Electrical Drafter how-to

How to Draw a Clear One-Line Diagram

One-lines show the power system.

Updated By the Career Education Institute Curriculum Team
Quick answer

One-lines show the power system. In short: start; add; add, then complete the remaining steps below.

Step by step

  1. Start at the utility.

  2. Add transformers.

  3. Add switchgear.

  4. Add panels.

  5. Label sizes.

  6. Check against calcs.

Safety reminders for electrical drafters

  • Use ergonomic setups
  • Follow code in drawings
  • Protect project data
  • Take screen breaks

One-line diagram · Panel schedule · Riser diagram · Schematic · Ladder diagram · Symbol legend: see the full electrical drafter glossary.

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