10 Important AREI Inspection Points: Identify, Avoid and Correct Them

These ten points decide the outcome of a Belgian domestic inspection particularly often: RCD protection, plans, earthing, main switch, bathroom, cross-section and protection, number of circuits per RCD, labelling, mechanical cable protection and surge protection. For each one you get the rule from AREI/RGIE Book 1 version 06, the reason behind it and the right correction. The order is a professional checklist, not a statistic – no reliable official frequency ranking exists. Your actual inspection report remains decisive.

Editing and review: PlanElec team, 5 October 2026.

1. Missing or wrong RCD

AREI reference: Art. 4.2.4.3b (RCD at the origin and high-sensitivity group RCDs) / Art. 5.3.5.3 a (type)

What the inspector checks

At the origin of every domestic installation there is at least one RCD of at most 300 mA. Immediately after it comes at least one high- or very-high-sensitivity RCD (at most 30 mA) for sockets, lighting, rooms with a bath or shower, and the washing machine, tumble dryer and dishwasher. RCDs in domestic installations are at least type A; the one at the origin has a rated current of at least 40 A.

Why it matters

The RCD detects residual currents, for example when current flows through a body to earth, and disconnects the circuit. If it is missing or wrongly assigned, an insulation fault remains life-threatening.

How to fix it

• Add missing RCDs and assign the prescribed circuits correctly.
• At most eight final circuits per high-sensitivity RCD (Art. 4.2.4.3b).
• Derive the type from the fault current spectrum, manufacturer documents and the special chapter. For charging points, chapter 7.22 requires a dedicated RCD of at most 30 mA per AC circuit plus protection against faults with a DC component; for inverters, the documentation of the specific variant applies.
• Whether a time-delayed or selective RCD is needed follows from the coordination in the project, not from a blanket rule.

Effort

Device, number of poles, space in the board, wiring and measurements determine the quote.

2. Missing or outdated electrical plans

AREI reference: section 3.1.2 (diagrams and plans), Art. 9.1.2 no. 1 (single-line diagram) and no. 2 (situation plan)

What the inspector checks

The file of a domestic installation includes a single-line diagram and a situation plan that show the installation as built. In a conformity inspection, the report expressly certifies that the installation was carried out according to those plans (6.4.6.4, b.4). Often the plans are missing entirely or show the state before later changes.

Why it matters

Without up-to-date plans, neither the inspector nor an electrician can assess the installation safely, and in an emergency nobody knows which device supplies which area.

How to fix it

• Create the single-line diagram and situation plan, or update them to the actual state.
• Document all circuits, fuses, RCDs and loads.
• Briefly describe later non-significant changes and add them to the file (9.1.2 no. 7).

Effort

Starting data and the circuit tracing required determine the effort. The on-site survey is the electrician's job; software structures the result.

3. Faulty earthing

AREI reference: Art. 4.2.3.2 (earthing installations), Art. 4.2.4.3b (earth value and RCD layout)

What the inspector checks

Earthing is part of the protection concept. In a domestic installation the earth electrode resistance is below 100 Ω (4.2.3.2). A value above 30 Ω does not automatically mean faulty earthing: under Art. 4.2.4.3b it triggers a stricter RCD layout. There is a deficiency when the earthing is missing or damaged, the value reaches 100 Ω, or the RCD layout that belongs to the measured value is missing. Loose connections and corroded earthing conductors are assessed as well.

Why it matters

Without effective earthing, metal enclosures can become live in a fault without the protective device disconnecting reliably.

How to fix it

• Have the earth resistance measured professionally.
• Above 30 Ω, apply the layout of Art. 4.2.4.3b: at least two high- or very-high-sensitivity RCDs, each with at most 16 single or multiple socket outlets, and for the remaining circuits at least one RCD of at most 100 mA per circuit or group.
• Decide with the electrician whether to improve the earth electrode, adapt the protection layout, or both.
• Check all earth connections and inspect earthing conductors for corrosion.

