Single-phase or three-phase: how we decide
The question is settled by looking at two things, and neither of them is the charge point: the supply that arrives at your house, and what the car will accept.
Updated on 14 September 2026
What your supply already allows
Three kinds of supply sit behind Belgian houses. Single-phase 230 V, one line and a neutral, is the most common. Three-phase 400 V with neutral, four wires, is the modern connection. And between them the inherited 3 × 230 V with no neutral, still found in many pre-1980 houses across Hesbaye and the Condroz.
The third is the trap, because it has three phases and gets mistaken for ordinary three-phase. The voltage between phases there is 230 V and not 400, so the power available at the same breaker rating is about a third lower.
It reads off the meter and the board in two minutes, and it is the first thing we look at before anyone talks about charge point ratings.
What the same charge point delivers, by supply
| Supply | Rating | Power available | The arithmetic |
|---|---|---|---|
| Single-phase 230 V | 32 A | 7.4 kW | 230 V × 32 A |
| 3 × 230 V, no neutral | 16 A | 6.4 kW | 1.73 × 230 V × 16 A |
| 3 × 230 V, no neutral | 32 A | 12.7 kW | 1.73 × 230 V × 32 A |
| Three-phase 400 V | 16 A | 11.1 kW | 1.73 × 400 V × 16 A |
| Three-phase 400 V | 32 A | 22.2 kW | 1.73 × 400 V × 32 A |
The middle row is the one that surprises people: a unit sold as an 11 kW charge point delivers 6.4 kW on a 3 × 230 V supply. The unit is not at fault and neither is the network. The quotation should have said so.
The car often caps out before the charge point does
A charge point does not set the power on its own. The car onboard charger imposes a ceiling on alternating current, and many models stop at 11 kW, some at 7.4. A 22 kW unit connected to a car that accepts 11 charges at 11, and the extra you paid never does anything.
The figure is on the vehicle data sheet, under AC charging or home charging, and has nothing to do with the DC rapid charging power the brochures put on the cover.
So we ask for the model before proposing a rating. Where the car caps at 7.4 kW, a single-phase unit is the right answer and three-phase is money hung on a wall.
What genuinely tips the decision to three-phase
- Two cars on the same point, or a second one on the way.
- A heat pump, an induction hob and a cylinder already in place: the house reaches its ceiling before the charge point does.
- A car whose onboard charger really does accept 11 kW or more.
- A supply that has to be reworked anyway, in which case the extra cost of three-phase is marginal against the job.
- Conversely, one car sitting at home for twelve hours needs nothing beyond single-phase. The night is longer than the charge.
Tell us what is in your consumer unit
Describe what sits on your board and we will say what can be shifted and what cannot. By phone on +32 495 88 75 92 or through the questionnaire.
Sources for this page
- ORES, the 2026 distribution tariffsChecked on 2026-09-14