A 30 mA RCD for Every Socket? The AREI Rule (2026)

Short answer: neither per socket nor per circuit

No. AREI does not require a dedicated 30 mA residual-current device (RCD) for every socket, nor a separate RCD for every socket circuit. In a new home, one high- or very-high-sensitivity RCD (30 mA maximum) protects the required final circuits together – up to eight final circuits per RCD (AREI Book 1, subsection 4.2.4.3(b)).

You count circuits downstream of the RCD, not sockets. A power strip changes nothing: it plugs into an existing socket and creates neither a new circuit nor its own protection.

This article covers domestic AC installations under Book 1, version 06, applicable since 1 April 2026. DC installations, swimming pools and other special installations have additional rules.

What AREI requires for a new installation

At the origin of the installation there is at least one RCD rated at no more than 300 mA. Immediately downstream follows at least one high- or very-high-sensitivity RCD, to which at least these circuits are connected (4.2.4.3(b)):

Each such RCD protects no more than eight final circuits. Six suitable final circuits can therefore sit behind a single 30 mA RCD. Two groups of three are a design choice for better availability, not an obligation.

Fixed appliances such as a refrigerator, electric cooker or electric heating may connect, per circuit or group, to an additional RCD at the origin. That is not a back door for putting sockets or lighting behind 300 mA – and washing machines, dryers and dishwashers are explicitly on the 30 mA list. Heating by resistors embedded in walls at more than 25 V AC gets its own RCD of no more than 100 mA.

In domestic installations the RCD must be at least Type A; the one at the origin has a rated current of at least 40 A (5.3.5.3(a)). When Type A is not enough is explained in RCD Type A or Type B.

Three "eight" rules that get mixed up

A living room with four double sockets can therefore be a single final circuit. Conversely, eight circuits behind one RCD are already the limit, even if each feeds only one socket. Appliances that need their own circuit under 5.2.1.2 do not belong in a mixed circuit.

Cable size and overcurrent protection

Socket circuits are run in copper of at least 2.5 mm² (5.2.1.2). Table 4.11 (4.4.1.4) limits their protection to 20 A with a circuit breaker or 16 A with a fuse. That is a ceiling: installation method, grouping, ambient temperature, length and voltage drop can require a lower rating or a larger cross-section.

Earthing resistance above 30 ohms

The 30-ohm threshold does not replace the 30 mA rule – it tightens it. If the earth electrode's dispersion resistance is higher than 30 ohms, 4.2.4.3(b) requires:

• at least two high- or very-high-sensitivity RCDs,
• no more than sixteen single or multiple socket outlets per RCD (a fixed appliance, or a group operated by one common control device, counts as a socket outlet),
• for fixed-appliance circuits and all other circuits outside the 30 mA list, additionally at least one RCD of no more than 100 mA per circuit or group of circuits.

The sixteen counts socket outlets, not circuits; the eight-circuit limit still applies. A reading of exactly 30 ohms is not "higher than 30 ohms". In domestic installations the dispersion resistance must also be below 100 ohms (4.2.3.2). If that is not achieved, extra RCDs will not rescue the installation – the earthing itself has to be improved. More in Earthing in Belgium: TT or TN-S?.

Bathroom: 30 mA is only part of the protection

Circuits supplying a room with a bath or shower are protected by one or more high- or very-high-sensitivity RCDs installed outside the bathroom (7.1.4.3). SELV circuits, electrical separation and safety installations are exempt. The same RCD may also protect circuits in other rooms.

Zones 0, 1 and 2, permitted equipment, degree of protection and supplementary bonding (7.1.4.4) are separate requirements. A 30 mA RCD does not make a socket in a prohibited zone acceptable. For existing bathrooms whose execution began before 1 March 2025, 6.5.8.1 point 3 provides targeted deviations – not a rule for a new bathroom.

Existing installations: transition for work started before 1 June 2023

For existing parts of domestic installations whose on-site execution began on or after 1 June 2020 and before 1 June 2023 and that passed a conformity inspection under chapter 6.4, 6.5.8.1 point 1 provides a deviation; for older installations, the same deviations are in Part 8 (8.2.1 no. 16, 8.2.2 no. 10). Under that provision's conditions:

• socket and lighting circuits may remain in service without today's 30 mA protection, including after non-important modifications or extensions to those circuits;
• more than eight final circuits may remain behind a sensitive RCD;
• where the earthing resistance exceeds 30 ohms, instead of today's layout, one RCD for all lighting and, for each other circuit or group, one RCD with no more than sixteen socket outlets may remain in service.

This is not a blanket exemption for every older house. Start date and existing part must match; the approved inspection body is informed and records the deviation in its inspection report. For an important modification or extension of an old installation under Part 8, at least one RCD at the origin protects the whole installation (4.2.4.3(b)). New installations or projects started after 1 June 2023 cannot rely on this transition.

How to approach an existing installation:

1. Establish when and how far the original work was carried out.
2. Decide whether this is an existing part, a non-important or an important modification.
3. Document the deviation applied.
4. Compare single-line diagram, situation plan and distribution board with what is actually installed.

More RCDs does not mean: never a power cut

An RCD trips when it detects residual current. That is its job. Leakage currents, moisture or a faulty appliance will trip it. Several RCDs limit what goes dark – so that the fridge and the home office do not drop out together, for instance. Selectivity does not follow automatically; it depends on fault type, wiring and grading.

When surveying an installation, record not only "30 mA" but also type, rated current, number of poles and every final circuit actually connected. An outdated diagram easily suggests a correct count when neutrals or outgoing circuits in the board have since been rewired.

Plan and self-check in PlanElec

In PlanElec you record circuits, RCDs and sockets in the editor and export the single-line diagram and situation plan as PDF. The AREI/RGIE self-check flags, among other things, a missing main RCD of no more than 300 mA, socket circuits without a 30 mA RCD, more than eight final circuits per sensitive RCD and more than eight sockets or appliances per final circuit. The exact list of rules it checks is in What the self-check verifies. Measurements and the on-site inspection are done by the approved inspection body.

Further reading

• RCD Type A or Type B
• Sockets: how many per circuit?
• Create a single-line diagram
• Electrical inspection in Belgium

Legal basis: AREI/RGIE Book 1, version 06, subsections 4.2.3.2, 4.2.4.3(b), 4.4.1.4 (Table 4.11), 5.2.1.2, 5.3.5.2(b), 5.3.5.3(a), 6.5.8.1, 7.1.4.3 and 7.1.4.4. The official text published by the FPS Economy prevails.