Yes. An off-grid system is an electrical installation like any other, so the AREI inspection before use applies in full. The grid rules of Fluvius only apply when you are connected. In Flanders, an island installation with an inverter of 800 VA or more is notified to the VNR. The inspection and the notification are two separate duties.
You may have read that off-grid needs no inspection. One forum says so, another says everything must be inspected. Fluvius tells you it does not need to know, so nobody will ever ask for a report. And the fire insurer asks for exactly that report.
The risk is not a fine, it is the day something goes wrong. Without a report, you cannot show that the installation was safe when it started. An inspection that finds faults also means the installation may not be used until they are fixed.
Our projects go through this every time. A fully off-grid site in As runs on solar panels, a battery and a propane generator (24 kVA, 30.8 kWh). A private school in Incourt runs completely off-grid on new solar panels, a battery system and a generator. Both are electrical installations under the same code as a house on the grid.
Does an off-grid installation need an AREI inspection?
Yes. Every low-voltage installation is inspected before use, even when a fixed, movable or mobile generator feeds it. That is the wording of the AREI, section 6.4.1. No grid connection is needed for the rule to apply.
The AREI also says where your installation starts. With the grid, it starts at the connection point. Without the grid, the source itself is part of the installation. So the inverter, the battery and the generator are all inside the scope of the inspection.
There is one narrow exception. Installations on extra-low DC voltage, fed only by batteries or solar cells, need no inspection before use. For a business, that only covers small batteries outside the AREI chapter on industrial batteries. A 12 V light in a garden shed can fall under it. A 230 V off-grid system cannot.
| Situation | Inspection before use? |
|---|---|
| Off-grid home, farm or business with an inverter at 230 V or 400 V | Yes |
| Site that runs on a generator | Yes, the AREI names generators explicitly |
| Extra-low DC voltage, only batteries or solar cells, no inverter | No, unless the batteries fall under the industrial battery chapter |
| Adding a circuit, a battery or a generator later | Yes, for the added part |
Why do you hear that off-grid needs no inspection?
Because two sets of rules get mixed up. The grid rules of Fluvius and Synergrid (the federation of grid operators) only apply to installations connected to the grid. The AREI is a federal safety code and applies to every installation.
So when a grid operator says an island installation is none of its business, that is true for the grid rules. It says nothing about the AREI. People asking the question online get answers from both worlds, and even professionals disagree.
Watch out
Did someone tell you that your off-grid installation needs no inspection? Ask where it is written. The AREI text itself is public: chapter 6.4 of Book 1 covers the inspection before use.
Must you report an off-grid installation to Fluvius or the VNR?
In Flanders, an island installation with an inverter of 800 VA or more is notified to the Vlaamse Nutsregulator. The VNR is the Flemish energy regulator. It has its own notification form for installations in island mode.
Island mode has a precise meaning. The VNR defines it as a production installation that normally works without a link to any public grid: distribution, local transmission or transmission. Mobile installations are left out.
The same VNR page sends a direct line on your own site to Fluvius, within 30 days after it is put into use. That route is for production installations on a site that is connected to the grid.
Who needs to know about your installation?
Keep your connection and add a battery, as with a semi off-grid system? Then you are a grid user. Since 1 January 2017 every grid user in Flanders must report a storage system to Fluvius. Below 25 kVA you do that in Mijn Fluvius; larger systems go through a grid study.
The VNR notification is a Flemish rule. In Wallonia, our article on building an energy-autonomous house in Wallonia explains what ORES needs to know when a site stays connected. The AREI inspection applies in all three regions.
What does the inspector check on an off-grid installation?
The inspector checks the whole installation with the power off: papers, a visual check, tests and measurements. A recognised inspection body (erkend organisme) does it on site.
On an off-grid installation, four points get extra attention:
Protection that works on your own source
The AREI requires protection against electric shock that works when one source alone feeds the installation. An inverter or a small generator delivers far less current in a short circuit than the grid. The protection must be chosen for that.
The earth electrode
The inspector measures its resistance. Without the grid, your own earth electrode carries all the protection.
The insulation of every circuit
The insulation resistance is measured per circuit. At a test voltage of 500 V, it must be at least 500 kilohm.
The drawings against reality
The report confirms that the installation matches the single-line diagrams and position plans. In a home, the inspector seals the main residual-current device and signs the drawings.
Businesses have one more chapter to meet. The AREI rules for industrial batteries apply to batteries from 300 Wh, or above 120 V, and to chargers from 200 VA. Battery groups of more than 20 kWh stand in a battery cabinet or a room reserved for the electrical service.
That chapter adds signs at the door: the nominal voltage, no entry for unauthorised people and the electrical hazard. Battery cabinets need ventilation openings and must be made of non-combustible material. Fire safety, permits and insurance for the battery are covered in our article on business battery safety.
How is earthing arranged when there is no grid?
Off-grid, your own earth electrode and your own neutral point do the work that the grid otherwise shares. That is why the inspector looks at the earthing first.
Is the foundation trench of a new home at least 60 cm deep? Then the AREI requires an earth loop at the bottom of that trench, under the outer walls. The earth resistance of a household installation must stay below 100 ohm. For businesses, the AREI asks for an earth connection made according to good practice.
In island mode, the inverter creates the neutral. A Victron MultiPlus-II, for example, has a ground relay that connects the neutral to the chassis when there is no external AC supply. That keeps the residual-current device working when the inverter alone feeds the house.
Tip
Building new without a connection, as in Lokeren? Plan the earth loop before the foundations are poured. It cannot be added under the walls afterwards.
