hand typing

Drafting IEC publications



23 Lists

23.1 Purpose or rationale

A list serves to subdivide information to aid understanding.


23.2 Title

Lists do not have a title. They may, however, be preceded by a title or introductory phrase.


23.3 Numbering and subdivision

Lists can be numbered or unnumbered. Lists can be subdivided.


See the examples below.



The following basic principles shall apply to the drafting of definitions.
a)   The definition shall have the same grammatical form as the term:
1)   to define a verb, a verbal phrase shall be used;
2)   to define a singular noun, the singular shall be used.
b)   The preferred structure of a definition is a basic part stating the class to which the concept belongs, and another part enumerating the characteristics that distinguish the concept from other members of the class.



No switch is required for any of the following categories of apparatus:

  • apparatus having a power consumption not exceeding 10 W under normal operating conditions;
  • apparatus having a power consumption not exceeding 50 W, measured 2 min after the application of any of the fault conditions;
  • apparatus intended for continuous operation.



Vibrations in the apparatus can be caused by

  • unbalance in the rotating elements,
  • slight deformations in the frame,
  • the rolling bearings, and
  • aerodynamic loads.


23.4 Referencing

The purpose of a list should be made clear by its context. For example, an introductory proposition or a subclause title can serve to introduce the list.

If cross-references to list items are necessary, a numbered list shall be used. Within a subdivision, each list item in a numbered list shall have a unique identifier. Numbering restarts at each new clause or subclause.


Use, for example, the following forms for references to lists:

  • "as specified in 3.1 b)";
  • "the requirements given in B.2 c)".