Guide

Single-phase or three-phase? Belgian networks and building connections

1×230 V, 3×230 V or 3N~400/230 V: understand the street network, neutral conductor and connection phase count in Belgium.

Published on 27 July 2026 Updated on 3 August 2026 6 min

Short answer: there are more than two cases

Two separate questions matter in Belgium:

The low-voltage street network: 230 V without neutral, or 400/230 V with neutral.
Your individual building connection: single-phase or three-phase.

“Single-phase = 1×230 V” is a valid connection description, but not a separate street-network form. A single-phase 230 V connection can be line-to-neutral from a 400/230 V network or line-to-line from a 3×230 V network. ORES explicitly says that a single-phase connection does not necessarily include a neutral conductor.

The four combinations

Street network	Building connection	Conductors at the connection	Technical notation
400/230 V with N	Single-phase	L + N	1×230 V, L–N
400/230 V with N	Three-phase	L1 + L2 + L3 + N	3N~400/230 V
230 V without N	Single-phase	Two line conductors	1×230 V, L–L
230 V without N	Three-phase	Three line conductors	3×230 V without N

The 3×230 V network is not merely theoretical. Fluvius reported 18,101 km of 230 V low-voltage network at the end of 2024, concentrated especially in urban and western areas. Sibelga says about 80% of Brussels is covered by 230 V. That does not mean every home there has three phases: Sibelga describes 9.2 kVA, single-phase 230 V at 40 A, as its standard household connection.

Power with the same current rating

ORES publishes these values at 40 A:

Connection	Apparent power at 40 A
Single-phase 230 V	9.2 kVA
Three-phase 3×230 V	15.9 kVA
Three-phase 3N~400/230 V	27.7 kVA

Your actual contracted capacity still depends on the connection breaker and the grid operator's records.

EV chargers, heat pumps and solar

EV charger: 3.7 or 7.4 kW may be possible on single phase. 11 or 22 kW normally needs a suitable three-phase connection. Not every device works on 3×230 V; Sibelga lists restrictions for 11/22 kW charging.
Heat pump and cooker: Check the nameplate. Equipment designed for 3N~400 V cannot automatically run on 3×230 V without neutral.
Solar: Permitted inverter power and phase distribution depend on the grid operator and the actual connection. A blanket Belgian 5 kWp rule would be misleading.

Before buying a large load, check both single/three-phase and 230 V without N/400/230 V with N.

RCDs on a 3×230 V network

An RCD does not need a neutral conductor as a “reference”. It compares the currents in all active conductors routed through it. On a 3×230 V network, the participating line conductors must therefore be monitored and switched together. The previous blanket claim that RCD protection is reduced merely because no neutral is present was incorrect.

Phase balancing

Sensible load distribution is good design practice on a three-phase connection. The AREI/RGIE does not, however, prescribe a universal exact 30% limit. Such a threshold may be used as a planning warning, but should not be presented as a verbatim statutory rule. A single-phase connection has no three phases to balance.

Identifying your connection

Check the meter, connection breaker and incoming conductors without opening sealed areas. ORES provides examples of single-phase 230 V, 3×230 V and 3×400 V + N. When in doubt, the grid operator or an electrician can confirm the connection. Counting visible wires alone can be misleading because of PE, internal wiring and legacy installations.

Upgrading or changing the connection

There is no single Belgian price or timeline. It depends on the grid operator, requested capacity, available street infrastructure, meter position and work required inside the building. Ask the relevant grid operator for a specific quotation first. Significant changes may also require updated diagrams and a new inspection.

Sources

Document the network and building connection separately in PlanElec →

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