Circuit structure: distribution, limits and dedicated circuits
How to group, label and limit circuits, including the 8-socket limit and the rules for lighting points.
Uitleg
This page summarizes AREI Book 1 rules about circuits, distribution and traceability. The main references are the definitions in 2.12, diagram requirements in 3.1.2, marking rules in 3.1.3, the residential RCD structure in 4.2.4.3, and dedicated circuits such as EV charging in 7.22.
Looking for the meaning of sockets, lighting, fixed appliances or EV chargers first? See Consumers.
In short
- An elementary circuit runs between protective devices or after the final overcurrent protection.
- A dedicated circuit supplies one or more specific consumers exclusively.
- Each elementary circuit gets a capital letter on the one-line diagram.
- Endpoints on the situation plan must be traceable through the same code.
- Systems such as EV charging require a dedicated circuit.
What is a circuit?
AREI defines an elementary circuit as the part of an installation between successive overcurrent protections, or the part after the final overcurrent protection. In a home this usually means one protected group with its wiring and endpoints.
A dedicated circuit is reserved for one or more specific consumers. This matters for heavy or special appliances: an unclear mixed circuit can create both safety and inspection problems later.
General circuit
Supplies several ordinary endpoints.
- For example sockets or lighting in one zone.
- A clear code on diagram and plan is important.
Dedicated circuit
Supplies a specific appliance or system.
- For example an EV charger, cooker or technical installation.
- Protection and cable choice follow from the specific load.
Codes keep diagram and plan together
For household installations, each elementary circuit is identified with a capital letter on the one-line diagram. Lighting points, sockets and control units are numbered from the circuit's overcurrent protection.
On the situation plan, each point follows the same logic: the circuit letter plus the number from the one-line diagram. This lets an inspector trace a point on the plan back to the protection in the board.
| Example | Meaning |
|---|---|
| A | Circuit A on the one-line diagram |
| A1 | First endpoint on circuit A |
| A2 | Second endpoint on circuit A |
| B1 | First endpoint on circuit B |
A symbol without a circuit is not a usable dossier
A socket or light point on the situation plan is only useful when it is clear which circuit and protection it belongs to.
Limits and distribution
AREI uses different limits depending on the subject. One important example is the residential RCD structure: the number of final circuits under sensitive RCD protection is limited, with specific exceptions for existing installations.
For sockets and heavy consumers, also consider load, cable section, protection and whether a dedicated circuit is required. The diagram must therefore show not only how many points exist, but what kind of points they are.
Counting sockets
Each final circuit is limited to 8 single or multiple socket outlets.
A multiple socket outlet counts as one multiple outlet. A double or triple wall outlet therefore does not automatically count as two or three separate sockets for this limit.
In household installations, sockets normally have an earthing contact connected to the protective conductor, except in the specific cases allowed by AREI.
A socket that supplies only one specific appliance, such as a cooker, compressor or welder, is not a general-purpose socket for this limit. Show its purpose on the one-line diagram and situation plan.
The former prescribed mounting height for surface-mounted sockets was removed on 1 March 2025. Choose the height according to good practice, external influences and the manufacturer's instructions.
Lighting points: no separate numerical limit
For a lighting-only final circuit, current AREI does not set a separate maximum number of lighting points. The often-mentioned limit of 8 applies to single or multiple socket outlets, not as a general limit for lighting points.
A lighting point is where a lighting appliance is connected. Several lamps behind the same connection point and control are normally documented as one lighting point. Separate connection points or separately controlled zones should be documented separately.
Homes with more than two rooms and/or locations must have at least two separate lighting circuits.
There is therefore no rule saying “maximum 8 lighting points per circuit”. The circuit must still be designed correctly: cable section and breaker must match, the total load and voltage drop must be acceptable, and the residual-current structure must be correct.
Sockets, lighting appliances and other fixed appliances may share a final circuit, except for fixed appliances that require a dedicated circuit. Such a mixed circuit follows the requirements for socket circuits. Under the AREI counting rule, a fixed appliance or a group of fixed appliances with one common control can be treated as one socket outlet.
1.5 mm² conductors are often used for lighting circuits, usually with a 16 A breaker. This is not an exemption from normal sizing rules: the correct section also depends on installation method, length, load and protection. Do not automatically fit a heavier breaker just because a circuit has many lighting points.
Fixed appliances and dedicated circuits
Not every fixed appliance needs its own circuit. AREI does set a clear boundary for fixed appliances with a fixed location.
The following require a dedicated circuit:
- washing machine;
- dishwasher;
- tumble dryer;
- electric cooker;
- electric hob;
- electric oven;
- any fixed appliance or machine with a rated power of at least 2600 W;
- fixed electric heating, through one or more dedicated circuits.
Smaller fixed appliances, such as a refrigerator, extractor hood or lower-power ventilation unit, may use an ordinary or mixed final circuit unless another rule, manufacturer's instruction or design choice requires a separate circuit.
EV charging as a clear example
AREI is explicit for charging equipment: each connection point gets a dedicated circuit. Each dedicated AC circuit is individually protected by residual-current and overcurrent protection, subject to the specific conditions for charging equipment.
The detailed rules for charging equipment, RCD type and DC fault detection are in Special environments.
In Condui
Use dedicated circuits for systems that need to be checked separately later: an EV charger, PV connection, battery, cooker, heat pump or large fixed appliance. This makes validation and export much clearer.