What of the weather? Wood pole line design and weather loadings

The most fundamental aspect of wood pole overhead power line design for the designer must be the appropriate weather conditions which will be seen for the lifetime of the line. In the UK, loadings have for many years been imposed in a very prescriptive manner, based purely on conductor size and voltage (i.e. OHL Regulations 1970 and its precursors). These loadings constrained the user to employ “factors of safety” for the structure components, thereby limiting the stresses in each component to a fraction of the stated ultimate capability of the component to a level which was thought “safe”, or maintained a satisfactory degree of reliability