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One-line diagram maker.

Describe the electrical source, voltage, protection, buses, transformers, feeders, and loads to create a one-line diagram. A one-line, or single-line, diagram shows a power system in simplified form for design, review, and documentation.

Single-line DiagramEnter to send

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See it work

One-line diagram maker examples.

Same tool, four requests. Every drawing below is a real render.

What you type
Draw a feeder distribution single line diagram with an 11 kV ring main unit, incoming and outgoing 630 A load-break switches, transformer VCB and protection CT, a 1000 kVA 11 kV/415 V transformer, and retail and office LV feeders.
Then tryAdd a second transformer feeder to the RMU.Change the transformer rating to 1600 kVA.
Single-line diagram: 11 kV ring main feeder
Single-line diagram · IEEE Std 315 + ANSI device numbering · schematex-sld

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The drawing

What a one-line diagram is.

A one-line diagram, also called a single-line diagram, represents an electrical power system with one line instead of drawing every conductor. It identifies sources, switching and protection, transformers, buses, feeders, and loads.

It is a system-level drawing for understanding power distribution. It does not replace detailed wiring diagrams, calculations, or review by the qualified people responsible for the installation.

Standard
IEEE Std 315 + ANSI device numbering
Engine
schematex-sld
Editable
Double-click text, drag nodes
Export
SVG · PNG · PDF
Single-line diagram: What a one-line diagram is
Who uses it

Who uses one-line diagrams.

Single-line diagram: Electrical engineersElectrical engineers

Substation and feeder arrangements with source voltages, transformers, protection, and outgoing circuits.

Single-line diagram: Facility teamsFacility teams

Switchgear maps that explain how transformers, mains, a bus tie, and plant feeders are arranged.

Single-line diagram: Solar installersSolar installers

Residential systems that connect a PV array, hybrid inverter, battery, utility service, and critical loads.

How it works

How to make a one-line diagram in three steps.

01

Describe it

One paragraph is enough to start.

“Draw a feeder distribution single line diagram with an 11 kV ring main unit, incoming and outgoing 630 A load-break switches, transformer VCB and protection CT, a 1000 kVA 11 kV/415 V transformer, and retail and office LV feeders.”
02

See the drawing

Drawn by the right engine.

Single-line diagram: 11 kV ring main feeder
03

Say what changes

Every edit keeps a version.

Add a second transformer feeder to the RMU.
V2 · DRAWN FROM V1, NOTHING RETYPED
FAQ

Common questions

What is a one-line diagram used for?

It communicates the major components and power paths in an electrical distribution system for design, review, operation, and maintenance.

Is a one-line diagram the same as a wiring diagram?

No. A one-line diagram simplifies the system to sources, protection, buses, feeders, and loads; a wiring diagram shows detailed conductors and physical connections.

What information should I provide?

Describe the source and voltage, major equipment, breaker or fuse ratings, transformers, buses, feeders, and loads.

Can it show solar, batteries, and generators?

Yes. Identify each source, its rating, the connection equipment, and the bus or loads it supplies.

Can a one-line diagram replace engineering review?

No. Use it as documentation and communication; qualified professionals must verify design, protection, ratings, and code compliance.

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Draw your first one-line diagram.

Free account, no card. Describe the source, protection, and loads.

Open the editor