TPC-15.11.08-10 - Overhead Line Structural and Materials & Hardware Working Group

Jennifer Havel

This guide provides general recommendations for maintaining wood poles and wood structures. The recommendations are based on sound asset management and engineering principles, safety and liability considerations and decades of field experience by many utilities. Included are technical explanations as required to cover: inspection of wood structures and attachments; supplemental preservative treatments; methods of restoring strength to pole sections weakened by decay, insects, woodpeckers and mechanical or other damage; wood structure system management.

This standard covers testing of line hardware used in the construction of overhead transmission and distribution lines, including line hardware, forged anchor shackles, shoulder live line extension links, and bolted dead end strain clamps.

This standard covers the requirements of inch-based hardware commonly used in wood pole overhead line construction. Metric hardware is not covered by this standard.

This guide consolidates useful information, methods, and reference materials that define the state of the art in the design of wood pole transmission structures, commonly in the 69 kV through 345 kV range, into one document. This guide addresses application of wood in transmission structures, characteristics of wood, methods of analysis, loadings, connections, non-wood members, erection and framing, quality assurance, electrical considerations, testing and maintenance.

This standard covers dimensions and strength requirements for anchor shackles used in overhead transmission and distribution line hardware.

Requirements for threaded zinc-coated ferrous strand-eye anchor rods and nuts commonly used in overhead line construction are covered in this standard.

Zinc-coated steel lag screws of the fetter drive, gimlet point, and twist drive types commonly used in overhead line construction are covered in this standard.

Zinc-coated ferrous clevises for spool-type insulators commonly used for supporting or dead-ending conductors in line construction are covered. The specifications for spool-type insulators used with these clevises are covered in ANSI C29.3-1986.

Requirements for mechanically testing load-rated line hardware for use on transmission and distribution facilities are described. Items specifically addressed in this standard include clevis and eye fittings, Y-clevis fittings, socket fittings, ball fittings, chain links, shackles, triangular and rectangular yoke plates, suspension clamps, and strain clamps. This standard is intended to cover routine acceptance testing. It is not intended for initial design tests.

Dimensions and strength requirements for shoulder live line extension links used in overhead transmission and distribution hardware are covered.

Dimensions and strength requirements for anchor shackles used in overhead transmission and distribution line hardware are covered in this standard.

The requirements of inch-based: (1) zinc-coated ferrous carriage bolts, machine bolts, double-arming bolts, double-end bolts, washer-head bolts, eye bolts, eye nuts, and washer nuts; (2) zinc-coated ferrous lag screws of the fetter drive, gimlet point, and twist drive type; (3) washers; and (4) staples, commonly used in overhead line construction, are covered. Metric bolts, nuts, and lag screws are not covered by this standard.

Test procedures for the slip and pullout strength certification testing of bolted dead end strain clamps for use on overhead transmission and distribution lines are covered by this guide.

Dimension errors in Table 5 for hex nuts have been corrected