run single-phase appliances on a three-phase connection?
Yes — each phase to neutral gives a normal single-phase supply, which is how a three-phase house feeds its lights and sockets. Spreading them evenly across the three phases is the part that matters.
Related meter guides
Go further
All 10 guides are listed in the meter guides index. To check the reading against your actual bill, open the official duplicate.