Power Line Protection Zone: Widths by Voltage Class

What a power line protection zone is

The protection zone (OZ) is a strip of land along the line’s route within which construction, planting trees and other activities that could threaten the line’s safe operation are restricted. The zone’s width is measured horizontally from the projection of the outermost wires in their undeflected position.

Protection zone width by voltage class

Per the Rules for the Arrangement of Electrical Installations (PUE), 2026 edition, Table 2.5.32:

A sanitary protection zone is additionally regulated only for lines of 330 kV and above. For lines of 500 kV and above, no objects (buildings, structures, garages) may be located in the protection zone, except industrial buildings and structures on the territory of the electrical installation itself (for them the distance from the outermost wires in their most deflected position is 10 m).

Distance to objects already located in the protection zone

If an object (building, structure, garage) is located within the protection zone, PUE (2026 edition), Table 2.5.32, separately sets the minimum distance from the outermost wires, in their most deflected position, to that object:

Vertical clearances: wire height above ground and buildings

In populated areas, the minimum vertical distance from power line wires to the ground and to industrial buildings under normal line operation is set by PUE (2026 edition), Table 2.5.33:

Values are determined for the greatest wire sag under the temperature and mechanical load conditions set by PUE. These are vertical clearances, not to be confused with the horizontal protection zone widths in the tables above.

Rules for the Protection of Electrical Networks and PUE: what governs what

The zone widths in the tables above match the Rules for the Protection of Electrical Networks approved by Cabinet of Ministers Resolution No. 1455 of 27.12.2022 (the 1997 Rules, No. 209, are no longer in force). The Rules also set a 2 m zone for lines up to 1 kV and 30 m for 400 kV, as well as the procedure for work in the zone, while PUE regulates the line itself: clearances and distances to objects. The same zone widths are also given in PUE (2026 edition), Table 2.5.32. Each question needs its own document:

The figures are given as in PUE (2026 edition), Tables 2.5.32, 2.5.33 and 2.5.30; see also Distance Between Power Line Poles. The final distances for a site come from the design.

How much land the line strip takes: a worked example

The zone is measured from the outermost wires, not from the pole axis, so the total strip width equals twice the zone width plus the horizontal distance d (in plan) between the outermost wires. Example for a 110 kV line with an assumed d = 8 m: strip 2 × 20 + 8 = 48 m; from the line axis to the zone boundary 8 / 2 + 20 = 24 m, that is 2 × 24 = 48 m. Other voltage classes:

The horizontal distance d (in plan) between the outermost wires depends on the pole design and voltage and is taken from the line design; the value in the example is assumed.

A request worked through: a warehouse 18 m from a 110 kV line

A warehouse wall stands 18 m from the projection of the outermost wire of a 110 kV line. The checks go in order:

• 18 m is less than 20 m: the site lies inside the protection zone;
• under PUE (2026 edition), Table 2.5.32, the distance from the wire in its most deflected position to an object in the zone is at least 4 m, so the wire may swing towards the wall by no more than 18 − 4 = 14 m; the actual swing comes from the line calculation;
• placing an object in the zone is agreed with the line owner, and the owner is notified of planned earthworks and construction ten days in advance;
• in a populated area, above the site beside the warehouse the wire must be at least 7 m above the ground under PUE (2026 edition), Table 2.5.33; outside populated areas the requirement is lower: for 110 kV, 6 m in non-populated and 5 m in hard-to-reach terrain (Table 2.5.30). The height of loads and machinery is checked against that clearance.

Poles near roads and streets: distances and barriers under PUE

Under PUE (2026 edition), cl. 2.5.173, in a populated area the distance measured horizontally from the base of a pole to the ditch or kerb of the carriageway of a street or passageway must be at least 2 m, while PUE sets no distance to pavements and footpaths. The same clause says poles on city and village streets and roads should be guarded against vehicle impact (DBN B.2.2-12, DBN V.2.3-4). On motor roads covered by cl. 2.5.214 (public roads, access roads to industrial enterprises, on-farm roads), poles standing less than 4 m from the edge of the carriageway must be protected with Group I road barriers (cl. 2.5.220).

Crossings and close approaches to such a road follow Table 2.5.46 (cl. 2.5.216). Vertically, at least 7 m is needed from the wire to the carriageway surface for lines up to 110 kV, 7.5 m for 150 kV and 8 m for 220 kV. For wires with an aluminium part of less than 185 mm² this is also checked with a wire broken in the adjacent span, where the figure is 5.5 m for lines up to 220 kV (cl. 2.5.217). Horizontally, from the base or any part of the pole to the edge of the roadbed of a road the line crosses, the distance must be not less than the pole height; in constrained conditions, to the toe of the embankment or the outer edge of the ditch, it is 5 m for lines up to 220 kV on roads of categories IA, IB and II and 2.5 m (35–220 kV) on roads of other categories. More on crossings of lines with roads, railways and pipelines is in the article Power Line Crossings with Roads, Railways and Pipelines under the PUE: Poles, Clearances, Guards.

Where the line runs parallel to a road of any category, the base or any part of a pole must stand at least the pole height plus 5 m from the edge of the roadbed, and the outermost undeflected wire of a 35–110 kV line at least 15 m from the edge of the roadbed (4 m in constrained conditions).

What to prepare before ordering poles

To select poles that fit the zone and clearances, send us:

• the voltage class, the number of circuits and the wire arrangement;
• the route plan with the objects inside the zone and their distances to the outermost wires;
• the tallest objects under the line and at crossings: roads, buildings, other lines;
• site constraints for pole locations: buildings, utilities, plot boundaries.

If the strip is limited, consider a double-circuit pole: it takes less land along the route than two separate lines. Enter the main parameters (voltage class, number of circuits, wires, clearances) in the technical specification form and attach the route plan with the objects in the zone to your request; pole types are compared in the article Power Line Poles: Multi-sided, Lattice or Reinforced Concrete.