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

Yes. IEEE calls it a single-line or one-line diagram. SLD is the usual abbreviation. This page generates that power-system figure, not a continuous one-line drawing of a face or animal.

How is an SLD different from a circuit or wiring diagram?

An SLD collapses three-phase power into one line and uses power-system symbols (transformer, bus, breaker). A circuit schematic uses electronics symbols (resistor, capacitor, IC). A wiring diagram shows physical wires and terminals. If you need a breadboard or PCB schematic, use the circuit diagram maker instead.

Can I make a blank single-line worksheet?

Yes. Ask for a blank unlabeled SLD with empty boxes for the source, transformer, bus, and feeders. The layout stays the same as a labeled map so students can fill ratings from memory.

Is an AI single-line diagram accurate enough for a permit?

No. Use it as a draft for study, slides, or a first sketch. Permit packages, arc-flash studies, protective-device coordination, and OSHA postings need a qualified electrical engineer and current as-built data. Always check voltages, kVA, and breaker ratings against your design.

Is the single-line diagram generator free?

You can describe an SLD and generate a labeled figure in the browser. Sign in to use credits, remove the watermark, and create more diagrams for coursework and drafts.

Engineering Tool

Single-Line Diagram Generator for Electrical One-Line (SLD)

Q: What is a single-line diagram?

A single-line diagram (SLD), also called a one-line diagram, is a symbolic map of a power system. One line represents all three phases. It shows how power flows from the utility or a generator through transformers, buses, breakers, and loads. It is used for design review, teaching, and high-level documentation — not as a substitute for a three-line schematic or a field wiring diagram.

Generate a labeled electrical single-line diagram (one-line / SLD) with utility, transformers, buses, breakers, and loads.

Utility, generator, and transformerBuses, breakers, and feedersIEEE / IEC one-line symbolsLabeled or blank versions for revision

Single-Line Diagram Generator

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Describe your SLD and click Generate

Single-Line Diagram Examples

Utility, generator, solar, and blank electrical one-line diagrams for study and teaching

View:

Utility to MCC

The classic facility map — incoming utility, transformer, main bus, and labeled feeder breakers.

SLDutilityMCC

Generator with ATS

Utility plus standby generator through an ATS — the backup layout used in hospitals and plants.

generatorATSbackup

Solar PV grid-tie

PV array to inverter to the building bus — a clean interconnection one-line.

solarinvertergrid-tie

Substation feeder

A small substation: incoming CB, bus, two feeders, and station service.

substation11kVfeeder

SLD symbols

The standard one-line alphabet — generator, transformer, bus, breaker, motor, load.

symbolsIEEElegend

Blank worksheet

The same layout with names removed — fill source, transformer, bus, and feeders from memory.

blankworksheet

What is a single-line diagram (one-line / SLD)?

A single-line diagram — also called a one-line diagram or SLD — is the simplest map of an electric power system. One line on the page stands for all three phases (or for supply and return in DC), so a whole facility, feeder, or substation fits on one readable sheet. Standardized symbols mark generators, transformers, buses, circuit breakers, disconnects, motors, and loads. Power flow is usually drawn from the top (utility or generator) down to the loads. This generator turns a description of that map into a labeled teaching figure. It is not a wiring diagram of every conductor, and it is not a continuous-line art drawing.

Single-line vs schematic vs wiring diagram

Single-line / one-line: one line = three phases; power-system topology, protection, and ratings.
Electronics schematic: resistors, capacitors, ICs — how a circuit works electrically, not a building feeder.
Wiring diagram: physical routing, wire colors, and terminals for installation.
Use this page for SLD / one-line power maps. Use the circuit diagram maker for electronics. Use the wiring diagram maker for physical connections.

Common single-line symbols

Generator: a circle, often with G or a sine wave.
Transformer: two overlapping circles (windings), labeled kVA and voltage ratio.
Bus: a thick horizontal bar that several feeders attach to.
Circuit breaker: a square or a break with an X, often labeled frame and trip.
Disconnect / isolator: an angled break in the line.
Motor: a circle with M; loads as labeled blocks or arrows.

How to describe an SLD, and an honesty note

Name the source first (utility voltage or generator kVA), then the transformer ratios, the main bus voltage, and each feeder (MCC, panel, motor HP). Ask for IEEE or IEC one-line symbols and a white background. These diagrams are AI-generated illustrations, so treat them as a strong first draft for class, slides, or a conversation with an engineer — not as a permit drawing, arc-flash study, or OSHA posting. Check every voltage, breaker, and transformer against your design notes. AI can mix electronics schematic symbols into a power one-line, omit a main breaker, or draw line-art instead of SLD symbols; reject those and regenerate with a tighter prompt.