What Does the Inspector Check During an Electrical Inspection?
Documentation, visual inspection, measurements — learn point by point what the inspector actually checks and measures during an electrical inspection in Belgium.
Three areas: documentation, visual inspection, measurements
The inspector checks your electrical installation in three consecutive steps. If the documentation is already missing, the inspection typically stops right there — it's an automatic fail.
1. Documentation
The inspector requires the following documents:
- Single-line diagram — present, complete, and up to date?
- Situation plan — floor plan showing sockets, switches, and lights?
- Conformity declaration from the installer?
- Technical data sheets — distribution board, RCDs, circuit breakers?
Warning: The most common reason for failing an inspection is a missing or incorrect single-line diagram. Without proper documentation, the inspector will in most cases not proceed to measurements.
2. Visual inspection
Next, the inspector visually checks the installation:
- Correct cable cross-section per breaker? (e.g. min. 2.5 mm² at 16A for socket circuits; for lighting 1.5 mm² at 16A is sufficient)
- 30mA RCD present for all socket circuits?
- Maximum 8 circuits per RCD?
- Bathroom zones respected? (Zone 0, 1, 2 per AREI Art. 7.1, zone definitions Art. 7.1.5)
- Earth connection present and accessible?
- All junction boxes closed?
- Cables properly secured and protected?
- Main switch present and freely accessible?
- Surge protection device (SPD) present? (Art. 4.5.1 requires general protection against overvoltages according to the rules of the trade — in practice, an SPD Type 2 is recommended)
3. Measurements
Finally, the inspector performs technical measurements:
| Measurement | Limit | Instrument |
|---|---|---|
| Earth resistance | ≤ 30 Ohm (Art. 4.2.4.3b; additional RCDs required if exceeded) | Earth resistance tester |
| Insulation resistance | > 0.5 MOhm | Megger (insulation tester) |
| Loop impedance | Depends on MCB rated current | Loop impedance tester |
| RCD trip time | < 300 ms at rated residual current I∆n, < 40 ms at 5× I∆n (per IEC 61008) | RCD tester |
| Voltage measurement | 230V ±10% | Multimeter |
Result
After the inspection, you receive an inspection report. For new builds and major renovations, the inspection must be passed before the grid operator activates the electricity connection. If deficiencies are found, you are given a deadline for corrections and must schedule a re-inspection.