Technical writing tips – using symbols properly

Engineers like to substitute symbols for words.  For example, “V” for voltage, “I” for “current,” and “W” for power. Some of these symbols are commonly understood, especially by other electrical engineers reading your content. But sometimes they are confusing, either because they are not commonly used or understood by a specific audience or because they convolute the sentence that they are used in . . . .

It is probably okay to use electrical engineering symbols like “V” and “W” in a mod package or other kinds of technical writing because they are commonly used and generally understood. Some symbols are better than others, though. “W” is short for “watts” which is a unit of power. Power can also be understood as “joules per second,” which is the equivalent of one watt.

To give an absurd example that illustrates what not to do, someone may be tempted to write “19 joules/sec” instead of “19 watts” or “19 W.” No one except academics use “joules per second” or any variant of it. Stick with what’s common.

Always avoid using quotation marks, both single and double, for “feet” and “inches.” It’s confusing. It’s easy to make a typo. They are harder to read. They make it easier for the reader to confuse the two, especially when they are skimming your document. Also avoid abbreviating the words (i.e. “ft.”) to make your meaning clear.

Here are some examples that combine numbers and symbols:

Don’t use

1.5” conduit 

The bolt length is 3/16”.


Drill a ⅛” hole






The smallest conduit size is 3 in.


The cable length is 45 ft.

Use this instead

1.5-inch conduit


The bolt length is 3/16 inch.


Drill a ⅛-inch hole.


one foot, three inches


301 feet, 4 inches


The smallest conduit size is three inches.


The cable length is 45 feet.

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