Is the generator in an off-grid installation inspected too?
Yes. A fixed generator is part of the installation it feeds, and the AREI names generators in the rule on inspection before use. In most off-grid designs, it starts only when the battery runs low.
In Zele, a rental company for lifting equipment runs without any grid connection. The generator is planned for about 5% of the yearly demand, mainly in winter. In As, a propane generator plays that role.
A mobile or temporary installation follows stricter rules. It is inspected before every use, and then every year. If the generator has no earth connection of its own, the earth made on site is part of the check.
The switch between generator and inverter matters too. Switching devices act on all live conductors and must not connect sources in parallel by accident. Does the generator also need an environmental permit? Our article on permits and inspection for a back-up generator covers VLAREM, Wallonia and Brussels. For the design itself, read how a generator and a battery share the work.
Which documents do you need for the inspection?
The inspector works from the file of your electrical installation, so have it ready before the visit. The AREI lists what goes into it, and the list is longer for a business.
| Document | Home | Business, farm, school |
|---|---|---|
| Single-line diagrams and position plans | Yes | Yes |
| Inspection report before use and later visit reports | Yes | Yes, the last two visits |
| Equipment documents, manuals, technical references | Yes | Yes, with conformity declarations of the switchgear |
| Calculation notes and risk analyses | No | Where they exist |
| Log of changes since the last visit | Short description of minor changes | Yes |
| Written safety and rescue instructions | Safety rules for use | Yes, available to staff |
A home keeps the file in two copies. A business keeps it on site and hands it to a new owner or operator. A tenant can ask for a copy. For an off-grid system, add the inverter, battery and generator data sheets: they show which source feeds the site.
How often is an off-grid installation inspected again?
After the first inspection, the periodic visit depends on the type of installation, not on the grid. An off-grid farm is inspected as often as a farm on the grid.
Years between two periodic inspections
A major change or extension is inspected before it is used, but only the added or changed part. Adding a circuit to a home counts as a major change. For a business with urgent operational reasons, that check may follow within 30 days after use. The inspection at the sale of a home only concerns older installations that were never fully inspected.
Planning an off-grid site and want it right before the inspector comes? Call us or send a message.
Is an off-grid business installation inspected differently from a home?
Yes. A business, a farm or a school counts as a non-household installation, so it follows stricter rules. The periodic visit comes every 5 years instead of every 25.
The owner or operator also has more duties. They keep the file on site and give it to the inspector before each visit. They maintain the installation and log every test, such as the test of the residual-current devices. After a visit, they fix any faults without delay.
The school in Incourt is a good example. It is a private school for pupils aged 7 to 18, fed only by solar panels, a battery system and a generator. For a school, the off-grid system is simply its electrical installation. Our article on schools that run on their own power covers the rest of such a project.
What happens when the inspector finds a fault?
At the inspection before use, the installation or the faulty part may not be used until it is fixed and inspected again. That is why the check belongs in the planning, not after the move.
At a periodic visit, you fix the faults without delay and take measures so they are no danger while you keep using the installation. A new visit by the same body follows within one year at the latest. After the sale of a home, the buyer has 18 months to fix the faults.
Our verdict
An off-grid installation is not a way around the rules. It swaps the grid rules for your own responsibility. If the plan is a self-built box that nobody wants to sign for, do not go off-grid with it. A design that meets the AREI from the first drawing costs less than a rebuild after a failed inspection.
What happens when you ask us about an off-grid system?
We start from what must keep running and plan the installation so it can be inspected.
- Step 1: You send us the facts. Your consumption, or a list of the planned loads, and your largest motors and machines.
- Step 2: We measure and calculate. Our engineering office calculates the panels, inverters, battery, generator and cables for your site.
- Step 3: Installation, and the inspection before use.
- Step 4: You follow it in real time. You see production, storage and consumption in the app.
- Step 5: The system grows with you. It can be extended with extra panels, storage or another energy source.
Our off-grid systems power homes, farms, schools and businesses without a grid connection. For the parts and how they fit together, read about the components of an off-grid system.
Frequently asked questions
Does my fire insurer need an inspection report for an off-grid installation?
Policies differ, so read the conditions of yours. The inspection is a legal duty anyway, and the report is the proof that the installation was safe when it started. Keep it in the file of the installation.
Does the VNR notification replace the inspection?
No. The notification tells the Flemish regulator that an island installation exists. The inspection checks its safety under the federal AREI. You need both.
Is a building without a grid connection allowed?
That is a question for your permit and your municipality, not for the installer. Ask it early. Our articles on a new building without a grid connection and off-grid for businesses go into the details.
Do I need a new inspection when I add batteries later?
A major extension is inspected before use, limited to the added part. Adding a circuit counts as a major change for a home. Ask your installer whether your extension is major before you switch it on.
Can I use a home battery for an off-grid home?
Only if it is built to form a grid on its own. Our article on which home batteries work off-grid explains the difference.
Want an off-grid installation that passes the inspection?
Tell us what must run on your site, and whether there is a grid connection nearby. One of our engineers will explain how the system, the earthing and the generator fit together, and what the inspector will look at.
Sources
- FOD Economie: AREI Book 1, installations on low and extra-low voltage (2026)
- FOD Economie: inspections of household electrical installations
- FOD Economie: inspections of non-household electrical installations
- Vlaamse Nutsregulator: direct lines, closed distribution grids and island mode
- Vlaamse Nutsregulator: glossary, island mode (eilandwerking)
- Fluvius: reporting a storage system