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Other factors



This page gathers up various non-technical aspects of high-voltage overhead power lines in the UK.

Holford rules

The so-called Holford Rules were developed by Lord Holford in 1959.

  1. Avoid altogether, if possible, the major areas of high amenity value, by so planning the general route of the line in the first place, even if the total mileage is somewhat increased in consequence.
  2. Avoid smaller areas of high amenity value, or scientific interest by deviation; provided that this can be done without using too many angle towers, i.e. the more massive structures which are used when lines change direction.
  3. Other things being equal, choose the most direct line, with no sharp changes of direction and thus with fewer angle towers.
  4. Choose tree and hill backgrounds in preference to sky backgrounds, wherever possible; and when the line has to cross a ridge, secure this opaque background as long as possible and cross obliquely when a dip in the ridge provides an opportunity. Where it does not, cross directly, preferably between belts of trees.
  5. Prefer moderately open valleys with woods where the apparent height of towers will be reduced, and views of the line will be broken by trees.
  6. In country which is flat and sparsely planted, keep the high voltage lines as far as possible independent of smaller lines, converging routes, distribution poles and other masts, wires and cables, so as to avoid a concentration or ‘wirescape’.
  7. Approach urban area through industrial zones, where they exist; and when pleasant residential and recreational land intervenes between the approach line and the substation, go carefully into the comparative costs of the undergrounding, for lines other than those of the highest voltage.

Commentary on the rules can be found in the following documents:

Avoiding bird collision

The article Between the lines on the Save Our Sandwell Canada Geese website goes into detail about measures to reduce the number of fatal collisions between birds and overhead power lines.