Home Battery and AREI: Correctly Integrating Battery Storage into Your Electrical Installation

Home battery systems are becoming increasingly popular in Belgium. If you have a PV installation, a home battery lets you maximise self-consumption and reduce your reliance on grid electricity. But what does a correct installation look like according to AREI regulations? This guide walks you through all the requirements.

Why a Home Battery?

With the digital meter in Belgium, self-consumption is more worthwhile than ever. A home battery stores excess solar power during the day and releases it in the evening. Typical savings range from 30-60% of grid consumption, depending on battery capacity and consumption profile.

The AREI has no dedicated chapter for domestic home battery storage — the general rules apply (protection against electric shock, overcurrent protection, isolation/safety disconnection). The dedicated battery chapter 7.103 (industrial accumulator batteries) explicitly excludes domestic installations. Where the battery is coupled with a PV installation, Art. 7.112 (domestic low-voltage photovoltaic installations ≤ 10 kVA) applies to the PV part; the battery itself does not fall under it.

AREI Requirements for Home Batteries

Dedicated Circuit

The home battery (specifically the inverter/hybrid inverter) requires its own dedicated circuit in the distribution board. This circuit must not be shared with other consumers.

• Protection: Dedicated MCB (circuit breaker), typically 20A or 32A depending on inverter power. Cable cross-sections: 20 A breaker → min. 2.5 mm², 32 A breaker → min. 6 mm²
• RCD Protection: 30 mA RCD upstream. For single-phase inverters, Type A is sufficient. For three-phase inverters without integrated DC residual current monitoring (RCMU), Type B is required. Many modern inverters (Huawei, Fronius) have an integrated RCMU that allows Type A

Disconnect Switch (Isolation Point)

Between the battery/inverter and the grid, an all-pole disconnect switch must be installed. This allows the battery system to be completely isolated from the grid — essential for maintenance work and for the safety of grid technicians.

Surge Protection (SPD)

A surge protection device (SPD) is recommended at the AC connection. Art. 4.5.1 establishes the general principle that persons and property must be protected against overvoltages, but does not mandate a specific SPD type. On the DC side, an SPD is also advisable, especially for outdoor cabling.

Ventilation for Lithium Batteries

Lithium-ion batteries (as used in all common home battery systems) require adequate ventilation of the installation room. The room must not develop excessive heat (recommended: max. 35°C). For larger systems, active ventilation may be necessary.

Integration in the Single-Line Diagram

The single-line diagram must correctly represent the home battery. The integration covers two sides:

DC Side

The direct current side shows the path from the battery pack through the battery management system (BMS) to the inverter:

• Battery → BMS → DC disconnect switch → Hybrid inverter
• For AC-coupled systems: Battery → dedicated battery inverter → AC connection

AC Side

The alternating current side shows the integration into the household network:

• Hybrid inverter → AC disconnect switch → MCB → Distribution board
• The connection is typically made after the main switch but before the individual circuit RCDs

Representation in the Diagram

In the single-line diagram, the home battery appears as its own branch, similar to the PV installation. The symbols include:

• Battery symbol (per IEC 60617)
• Inverter symbol
• Disconnect switch
• Associated MCB and RCD

Backup / Emergency Power Function

Many modern home batteries offer a backup function. When the grid fails, the battery continues to supply selected circuits.

Transfer Switch

If a backup function is desired, a transfer switch must be installed:

• Automatic Transfer Switch (ATS): The inverter automatically switches to island mode. Most hybrid inverters have this built in.
• Manual Transfer Switch: A changeover switch allows manual disconnection from the grid and operation in island mode.

The transfer switch must be shown in the single-line diagram and must be all-pole isolating, so that no power is fed back into the failed grid (danger for grid technicians).

Registration with the Grid Operator

The installation of a home battery must be reported to the grid operator (Fluvius in Flanders, ORES/RESA in Wallonia):

• With existing PV installation: Modification notification — the installation is registered as PV + battery
• Technical data: Capacity (kWh), inverter power (kW), AC or DC coupling
• New single-line diagram: An updated diagram must be submitted
• Electrical inspection update: For substantial changes, a new inspection (keuring) may be required

Popular Systems in Belgium

Costs and Return on Investment

• Investment: EUR 4,000-8,000 for a 5-10 kWh system (including installation)
• Savings: EUR 300-600 per year, depending on self-consumption ratio
• ROI: 8-15 years — most worthwhile with high daytime consumption and a large PV installation
• Subsidies: Check regional premiums (vary by region and year)

ROI improves with rising electricity prices and falling battery costs. Realistic sizing is important: an oversized battery extends the payback period.

Home Battery in the Single-Line Diagram with PlanElec

With PlanElec, you can correctly document the home battery in the single-line diagram. The software accounts for:

• Dedicated circuit with MCB and RCD
• Disconnect switch and SPD
• Correct symbols per IEC 60617
• AREI compliance validation

Related articles:

• AREI Regulations 2026: What Has Changed?
• Dedicated Circuits: Which Appliances Need Their Own Circuit?
• Cable Cross-Section and Breaker: The Right Combination

Document your home battery in full AREI compliance with PlanElec — complete in the single-line diagram. Get started →