International Standards and Conformity Assessment for all electrical, electronic and related technologies
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Drafting IEC publications



Writing equations & formulae

How to write equations and formulae

As far as possible, make use of the normal text editing options. However, the use of fractions, exponents, integrals and other mathematical elements will require a special equation editor.


Do not use graphics in equations, and never insert an equation or formula as a picture. Equations need to remain editable - once turned into a picture, they can no longer be modified.


Which equation editor to use

Since January 2018 Microsoft Equation Editor 3.0 is no longer integrated in Word. We recommend using the MathType software provided by WIRIS.


Important: Word offers an equation editor on the Insert tab.


Do not use this editor - it does not allow to define the style settings required for IEC documents (as defined below).


Working with Math Type

To create a new equation, click on the MathType tab in Word, and select Inline or Display from the Insert Equations group. Inline equations are inserted inline with text, Display equations are inserted on a new line.


To edit an existing equation, double-click on it. The MathType workspace opens. To quit the MathType workspace, click anywhere outside of the equation. You will be prompted to save your equation: click "save" in order to save your modified equation.



Configuring how equation elements are displayed

To comply with the IEC requirements, set the parameters in the MathType workspace with the values shown below. This configuration will remain valid during subsequent sessions.


1) In the menu bar at the top, select Styles > Define...


2) In the menu bar at the top, select Size > Define...


3) In the menu bar at the top, select Format > Spacing