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29 Tables

29.1 Purpose or rationale

Tables are used when they are the most efficient means of presenting information in an easily comprehensible form.


29.2 Title

It is recommended to provide a concise table title.


29.3 Numbering and subdivision

Tables shall be designated "Table" and numbered. By default, tables are numbered with Arabic numerals, beginning with 1, and the numbering shall be continuous and independent of the numbering of the clauses and of any figures. A single table shall be designated "Table 1". However, tables may be numbered with a prefix where the prefix denotes the clause number, and the second number denotes the sequence of tables in the clause. The numbering system chosen shall be consistent within any given series.

Further subdivision [e.g. Table 1 a)] is not permitted. A table within a table is not permitted. Subdivision of a table into subsidiary sections with new column headings is not permitted.

It is often better to create several tables rather than trying to consolidate too much information into one table. The simpler the presentation, the better. Complex graphical representations within tables should be avoided.

If a very complex table is necessary, it can be better to include it as a software supplement to the document.

In annexes, the table numbering restarts and the number is preceded by the annex letter (e.g. Table A.1).


When a table is continued over several pages, it can be useful to indicate the continuation.



Table  x (continued)



Table x (1 of#)


The column headings together with any statement concerning units can be repeated on all pages after the first.


29.4 Referencing

Each table shall be explicitly referred to within the text.


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

  • "Table 3 lists…";
  • "See Table B.1".


29.5 Specific principles and rules

29.5.1 Notes to tables

Notes to tables shall be located within the frame of the relevant table and shall precede table footnotes. A single note in a table shall be preceded by "NOTE", placed at the beginning of the first line of the text of the note. When several notes occur in the same table, they shall be designated "NOTE 1", "NOTE 2", "NOTE 3", ... . The numbering restarts for each new table.

Notes to tables shall not contain requirements or any information considered indispensable for the use of the document. Any requirements relating to the content of a table shall be given in the text, in a footnote to the table or as a paragraph within the table.


Table 8 summarizes how to use notes and footnotes within documents.

29.5.2 Footnotes to tables

Footnotes to tables are numbered independently from footnotes to the text. They shall be located within the frame of the relevant table, and shall appear at the foot of the table.

Footnotes to tables shall be distinguished by superscript lowercase letters, starting with "a". The footnotes shall be referred to in the table by inserting the same superscript lowercase letter.


Footnotes to tables may contain requirements. Table 8 summarizes how to use notes and footnotes within documents.

29.5.3 Keys to tables

In tables, it is sometimes necessary to abbreviate words or references in order to save space or to improve readability. The meaning of such abbreviated terms shall be explained in a key. See Table 11 .


Table 11 – Example of a table with a key


Data object name

Common data class






The name shall be composed of the class name, the LN-Prefix and LN-Instance-ID according to IEC 61850-7-2:2010, Clause 22.



Data objects

Status information



Level of action reached






Start level set-point





Operate delay time (ms)



T:         Transient data objects
M/O/C: The data object is mandatory (M) or optional (O) or conditional (C)


29.5.4 Headings in tables

When tables display numerical values of quantity values, notations such as


tables display numerical values of quantity values


are very useful in headings of tables, especially when the measurement units are different. See 29.6, Example 2.


When the measurement unit is the same, whatever the quantity value, a suitable statement (e.g. "Dimensions in millimetres") can be placed above the right-hand corner of the table.


29.6 Examples



The layout of the different elements that can appear in a table

Dimensions in millimetres



Inside diameter

Outside diameter


l1 a





d2 b c


A paragraph containing a requirement.

NOTE 1 Table note.
NOTE 2 Table note.
a   Table footnote.
b   Table footnote.
c    Table footnote.



When there are several different units:



Linear density


Inside diameter


Outside diameter








When all the units are the same:


Dimensions in millimetres



Inside diameter

Outside diameter







Correct and incorrect table headers. Table cells shall not be split diagonally.