Effort

Measured value, existing situation, soil and the work required determine the solution.

4. Missing main switch

AREI reference: Art. 5.3.5.1 b (main switch-disconnector)

What the inspector checks

Every main distribution board has a main switch-disconnector that disconnects all line conductors and, where applicable, the neutral at the same time. In domestic installations its rated current suits the installation and is at least 40 A. A grid operator's overcurrent device may perform this function if it is designed for isolation.

Why it matters

In a fire, water damage or an accident, the entire installation must be de-energised with a single action.

How to fix it

• Install an all-pole main switch-disconnector of at least 40 A, four-pole for a three-phase installation with neutral.
• Position the board so the switch is easily accessible without special tools (5.3.5.1 c).
• Existing installations: under part 8, existing main switches from 25 A may stay in service in the cases listed there (8.2.1 no. 4, 8.2.2 no. 4).

Effort

Rating, number of poles, space and board rework are assessed per project.

5. Bathroom zones not respected

AREI reference: chapter 7.1 (rooms containing a bath and/or shower)

What the inspector checks

Chapter 7.1 divides the bathroom into zones. Zone 0 is the inside of the bath or of a shower tray at least 10 cm deep; with a shallower tray or no tray, it extends up to 10 cm above the floor within 1.20 m of the fixed water outlet. For a shower, zone 1 extends up to 1.20 m around the centre of the fixed water outlet and up to a height of 2.25 m; for a bath, its outer edge forms the boundary. Zone 2 only exists for a bath: a further 0.60 m around zone 1. Typical infringements are low-voltage sockets in zone 0 or 1, junction boxes in zone 0 and distribution boards in zones 0, 1 or 2.

Why it matters

Water strongly reduces the body's resistance. The zones keep equipment as far from the bath and shower as its level of protection requires.

How to fix it

• In zone 1, only SELV sockets and SELV controls with the source outside zones 0 and 1, plus suitable permanently connected appliances (7.1.5.2 c).
• In zone 2, low-voltage sockets only with a very-high-sensitivity RCD or individually via an isolating transformer of at most 100 W (7.1.5.2 d).
• In zones 1 and 2, at least protection against splashing water (external influence AD4, table 7.3); for low-voltage sockets in zone 2, the table's footnote allows IPXX.
• All bathroom circuits behind an RCD of at most 30 mA (Art. 4.2.4.3b).
• Existing bathrooms whose installation started before 1 March 2025 may, under conditions, keep the former zone layout (6.5.8.1 no. 3).

Effort

Position, cable route, finishes and equipment determine the scope.

6. Cable cross-section too small for the fuse

AREI reference: Art. 4.4.1.4 with table 4.11 (rating by cross-section) / Art. 5.2.1.2 (selection of wiring)

What the inspector checks

The protective device must match the conductor cross-section. A classic error: a 20 A circuit breaker on a 1.5 mm² cable that may only be protected at 16 A. Socket circuits also need at least 2.5 mm² (5.2.1.2).

Why it matters

If a cable carries more current than it can handle, it heats up and can start a fire. The protective device must therefore never exceed the rating permitted for the cross-section.

How to fix it

Maximum ratings for domestic installations according to table 4.11:

• Reduce the protective device to the permitted rating or
• replace the cable with a larger cross-section.

The table gives maximum values. Installation method, grouping and ambient temperature can require a larger cross-section (4.4.1.4).

Effort

Reducing the protection and replacing the cable are technically different solutions with very different effort.

7. Too many circuits per RCD

AREI reference: Art. 4.2.4.3b (at most eight final circuits per high-sensitivity RCD); Art. 5.3.5.2 b (at most eight sockets per final circuit)

What the inspector checks

A high- or very-high-sensitivity RCD supplies at most eight final circuits. In older installations everything often hangs on a single device. Part 8 allows more circuits in existing old installations (8.2.1 no. 16, 8.2.2 no. 10); for new and significantly modified parts, the limit applies.

