PURPOSE AND SCOPE

This document forms part of a suite of documents which define National Grid Transco’s (NGT) functional and performance requirements for new and modified plant and equipment.

This Specification defines NGT’s requirements for the design including site investigation, construction and testing of foundations for overhead line supports (lattice steel towers and/or steel poles) and is applicable to new construction, and upgrading of existing foundations.

For overhead lines designed in accordance with the requirements of BS EN 50341-1 (hereinafter referred to as Part 1) and BS EN 50341-3-9 (hereinafter referred to as Part 3-9), the appropriate cross-references to the applicable clauses in Part 1 and Part 3-9 have been included, in brackets, in the text of this Specification.

This document replaces NGTS 2.10 Section 502 for design of new foundations or where strengthening is required as a result of a strength assessment against NGTS 2.10 Section 502. It is an interim issue and is subject to review by NGT following a programme of research and development into the strength co-ordination between the supports and their foundations, the corresponding foundation strength (material) factors and the characteristic strength of the foundations