Understanding Electrical Drawings: A Deep Dive into Notes and Legends

Understanding the Essential Elements of Electrical Drawings: Notes, Legends, and Symbols

Discover the essentials of electrical drawings as we delve into the intricacies of notes and legends. Explore the various elements found in these drawings, including lighting fixtures, fire alarm systems, and electrical symbols.

Key Insights

  • All engineers typically include a notes and legends page in their electrical drawings, featuring general notes, and a variety of legends such as lighting fixtures and fire alarm systems.
  • Electrical drawings also contain an electrical symbol legend, notes about the electrical symbols, and information about lighting protection system installation.
  • Engineers make use of various graphical symbols in their drawings, such as drawing callouts, enlarged callouts, revision clouds, and revision triangles, all of which are critical to understanding modifications and revisions.

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Let's look at the first of our electrical drawings. This is the notes and legends page. Typically, all engineers have a notes and legends page.

The pages typically contain similar types of content. There are general notes, a lighting fixture symbol legend.

You can see fluorescent lights here, recessed lights here. These are lighting fixtures. There are fire alarm system legends, smoke detectors, and heat detectors.

In addition to lighting and fire alarm, there are also electrical symbol legends, single receptacles, and duplex receptacles. There are notes about the electrical symbols and notes about lightning protection system installation. There is a list of abbreviations provided by the engineer and graphical symbols.

You can see the drawing callout, an enlarged callout, a section callout, north symbol, revision cloud, and revision triangle. Again, whenever you make modifications to the set, you include revision clouds, which are numbered. Those numbers are also included on the right-hand side of the title block.

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And then we have the electrical sheet index. This is included at the front of the drawing set, but the engineers typically include their own sheet index on their first page. So there we have it, a review of electrical notes and legends.

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Al Whitley

AutoCAD and Blueprint Reading Instructor

Al was the Founder and CEO of VDCI | cadteacher for over 20 years. Al passed away in August of 2020. Al’s vision was for the advancement and employment of aspiring young professionals in the Architecture, Engineering and Construction (AEC) industries.

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