Preface:

This is the third edition of CSA C22.2 No. 158, one of a series of Standards issued by the Canadian Standards Association under Part II of the Canadian Electrical Code. It supersedes the previous editions, published in 1987 and 1984.

Scope:

1.1
This Standard covers assemblies of wiring terminals and supporting blocks for copper conductors, copper and aluminum conductors, and aluminum conductors rated at a maximum of 1500 V and 2000 kcmil, intended to provide for the connection of wiring designed to be used in accordance with the Rules of the Canadian Electrical Code, Part I.

1.2
These terminal blocks are intended to support permanently and to insulate wire terminations and joints from each other and from the surface on which the terminal block is mounted, where the absence of such support or insulation could result in a hazard.

1.3
Terminal blocks can be of various designs, such as sectional, modular, or one-piece.

1.4
Terminal blocks can employ a combination of connectors.

1.5
In CSA standards, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; "should" is used to express a recommendation or that which is advised but not required; and "may" is used to express an option or that which is permissible within the limits of the standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.

1.6
The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only.