Preface

This is the second edition of CSA C411.4, Composite suspension insulators for overhead lines > 75 kV. It supersedes the previous edition, published in 1998 under the title Composite Suspension Insulators for Transmission Applications.

Scope

1.1
This Standard applies to suspension and dead-end composite insulators used on ac overhead transmission lines with a nominal voltage greater than 75 kV and a frequency not greater than 100 Hz.

1.2
The objectives of this Standard are to
(a) specify insulator characteristics (mechanical, electrical, and dimensional) and prescribe the conditions under which these characteristics are to be verified;
(b) specify test methods; and
(c) specify acceptance criteria.

1.3
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 (nonmandatory) to define their application.