Two-Way, Intermediate or Double Switch: Which One Belongs on the Single-Line Diagram?

Which arrangement matches how many control points?

The number of places from which you want to operate the same light point decides the arrangement. One place is a plain switch. Two places call for two two-way switches (wisselschakelaar, va-et-vient). Three or more places still use two two-way switches at the ends, with one intermediate switch (kruisschakelaar, permutateur) added per extra control point. The double switch falls outside that series: it operates two groups separately from a single place.

These functions are not trade slang — Table 2.23 of the AREI/RGIE, part of Chapter 2.13, gives each of them its own symbol. The same table applies to the single-line diagram and to the position plan of a domestic installation.

The AREI does not prescribe those conductor counts itself — they follow from the wiring principle. What it does require is that the single-line diagram state the type, cross-section and number of conductors of every electrical line, as well as the switches themselves (Sub-section 3.1.2.2 point a). A two-way arrangement drawn as an ordinary lighting circuit therefore omits mandatory data.

What is the difference between a two-way switch and a double switch?

Both look "double" on the shelf, yet they do the opposite. A two-way switch diverts one circuit to either of two outputs: paired with a second two-way switch it operates the same light point from two places. The double switch — Table 2.23's "single-pole changeover switch, double lighting" — operates two different circuits separately from a single place.

Practical consequence: a double switch never replaces a two-way arrangement, and vice versa. Fitting a double switch in a hallway that needs two control points gives you two rockers, each turning on its own lamp, not one lamp operated from both ends.

Mind the terminology as well. The Dutch AREI text calls the double switch "eenpolige omschakelaar (dubbele aansteking)" and the French RGIE text "commutateur unipolaire (double allumage)"; the intermediate switch appears as "kruisschakelaar" and "commutateur intermédiaire pour va-et-vient", while site language says permutateur. If you use different names, carry the Table 2.23 description into your legend — the regulation accepts any clearly identifiable symbol provided it is defined in the legend of the diagrams and plans (Sub-section 3.1.2.1 point a).

How many conductors does a two-way arrangement need?

Two strapping conductors run between the two two-way switches. Add to that the line conductor feeding the first switch, the switched conductor from the second switch to the light point, the neutral up to the luminaire, and the protective conductor where one is required. An intermediate switch does not change the principle: it is inserted into the straps, with two conductors on each side.

Two AREI rules govern the choice of those conductors:

• Cross-section. For electrical lines that are not an integral part of an appliance, a cross-section below 2.5 mm² is prohibited in principle. Table 5.1 (Sub-section 5.2.1.2) expressly allows 1.5 mm² for "electrical lines belonging to circuits without socket outlets" — precisely a pure lighting circuit with its switches.
• Colour. The green-and-yellow combination is reserved for protective and protective-bonding conductors; using green and/or yellow for the insulation of an active conductor is prohibited (Sub-section 5.1.6.2). Blue is reserved for the neutral in circuits that have one. Where a circuit has no neutral, the blue-marked core of a multi-core cable may serve another purpose — but never as a protective or bonding conductor. A strap may therefore be blue in a cable without a neutral, never green-and-yellow.

For cable types, Table 2.23 supplies its own worked examples: an XVB cable Cca with a stated number of conductors of a stated cross-section, or individual H07V-U conductors Eca in a conduit in a wall. Put the type and installation method actually used into the diagram; both are mandatory content of the single-line diagram.

Which symbol goes on the single-line diagram, and which on the position plan?

The symbol is the same — Table 2.23 covers both documents. The difference lies in the question each document answers, and above all in the reference.

The single-line diagram must show the switches, alongside junction and branch boxes, socket outlets, light points, fixed machines and appliances, the protective devices and the line data (Sub-section 3.1.2.2 point a). Each elementary circuit is identified by a capital letter; each light point, socket outlet and control unit receives a sequence number in the order in which it is met in the circuit, starting from the upstream overcurrent protective device (Sub-section 3.1.2.1 point a, Figure 3.1).

The position plan must give the location of those same switches (Sub-section 3.1.2.3 point a). And that is where the most frequently missed rule sits: each switch and each control unit is identified by the letter of the circuit it belongs to and by the sequence number of the light point or appliance it controls (Sub-section 3.1.2.1 point a, Figure 3.2). Two two-way switches jointly operating light point B3 therefore both carry the reference B3, not two consecutive numbers of their own.

That is exactly why the switch chain is not a cosmetic detail: without a recorded relationship between switch and light point, this reference cannot be assigned correctly. How the two documents interlock is set out in single-line diagram versus position plan.

When are push-buttons with an impulse relay better than an intermediate arrangement?

From three or four control points onward, an intermediate arrangement's wiring grows quickly: every extra place needs two straps out and back. Push-buttons wired in parallel on one shared control line, together driving an impulse relay, scale better. Table 2.23 section E carries both symbols: the "push-button" and the "impulse relay" (télérupteur).

Two things to keep in mind:

• The impulse relay sits in the distribution and switchgear assembly, so that is where it belongs on the single-line diagram, with its upstream protective device. It is not a property of the push-button in the hallway.
• The regulation explicitly accepts "control auxiliaries" and "electronic devices" as control devices, alongside switches and circuit breakers (Sub-section 5.3.3.2 point b). An impulse relay or a relay contactor is therefore not an exceptional construction — but it must comply with the relevant standards.

A related variant is the staircase timer or time switch; Table 2.23 provides a symbol for those too. The choice between impulse relay and timer is functional, not normative: the first holds until the next pulse, the second drops out after a set time.

May a switch be single-pole — and may it sit in the neutral?

Single-pole is permitted. Sub-section 5.3.3.2 point c states explicitly that, where no danger can result, not all active conductors need to be broken. A classic single-pole lighting switch breaking the line conductor falls within that.

