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How to Read Electrical Prints

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Print reading for electrical drawings can be challenging because you have to memorize and become familiar with electrical symbols. In addition, there are engineering symbols that have to be interpreted and memorized. Call the engineering firm listed on the prints to get clarification. Some prints are strictly one-line diagrams that constantly cross over one another. These lines sometimes seem to melt into one another. Get an additional set of prints to highlight all the electrical so you can see it clearly.

Find the print index on the cover page of the blueprints and write down the electrical print numbers found in the lower right-hand corner. Find the cover page that has the general notes and read them carefully; these are instructions for the project. Familiarize yourself with this entire sheet by associating the electrical symbols with their electrical components.

Find the first electrical print (there is no set order in how prints are categorized). The page the engineer puts first is usually the first electrical print. You can also identify the first print by locating the page that gives you further instructions for electrical installation, as well as instructions to change what is on the print. Use the page that has all of the symbols as a reference for all of the electrical prints.

Count every light fixture and match it to the letter on the fixture schedule. Total each light fixture on a separate sheet of paper. Identify all receptacle types using your symbols sheet. Count them separately. Write the receptacle numbers down and make sure you clarify all special-purpose outlets separately. Use the symbols sheet to identify special-purpose outlets.

Locate the page that has "The Panels and Service Written Thereon." This page will have critical instructions for safety and use of the electrical system. On this page, you will get instructions on where and how to install the electrical panels.


Always keep a print reading reference book with you until you are comfortable without one.

Use the scale located at the bottom of the prints. This is what you use for determining square footage.


Blueprints are the entire project on paper, so simple mistakes can translate into a lot of lost revenue for someone. Be careful in installing systems from prints; if you are not sure about something, do not hesitate to ask someone. Make sure that any book you buy has sample prints, as well as questions and answers at the end.