The minimum distance we can leave between trees and the lines to ensure public safety depends on the voltage of the line, but is a minimum of 5 metres (16ft) to each side of distribution lines (11,000 and 33,000 volt lines). This is approximately the same as the length of an average saloon type car. As the voltages increase for transmission lines, these minimum distances increase. For diagrams and further details on clearances to different voltages, see the safety clearance page.
Prior to any cutting a tree patroller will visit site and survey the overhead line identifying any vegetation that infringes, or has the potential to infringe, the required safety distances. The tree patroller will then make contact with the relevant landowner and explain what needs cut. An agreement on how any timber or branches should be disposed of will be made at this stage.
We have both a legal and moral obligation to remove safety hazards from our overhead network. This includes any trees, hedges or other vegetation which could be climbed or could support a ladder, and are within the relevant safety distance.
NIE understand the concerns of our customers in relation to their property. NIE always strive to ensure that the most appropriate staff, vehicles and machinery are sent to each work site, and that the site is left in the manner requested by the customer. The cutting may be carried out by trained tree climbers, or by flail depending on the site conditions and extent of the cutting, and we will agree with the customer on the method of disposal for any timber or branches.