Dead-end/suspension composite insulators for overhead lines ≤ 75 kV

1.1

This Standard covers the requirements for dead-end/suspension composite insulators used on overhead distribution lines operating at nominal voltages up to and including 75 kV. Dead-end insulators support the line conductor horizontally. Suspension insulators support the line conductor vertically. Both are subjected to tensile and torsional loads.

These composite insulators are intended to operate in a service environment within a temperature range of –50 to 50 °C.

The main objective of this Standard is to define terms, prescribe test methods, and recommend acceptance or failure criteria. Clauses 4 to 8 specify the material, product qualification, construction and test requirements applicable to these insulators. Annexes D, E, and F provide examples of design, type, and sample/routine test reports.

1.2

This Standard deals with composite insulators having a core with metal fittings and a housing and sheds. The core has resin-impregnated glass fibres. The housing and sheds consist of elastomers (e.g., silicone, ethylene propylene). The metal fittings are aluminum, steel, or iron.

1.3

In this Standard, "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.