IEEE C135.31-1988

C135.31-1988 is a technical standard for coated ferrous single and double upset spool insulator bolts used in overhead line construction. It addresses a specific hardware application in power transmission and distribution, where bolt materials and coating performance can affect durability, assembly, and service reliability. For engineers, buyers, and utility contractors, this standard helps define a common basis for selecting and specifying line hardware with consistent dimensions and material expectations.

About C135.31-1988

This standard focuses on the requirements for coated ferrous spool insulator bolts in single and double upset forms. In practical terms, it supports the engineering of attachment hardware that secures spool insulators on overhead line structures. C135.31-1988 is relevant where mechanical strength, corrosion resistance from coating, and repeatable fit are important to line construction and maintenance. As a product reference, it helps align procurement and fabrication with a defined technical specification rather than informal shop practice.

Where is C135.31-1988 used?

The standard is typically used in overhead line construction and maintenance work involving spool insulators on utility poles and related support structures. It may apply to hardware selection for power distribution lines, line rebuilds, and replacement programs where coated ferrous bolts are specified for exposed outdoor conditions. In these settings, C135.31-1988 provides a reference for matching the bolt type to the insulator assembly and for keeping field installations consistent across crews and projects.

Importance in practice

Using a defined standard for these bolts helps reduce variation in hardware performance and installation outcomes. For power and energy applications, that matters because incorrect bolt form, coating quality, or material choice can affect corrosion resistance, fit, and long-term reliability. C135.31-1988 supports clearer specification, easier inspection, and more dependable procurement decisions. It also gives engineers and contractors a common technical baseline when comparing replacement parts or planning line hardware assemblies.

• Coated ferrous construction
• Single and double upset forms
• Spool insulator hardware
• Overhead line applications
• Utility procurement reference