Why it matters

Many circuits on one RCD add up leakage currents and increase the risk of nuisance tripping. In a fault, a large part of the home also loses power at once.

How to fix it

• Add more 30 mA RCDs.
• Split circuits sensibly, for example by floor or function.
• At most eight single or multiple socket outlets per final circuit.

Effort

Board space, split, sizing and measurements belong in the quote.

8. Missing circuit labelling

AREI reference: Art. 3.1.3.1 (identification of circuits)

What the inspector checks

All protective devices in the board are clearly labelled, and the label shows which room or appliance each circuit supplies.

Why it matters

Without labels, nobody quickly switches off the right circuit in an emergency, and maintenance becomes guesswork.

How to fix it

• Fit all protective devices with durable, legible labels.
• Name them by room and function, for example "Kitchen sockets", "Bathroom lighting".
• Align labels with the single-line diagram: the same reference in the board, on the diagram and on the situation plan.

Effort

Labelling itself is quick; safely identifying unknown circuits is electrician's work.

9. Cables without adequate protection

AREI reference: Art. 5.2.2 (installation methods) / Art. 5.2.1.5 (mechanical strength, penetrations)

What the inspector checks

Every cable must be suitable for its installation method (5.2.2) and laid so that it keeps its mechanical strength. If it is particularly exposed to mechanical damage, it is armoured or specially protected (5.2.1.5). Typical infringements: cable types unsuitable for surface or open installation, cables hanging loose in the basement, or unprotected floor penetrations.

Why it matters

Insulation damaged by nails, screws or rodents leads to short circuits and fires.

How to fix it

• Check cable type and installation method against the methods permitted in 5.2.2; put unsuitable cables in conduit or trunking, or replace them.
• Protect exposed cables mechanically.
• Protect floor penetrations at finished floor level; conduits there protrude at least 10 cm above the floor (5.2.1.5).
• Design penetrations between rooms with very different humidity to prevent condensation.

Effort

Cable, environment, protection method and building work determine the execution.

10. Surge protection not assessed

AREI reference: Art. 4.5.1 (principle of surge protection)

What the inspector checks

Art. 4.5.1 requires people and property to be protected, according to good practice, against the harmful effects of overvoltages, for example from atmospheric phenomena or switching. The text does not prescribe a specific type of surge protective device. What matters is that the electrician assesses the risk and documents the chosen solution.

Why it matters

Overvoltages from lightning or grid disturbances destroy sensitive electronics. A surge protective device (SPD) diverts them to earth.

How to fix it

• Assess the risk: lightning protection system, supply, cable lengths, PV and charging point.
• Set type, location and upstream protection according to the risk assessment and manufacturer data; with external lightning protection, a type 1 lightning current arrester comes into play.
• Document the SPD on the single-line diagram and check its status indicator regularly.

Effort

Selection, coordination, connection and board rework are project-specific.

Conclusion: two passes before the inspection

Go through the ten points in two passes: first documents and references, then the actual condition, measured values and protective functions together with your electrician. A corrected drawing does not prove that a physical defect has been fixed; conversely, every completed correction belongs back on the diagram and situation plan. Mark every open point with its source and owner, and keep the dated version with the inspection report, measurement records and manufacturer documents.

PlanElec's AREI/RGIE self-check reports findings on the supported rules, such as RCD assignment and circuit protection, before the inspection body arrives. The physical condition and measured values are assessed on site by the approved inspection body. Sources are AREI/RGIE Book 1 V06 and the official page on installation inspections; they establish obligations, not a frequency ranking.

Related articles:

• Electrical Inspection Failed – What Now?
• A 30 mA RCD for Every Socket?
• Cable Cross-Section per Circuit Breaker
• Which Cables Can I Use in the Bathroom?

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