10 Important AREI Inspection Points: Identify, Avoid and Correct Them
Ten recurring checks for Belgian domestic installations, explained without an unsupported ranking, failure rate or cost promise.
These ten points are a professional checklist, not a statistical ranking. No authoritative nationwide source supports a failure percentage or this order. The actual report remains decisive.
1. Missing or Incorrect RCD (Residual Current Device)
AREI Article: Art. 4.2.4.3 (main RCD) / Art. 4.2.4.3b (30 mA group RCD obligation)
Description
An important inspection area is a missing, unsuitable or incorrectly rated RCD. For domestic installations, the AREI specifically places socket-outlet circuits, lighting, locations containing a bath or shower, washing machines, dryers and dishwashers behind a high- or very-high-sensitivity RCD. This does not establish a nationwide frequency ranking.
Why It's a Problem
The RCD is the most important personal protection device in an electrical installation. It detects fault currents (e.g. when current flows through the human body) and disconnects within milliseconds. Without RCD protection, there is a risk to life in case of insulation faults.
How to Fix It
- Derive the RCD type and protection combination from the expected residual-current spectrum, earthing system, manufacturer evidence and applicable special chapter. For charging points, assess the individual AC-circuit RCD together with smooth-DC fault-current protection; for inverters, use evidence for the exact variant.
- Maximum 8 final circuits per 30 mA RCD (AREI Art. 4.2.4.3b)
- At least one RCD rated at no more than 300 mA is required at the origin; domestic RCDs are at least Type A. Time-delayed or selective construction depends on project coordination and is not a universal Type A-S prescription.
Project-specific scope
Device, poles, board space, wiring and measurements determine the quotation.
2. Missing or Outdated Electrical Plans
AREI Article: Art. 9.1.2 Nr. 1 (single-line diagram), Art. 9.1.2 Nr. 2 (situation plan)
Description
The AREI requires a current single-line diagram and situation plan for every electrical installation. Often these plans are completely missing or don't reflect the current state of the installation — for example because circuits were added or modified after construction.
Why It's a Problem
Without current plans, neither the inspector nor an electrician can safely assess the installation. In emergencies (fire, accident), the documentation showing which switch supplies which area is missing.
How to Fix It
- Create or update the single-line diagram and situation plan
- Document all circuits, breakers, RCDs and consumers
- Plans must show the actual current state
Typical Costs
Verified inputs and circuit tracing determine the work; software does not replace a survey.
3. Faulty Earthing
AREI Article: Art. 4.2.3
Description
Earthing is part of the installation's protection concept. A measured resistance above 30 ohms is not automatically equivalent to missing earthing under Art. 4.2.4.3b; it triggers additional residual-current protection requirements. A defect exists, for example, when earthing is absent or damaged or when the protective arrangement required for the measured value is not provided. Loose connections and corroded protective conductors also require professional assessment.
Why It's a Problem
Without functioning earthing, metal enclosures can be live without the RCD tripping. This creates an invisible death trap.
How to Fix It
- Have the earth resistance measured
- Above 30 ohms, verify the supplementary Book 1 arrangement: at least two high- or very-high-sensitivity RCDs, no more than sixteen simple or multiple socket outlets per such RCD, plus the additional protection required for the other affected circuits
- Decide professionally whether to improve the earth electrode system, adapt the protective arrangement, or do both
- Check all earthing connections and tighten if necessary
- Inspect the earth conductor for corrosion
Typical Costs
Measurements, existing system, soil and professional work determine the remedy.
4. Missing Main Switch
AREI Article: Art. 5.3.5.1b (main load-break switch)
Description
Every electrical installation must have an all-pole main switch that can de-energise the entire installation. The main switch must be rated at least 40A (for standard dwellings).
Why It's a Problem
In an emergency, the entire installation must be switchable off with a single action — for example in case of fire, flooding or accident. A missing main switch can cost life-saving seconds.
How to Fix It
- Install an all-pole main switch of at least 40A before the first RCD
- The switch must be easily accessible (distribution board)
- For three-phase installations: use a 4-pole main switch
Typical Costs
Rating, poles, board space and alterations are project-specific.
5. Bathroom Zones Not Respected
AREI Article: Art. 7.1
Description
The AREI defines protection zones in the bathroom (Zone 0, 1, 2 and 3), in which only certain electrical devices are permitted. Common violations: sockets in Zone 0 or 1, missing splash protection, switches too close to the bathtub or shower.
Why It's a Problem
Water and electricity are a deadly combination. Bathroom zones ensure that electrical devices maintain a sufficient safety distance from water sources.
