Single Line Diagram (SLD) Generator

Draw a single-line electrical diagram in your browser — on a computer or a phone — then export it as SVG, PNG or PDF. Free, no sign-up, and nothing leaves your device unless you choose to share it.

Nothing here yet Tap Symbols below and choose one, or start from a template.

How to use it

  1. Tap or click a symbol to place it.
  2. Drag it to move. It snaps to the grid.
  3. Tap one terminal, then another to wire two symbols together. The terminals are the small circles on each side.
  4. Select something and use Edit to label it.
  5. Export as SVG, PNG or PDF.

Keyboard

Ctrl+Z
Undo
Ctrl+Shift+Z
Redo
Ctrl+D
Duplicate
R
Rotate 90°
Del
Delete, with its connections
arrows
Nudge one grid square
Shift+arrows
Nudge five
+ − 0
Zoom in, out, fit
Esc
Cancel a connection

On a touchscreen: pinch to zoom, two fingers to pan, double-tap a symbol to rename it.

What is a single line diagram?

A single line diagram is a simplified drawing of an electrical power system. Each three-phase circuit is drawn as one line and each item of plant as one standard symbol, so the structure of the system is readable at a glance without the clutter of every conductor.

It is the drawing an engineer reaches for first when working out how power flows, where protection sits, and what happens when something is switched out.

How to use this generator

  1. Pick a template, or tap symbols from the palette to place them.
  2. Drag symbols to arrange them — they snap to a 20 px grid.
  3. Tap one terminal, then another, to wire two symbols together.
  4. Select anything to give it a label and a rating.
  5. Press Check to catch unconnected symbols and repeated labels.
  6. Export as SVG to keep editing elsewhere, PNG for a document, or PDF to print.

Your work is kept in this browser as you go, so closing the tab by accident does not lose it. Nothing is uploaded unless you ask for a share link.

Frequently asked questions

Is it free?

Yes. No account, no watermark, no limit on how many diagrams you draw.

Does it work properly on a phone?

Yes. The symbol palette and the properties panel slide up from the bottom so the drawing keeps the full width, there is a fixed bar with the actions you use most, and you can pinch to zoom and use two fingers to pan. Connection terminals are enlarged on touchscreens, because a 7 px target is no use to a fingertip.

Which export should I use?

SVG if the drawing might need changing later — it is vector, so it stays sharp at any size and opens in Inkscape, Illustrator or most CAD packages. PNG for dropping into a report or an email; exported at double resolution so it does not look soft. PDF to print, fitted to A4.

Can I come back to a diagram tomorrow?

Yes, two ways. The editor keeps your current diagram in this browser and offers it back when you return. For anything you want to keep properly, use Save file to download it and Open file to load it again — that file is yours and does not depend on this site.

Is my diagram private?

It stays in your browser. Nothing is sent to the server unless you press Get share link, and then only that diagram is stored so the link works. Anyone with the link can view it.

Does it check that my design is correct?

No, and it would be wrong to suggest otherwise. Check looks for two drawing mistakes: symbols connected to nothing, and the same label used twice. It does not size cables, verify protection grading, or calculate fault levels. It is a proofreader, not an engineer.