How far are electricity poles apart?

The route for an overhead electricity line is surveyed to provide a profile (gradients) of the route -including any obstacles (roadways, rivers, outbuildings, etc.). Wherever possible, individual poles are placed where they will cause the least obstruction to farmers' machinery, etc. Ideally, means utilising natural or man-made features -e.g. following hedgerows, stone walls, etc. But, ultimately, their locations and, therefore, their distances apart, depend upon ensuring that the conductor sag remains above the minimum safety clearance, allowing for changes in temperature, ice loading, etc., and taking into account the profile (gradients) of the land and obstacles along their route. This is determined by a combination of the heights of adjacent poles and their distances apart and gradients/obstacles between. For routes across open, flat, countryside, the poles are likely to be roughly equidistant but, for route profiles that vary considerably in height, with obstacles, these distances can vary considerably.