Creating a single-line diagram

Avenler calculates the single-line diagram from the distribution board data and the circuit list: from the supply through the main switch, the RCDs and the MCBs to the outgoing circuits, each with its designation, protection and cable. There is nothing to draw, and it is split into printable sheets with a title block.

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What is a single-line diagram?

A single-line diagram is a simplified picture of a distribution board: multi-core cables are shown as a single line, and it shows only what matters for operation and protection. The supply is at the top, below it the main switch, the residual current devices (RCDs) and the MCBs, and at the bottom the outgoing circuits, each with its designation, protection and cable. At a glance it shows which circuit is protected by which device, and what sits behind what.

When is it used?

When designing the board, so that the allocation of protective devices and circuits is easy to follow; for installation, because the board can be assembled from it; for checking, because gaps (for example too many circuits behind one RCD) stand out on the diagram too; and for later extensions or fault-finding, when it gives the one quick picture of the board.

How does it relate to the distribution board?

The diagram follows the contents of the distribution board: it shows the same devices as the enclosure's module positions. The board designer of Avenler shows the enclosure as module positions arranged in rows (1–6 rows, 6–36 modules per row), with fill bars. For each device you can specify which RCD or main switch it sits behind and which circuit(s) it feeds; a sub-distribution board appears as an outgoing branch from a device of the parent board, and on its own diagram as the supply.

How does Avenler create it?

The single-line diagram does not have to be drawn: the program calculates it from the board data and the circuit list, so it always shows the current state and cannot differ from the board.

1. Circuits. On the floor plan you assign devices to circuits; each circuit has a designation (for example F3), protection (for example B16) and a cable (for example NYM-J 3×1.5).
2. Distribution board. In the board designer you add the enclosure and the devices, or use Suggest from circuits to get a preview of an allocation, which you can accept or discard. The board can be linked to the distribution board symbol on the floor plan.
3. Checks. The designer's Checks panel runs rules: for example a missing RCD, missing or oversized protection, an overloaded circuit, or a device that does not fit in the enclosure.
4. Single-line diagram. The Single-line diagram button opens the calculated diagram. If there is an error in the board data or a circuit does not appear on the diagram, the program warns you. Low-current circuits are not shown on it.

What data can be entered?

• Distribution board: name, type (single-phase or three-phase consumer unit, meter/service cabinet, sub-distribution board), enclosure and size.
• Device: kind, label, catalogue item and its module data (rated current, tripping characteristic, RCD sensitivity and type), number of poles, phase, parent device.
• Circuit: designation, description, single or three phase, protection, cable.
• For sizing: the supply cable and its length, and for each circuit the power, cos φ, diversity and length. From these the program calculates, as an indication, the design current (Ib) and the voltage drop (ΔU) for each circuit, which also appear in the table of the single-line diagram.

What documentation can it produce?

The single-line diagram has its own print view: on A4 or A3 sheets, in portrait or landscape, with a standard title block. With many outgoing circuits the diagram breaks across several sheets, with a continuation mark on the busbar that crosses the sheets. Print / Save as PDF opens the browser's print dialog.

Further documents for the board are the schedules produced from the drawing: the circuit schedule (“for the board door”: protection, RCD, phase, rooms), the cable schedule and the bill of materials, also as XLSX or CSV.

What it cannot do

The single-line diagram cannot be edited by hand: you change the board data and the diagram follows. Sizing and board checks are indicative only; they do not replace the professional responsibility of the electrical designer or verification against the regulations in force.

Create a single-line diagram