Creating a Single-Line Diagram — Step by Step

What is a Single-Line Diagram?

A single-line diagram (Dutch: eendraadschema, French: schéma unifilaire, German: Eindrahtschema) is a simplified electrical schematic that shows the structure of your entire installation using standardized symbols. Unlike a wiring diagram that shows every individual conductor, a single-line diagram uses a single line to represent each circuit.

This document is mandatory in Belgium for every electrical inspection according to the AREI/RGIE regulations. Without a correct and up-to-date single-line diagram, you cannot pass your inspection.

Why is it Important?

The single-line diagram serves multiple critical purposes:

• Legal requirement — Mandatory for every electrical inspection in Belgium
• Safety overview — Shows all protection devices and their coordination
• Maintenance reference — Helps electricians quickly identify circuits and components
• Modification planning — Essential for planning future changes to the installation
• Property documentation — Required when selling a property

Important: The single-line diagram must accurately reflect the current state of the installation. Any modification to the installation requires an update to the schema.

Understanding AREI Symbols

The AREI/RGIE prescribes specific symbols based on the IEC 60617 standard. Here are the most important ones:

Protection Devices

• Circuit breaker (automaat / disjoncteur) — Protects against overcurrent
• Differential switch (differentieelschakelaar / différentiel) — Protects against earth leakage
• Fuse (zekering / fusible) — Traditional overcurrent protection
• Main switch (hoofdschakelaar / interrupteur principal) — Disconnects the entire installation

Consumers

• Socket outlet — Represented by a semicircle symbol
• Lighting point — Circle with rays or cross
• Fixed appliance — Rectangle with device designation
• Motor — Circle with M designation

Special Symbols

• Earth connection — Three horizontal lines of decreasing length
• Equipotential bonding — Connecting line with earth symbol
• Surge protector — Zigzag line with arrow

Step-by-Step Guide with PlanElec

Step 1: Define Your Installation

Start by mapping out your electrical installation:

1. Open PlanElec and create a new project
2. Define the rooms in your building (living room, kitchen, bedrooms, etc.)
3. For each room, specify the electrical components:
   • Number and type of socket outlets (single, double, with earth pin)
   • Lighting points (ceiling, wall, switched)
   • Fixed appliances (oven, hob, boiler, etc.)
   • Special circuits (EV charger, heat pump, solar panels)

Step 2: Configure Protection Devices

PlanElec automatically suggests appropriate protection:

• Main differential switch — Typically 300mA for the entire installation
• Additional 30mA differentials — For wet rooms and outdoor circuits
• Circuit breakers — Sized according to cable cross-section and circuit type
• Surge protection — If required by your installation type

You can adjust these suggestions based on your specific requirements or your electrician's recommendations.

Step 3: Review the Topology

PlanElec generates the circuit topology automatically:

• Circuits are grouped logically (lighting, sockets, dedicated circuits)
• Each circuit gets a unique identifier (e.g., A1, A2, B1, B2)
• The hierarchy from main switch to end consumer is clearly visible
• Cable cross-sections are indicated for each circuit

Step 4: Generate and Export

With a single click, PlanElec generates your single-line diagram:

• AREI-compliant layout — Horizontal main bus with vertical branch circuits
• Standard symbols — All symbols conform to AREI Table 2.23
• Automatic labeling — Circuit references, cable types, and protection ratings
• PDF export — High-quality document ready for your inspector

Common Mistakes to Avoid

1. Incomplete Circuits

Every consumer must be traceable back to the main switch through a clear chain of protection devices. Don't leave any "floating" connections.

2. Wrong Symbol Usage

Use only AREI-approved symbols. Common mistakes include using old DIN symbols or inventing custom notations. PlanElec ensures you always use the correct symbols.

3. Missing Information

Every circuit must show:

• Circuit reference number
• Cable type and cross-section (e.g., XVB 3G2.5)
• Protection device rating (e.g., 16A)
• Number and type of consumers

4. Outdated Schema

If you've made changes to your installation, the single-line diagram must be updated accordingly. An outdated schema will be rejected during inspection.

Tips for a Perfect Schema

• Keep it clean — Avoid unnecessary crossings and overlapping labels
• Be consistent — Use the same notation style throughout the document
• Include all circuits — Even small additions like a doorbell or garden lighting
• Date your document — Always include the creation/modification date
• Add your details — Include the address of the installation and the name of the creator

Let PlanElec Do the Heavy Lifting

Creating a single-line diagram manually can take hours and requires detailed knowledge of AREI symbols and regulations. With PlanElec, you can generate a professional, compliant schema in minutes.

• No CAD software needed
• No electrical engineering degree required
• Automatic AREI compliance
• Export-ready PDF documents

Create your single-line diagram now — it's free →