Symbols for one-line diagrams and situation plans
Electrical symbols for your Belgian one-line diagram and situation plan with a short explanation of each, from socket and two-way switch to RCD and earthing separator.
Below are the electrical symbols you find on a one-line diagram (eendraadschema) and situation plan, with a short explanation of each. Most match table 2.23 of AREI Book 1 (chapter 2.13), a non-exhaustive list. For components it does not cover, such as a home battery or a surge protection device, Condui uses its own symbol.
Click a symbol to see its variants and a link to the related explanation.
Grid and earthing
Where power enters the home, the earthing, and the boxes and enclosures where cables meet.
Mains Entry
The starting point of your one-line diagram: the supply from the distribution grid. State the number of phases and the voltage, for example 1N 230 V, 3 × 230 V or 3N 400 V.
Backup Feed
A second power source, such as a generator or the backup output of a hybrid inverter.
Earthing
The installation's earth electrode, usually an earth loop under the foundations or an earth rod. Note the measured earth resistance.
Earthing Separator
The earthing separator disconnects the earthing conductor from the main earthing terminal so you can measure the earth electrode's resistance.
Distribution Panel
The switchboard and distribution board where circuit breakers and RCDs feed the circuits. On the situation plan it shows where the board is located.
Junction Box
A junction box or branch box where cables are connected or branched.
Junction Panel
A junction cabinet: a larger enclosure where several cables are connected or distributed, without protective devices.
Terminal Strip
A terminal strip, a row of terminals where conductors are connected through, for example in a distribution board or technical cabinet.
Protection devices
Devices that disconnect a circuit on overload, short circuit, earth leakage or overvoltage.
MCB (Circuit Breaker)
A circuit breaker protects a circuit against overload and short circuit. State the poles, rated current and curve, for example 2P 20 A curve C.
RCD (Residual Current Device)
An RCD disconnects as soon as current leaks to earth. State the sensitivity, type and rated current, for example 300 mA type A 40 A.
RCBO (Combined)
An RCBO combines a circuit breaker and an RCD in one device for a single circuit. State the values of both.
Fuse
A fuse protects against overcurrent by melting. State the current and type, for example 16 A gG.
SPD (Surge Protection Device)
A surge protection device diverts short voltage spikes, for example from a nearby lightning strike, to earth.
Rotating switch
A rotary switch with several positions, for example as an isolator next to a heat pump or to choose between operating modes.
Source transfer switch
A source changeover switch selects between two supplies, for example grid and generator, so they are never connected to the installation at the same time.
Socket outlets
Socket outlets and their variants. The symbol shows earthing and child protection.
Socket with protective conductor contact and child protection
The usual socket in a Belgian home: with earth pin and child protection.
Double socket with protective conductor contact and child protection
Two sockets with earth pin and child protection in one flush box.
Socket with child protection
A socket with child protection but without an earth pin, as still found in older installations.
Double socket with child protection
Two sockets with child protection, without earth pin, in one flush box.
Modular socket
A modular socket on the DIN rail in the distribution board, for example to power a router or home automation module.
Socket with protective conductor contact
A socket with earth pin, without child protection.
Socket
The general symbol for a socket outlet. Add earthing, child protection or a switch with the variants.
Switches and controls
Everything that controls a circuit or appliance, from an ordinary switch to a relay.
Switch
An ordinary switch turns a light point or appliance on and off from one place. There are variants for 1, 2, 3 or 4 poles and with a pilot lamp.
Two-way Switch
A two-way switch controls a light point from two places, for example at the bottom and top of the stairs.
Cross Switch
An intermediate switch sits between two two-way switches so you can switch from three or more places, for example in a long hallway.
Dimmer
A dimmer adjusts the brightness of a light point.
Changeover Switch
A double switch controls two circuits separately from one place, for example the ceiling light and spots in the living room.
Pull Switch
A pull switch is operated with a cord, mostly seen in older bathrooms.
Contact
A separate contact, for example a door contact or an input of a home automation system.
Impulse/Push Switch
A push button sends a short pulse to an impulse relay or home automation input instead of switching the circuit directly.
Motion detector
A motion detector switches lights automatically when it detects movement. You may state the technology: IR, radar or a combination.
Smoke detector
A mains-powered smoke alarm, possibly interconnected with other alarms.
Relay
A relay or impulse relay in the distribution board switches a circuit on a control signal. There are variants for timer, time switch, impulse, thermostat and dimmer.
Lighting
Light points and luminaires, as you draw them per room on the situation plan.
Light Point
A light point is the connection point for a luminaire on the ceiling or wall. There are variants for emergency lighting and a built-in switch.
Spot Light
A spotlight or projector with a directed beam, with variants for a narrow and a diverging beam.
LED Fixture
An LED luminaire, for example an LED panel or LED strip.
Fluorescent Tube
A fluorescent luminaire or tube.
Fixed appliances
Household appliances and other fixed loads. The diagram then shows which circuit each appliance is on.
Stove
An electric cooker or hob, usually on its own circuit.
Oven
An electric oven.
Washing Machine
A washing machine.
Dryer
A tumble dryer.
Dishwasher
A dishwasher.
Freezer
A freezer.
Fridge
A fridge.
Microwave
A microwave oven.
Door Lock
An electric door lock or door opener.
EV Charger
A charging point for an electric car, on its own circuit.
Motor
An electric motor, for example for a gate, pump or roller shutter.
Device
The general symbol for a fixed appliance that is not in this list. Write the appliance name next to it.
Heating, hot water and ventilation
Water heaters, heating, heat pumps and ventilation.
Electric Boiler
An electric water heater, with a variant for a storage water heater.
Electric heating
An electric heater, such as a convector. There are variants with storage and with a built-in fan.
Ventilation
A fan or ventilation unit, for example a mechanical heat-recovery ventilation system.
Heat pump
A heat pump.
Gas heating
A gas boiler. Electrically this is the supply of the burner, pump and controls.
Oil boiler
An oil-fired boiler.
Pellet heating
A pellet stove.
HVAC source
A general heat source, with variants for the energy source (electricity, gas, liquid or solid fuel) and the type.
Signalling
Devices that give an audible signal.
Buzzer
A buzzer.
Bell
A bell, for example the doorbell.
Horn
A horn.
Siren
A siren, for example of an alarm system.
Home automation
Smart control of lighting, sockets and other circuits.
Domotica / Smart home device
A home automation control is drawn as a rectangle in two parts: the basic symbol, such as a switch or socket, at the bottom and the type of control at the top. There are variants for programmable, wireless, detection and push-button control.
Metering
Meters that record consumption or production.
Energy Meter
A kWh meter, for the grid operator's meter or a sub-meter, for example for a charging point.
Sources and conversion
Solar panels, batteries and devices that convert voltage or current type. State the characteristics of a source on the one-line diagram or in the installation file.
Transformer
A transformer, for example a bell transformer or an isolating transformer. There are variants for safety and short-circuit-proof transformers.
Rectifier (AC → DC)
A rectifier converts alternating current to direct current.
Inverter (DC → AC)
An inverter converts the direct current from solar panels or a battery to alternating current.
DC-DC Converter
A DC/DC converter, also called a chopper, converts a DC voltage to another level.
Solar panel
A photovoltaic panel or string of panels. State the number of panels and the peak power.
Battery
A home battery or other energy storage.
DC busbar
A DC busbar: a shared direct-current connection for panels, battery and inverter.