How to Fix It
- Relocate sockets and switches outside Zone 0 and 1 (minimum 60 cm from bathtub/shower)
- In Zone 2: only IPX4-rated devices (splash protection)
- Protect all bathroom circuits with a 30 mA RCD
- No junction boxes in Zone 0 or 1
Typical Costs
Position, route, finishes and equipment determine the work.
6. Cable Cross-Section Too Small for the Breaker
AREI Article: Art. 4.4.1 (overcurrent protection) / Art. 5.2.1.2 (cable selection)
Description
The circuit breaker (MCB) must match the cable cross-section. A common mismatch: a 20A breaker on a 1.5 mm² cable (which is only rated for 16A). The breaker then fails to protect the cable from overload.
Why It's a Problem
When a cable carries more current than it can handle, it heats up and can cause fires. The breaker must always be less than or equal to the cable's current carrying capacity.
How to Fix It
| Cable cross-section | Max. fuse (gG) | Max. circuit breaker |
|---|---|---|
| 1.5 mm² | 10A | 16A |
| 2.5 mm² | 16A | 20A |
| 4 mm² | 20A | 25A |
| 6 mm² | 32A | 40A |
| 10 mm² | 50A | 63A |
- Reduce the breaker to the correct value or
- Replace the cable with a larger cross-section
Typical Costs
Reducing protection and replacing conductors are different remedies.
7. Too Many Circuits Per RCD
AREI Article: Art. 4.2.4.3b (max. 8 final circuits per 30 mA RCD); Art. 5.3.5.2b (max. 8 sockets per final circuit)
Description
The AREI limits the number of circuits per 30 mA RCD to maximum 8. In older installations, all circuits often hang off a single RCD.
Why It's a Problem
When too many circuits are connected to one RCD, the probability of nuisance tripping increases (due to cumulative leakage currents). Additionally, a fault leaves the entire dwelling without power — not just the affected area.
How to Fix It
- Install additional 30 mA RCDs
- Distribute circuits logically (e.g. by floor or function)
- Maximum 8 circuits per 30 mA RCD
Typical Costs
Board space, allocation, rating and measurements belong in the quotation.
8. Missing Circuit Labelling
AREI Article: Art. 3.1.3.1 (identification of circuits)
Description
All breakers and RCDs in the distribution board must be clearly labelled. The labelling must indicate which room or appliance is supplied by the respective circuit.
Why It's a Problem
Without labelling, the correct circuit cannot be quickly switched off in an emergency. Clear identification is also essential for maintenance work.
How to Fix It
- Apply readable labels to all breakers
- Name by room and/or function (e.g. "Kitchen sockets", "Bathroom lighting")
- Labelling must match the single-line diagram
Typical Costs
Labels are simple; safely identifying unknown circuits may need a professional.
9. Cables Without Protection
AREI Article: Art. 5.2.2 (installation methods) / Art. 5.2.1.5 (mechanical protection)
Description
Electrical cables must be routed in protective conduit (empty tubes), cable trays or wall chases. Exposed cables without mechanical protection — such as surface-mounted or loose in the basement — are a violation.
Why It's a Problem
Unprotected cables can be mechanically damaged (nails, screws, rodents). Damaged cable insulation can lead to short circuits and fires.
How to Fix It
- Route exposed cables through cable trays (protective conduit)
- For surface mounting: use appropriate cable channels
- Seal wall penetrations with fire-stop collars
Typical Costs
Cable, environment, mechanical protection and building work define the solution.
10. Missing Surge Protection (SPD) for New Installations
AREI Article: Art. 4.5.1
Description
Art. 4.5.1 generally requires that persons and property must be protected against the harmful effects of overvoltages — according to good professional practice. In practice, an SPD (surge protection device) is required for new installations and substantial extensions. For existing installations, it is recommended but not explicitly required.
Why It's a Problem
Surges from lightning strikes or grid disturbances can destroy sensitive electronics. An SPD safely diverts surges to earth and protects connected devices.
How to Fix It
- Install SPD Type 2 in the distribution board (after the main switch, before the RCDs)
- With lightning protection: additionally SPD Type 1
- Regularly check the SPD status indicator (green = OK)
Typical Costs
SPD selection, coordination, connection and board alterations are project-specific.
Conclusion: The Self-Check as Planning Assistance
PlanElec flags some supported planning issues. It cannot detect physical defects; the self-check remains partial and is not official. Sources are AREI/RGIE Book 1 V06 and official domestic-inspection guidance, without a frequency ranking.
Related articles:
- Inspection Failed — What Now?
- 30 mA RCD: When Is It Mandatory?
- Cable Cross-Section and Breaker: The Right Combination
- Bathroom Cables and AREI Zones
Structure your project with PlanElec and use the self-check to prepare for professional review and the official inspection. Get started →