The same provision immediately draws a limit: except for taking measurements, a single-pole control device is not placed in the neutral conductor. A single-pole switch mistakenly wired into the neutral leaves the appliance live while it appears to be off. That is a classic inspection finding, and it cannot be derived from a drawing — it must be established on site with the circuit de-energised.

Double-pole switching remains possible and is sometimes wanted, for instance for a permanently connected appliance that must be fully separable from the supply. Table 2.23 lists both the "double-pole switch" and the "double-pole two-way switch" for that. Pole count is therefore a property of its own, separate from the switching function — not a different arrangement.

How many light points may one switch chain feed?

Two AREI rules are commonly conflated here.

The limit of eight applies to socket outlets: the number of single or multiple socket outlets is limited to eight per final circuit (Sub-section 5.3.5.2 point b). A pure lighting circuit is not subject to it.

As soon as socket outlets, luminaires and other fixed appliances share the same final circuit, the rules for socket circuits apply — and then the text matters: "a single fixed appliance or a set of fixed appliances controlled by a common control device is treated as one socket outlet" (Sub-section 5.3.5.2 point b). Four spotlights hanging off one switch chain therefore count as a single unit in such a mixed circuit, not as four.

In addition, for dwelling units comprising more than two rooms and/or spaces, the circuits feeding the luminaires must be at least two separate circuits (Sub-section 5.3.5.2 point b). A single lighting circuit for a whole home is thus not a design choice but a shortcoming. The counting method in mixed circuits is worked through in sockets per circuit.

Where may the switch go in a bathroom?

For rooms containing a bath and/or shower, Sub-section 7.1.5.2 sets out volume by volume what is allowed. For control devices — an ordinary lighting switch among them — this gives:

A 230 V two-way switch therefore belongs outside volumes 0 and 1. A ceiling pull-cord switch is a common solution and has its own symbol in Table 2.23 ("single-pole pull-cord switch"), but it does not escape the volume rules: what counts is the volume the equipment itself occupies. The volumes and the associated wiring rules are covered in bathroom cables and AREI zones.

When does home automation replace an intermediate arrangement?

Once the same light point has to be operated from many places and in several scenes, a bus-based solution becomes more workable than an ever-growing intermediate arrangement. The regulation gives it its own section in Table 2.23: section J, "Home automation". The control unit is drawn there as a rectangle in two parts — the base symbol at the bottom (a switch, or a socket outlet with switch, for example) and the unit's control type at the top.

What home automation does not remove: every current-using appliance or electrical machine is operated through a control device, and that device is required even when operation depends on a relay, a thermostat or any similar organ (Sub-section 5.3.3.2 point d). The actuator in the board does not replace the required control device — it is one. What changes is the drawing: you document a control unit together with its control type instead of three intermediate switches in series.

Selection criteria and the usual pitfalls of mixed installations are covered in smart home and AREI.

How does the switch chain come about in PlanElec, and what changes on the diagram?

In the floor plan, the Switch chain tool links a switch to the luminaires it operates. PlanElec can propose a chain for the unassigned switches and luminaires of a room; a valid chain contains at least one switch and one luminaire, and a device cannot belong to two chains at once. Across storeys the chain stays coherent project-wide; each floor shows only its local segments and the continuation markers.

The switching function is derived from the chain: one switch gives on/off, two switches become two-way switches at both ends, and from three onward the first and last stay two-way while the ones in between become intermediate switches. Pole count is chosen separately — the two properties are only combined at drawing time. From three control points the double-pole variant is not rendered, because the RGIE symbol set holds no double-pole intermediate switch; that combination is then drawn as single-pole.

Push-buttons, dimmers and the double switch are deliberately not derived automatically. The double switch stays available as a manual choice precisely because it describes two separate circuits at one control point: you assign each luminaire deliberately to channel A or B.

Since the 30 August 2026 update, the link between a switch and its light points is stored durably and updates the single-line diagram as soon as the devices are assigned to a circuit. Luminaires not yet placed remain in the same switching group and join the chain automatically when placed. Automatic lighting only fills in missing light points — one per started 8 m², and per 6 m² in kitchens and bathrooms.

Step-by-step operation is described in the guide switch chains, circuits and cable routes.

What the AREI self-check does not do here

The self-check is orienting and evaluates only supported rules from the data entered. For switches specifically:

• It checks the plausibility of a control group: a group must contain at least one switch and at least one switched load. Groups without a switch, without a load, or with only one element are flagged.
• It does not check whether the chosen arrangement matches the intended operation. Two two-way switches in two different rooms form a technically valid chain and a rarely sensible one.
• It does not check whether a single-pole switch actually sits in the line conductor rather than the neutral. That does not follow from a drawing and must be established on site with the circuit de-energised.
• An impulse relay, a DIN-rail dimmer, a staircase timer or a twilight switch is not drawn in today's single-line diagram. They do not vanish silently: before export, PlanElec explicitly flags them as "distribution-board modules that cannot be shown", to be reviewed or removed.
• It replaces neither measurement nor inspection. The official assessment rests exclusively with an approved inspection body.

Related guidance

• AREI electrical symbols for both documents
• Creating a single-line diagram step by step
• Drawing a position plan
• Smart home and AREI

Open PlanElec and record your switch chains →

Basis: AREI/RGIE Book 1 V06 — Chapter 2.13 with Table 2.23, Sub-sections 3.1.2.1, 3.1.2.2, 3.1.2.3, 5.1.6.2, 5.2.1.2 with Table 5.1, 5.3.3.2, 5.3.5.2 and 7.1.5.2. The official text, the actual installed state and the approved body's inspection remain decisive.