Power Line Crossings with Roads, Railways and Pipelines under the PUE: Poles, Clearances, Guards

Why a crossing has its own rules

The PUE chapter on overhead lines (2026 edition, cl. 2.5.1) covers AC lines from over 1 kV up to 750 kV.

Vertical distances are taken at the greatest conductor sag (highest air temperature or design ice load); over a railway the conductor is taken as heated by current (+70 °C where the loading is unknown), over a road or a pipeline it is not, unless a power-transfer mode with overheated conductors is provided (cl. 2.5.209, 2.5.216, 2.5.246, 2.5.160, 2.5.86). If the aluminium section is below 185 mm², distances are also checked for a conductor break in the adjacent span (mean annual temperature, no ice or wind).

The designer takes the final values for a specific crossing from the current text of the PUE. On pole types, see Power Line Pole Types by Purpose; on the protection zone, Power Line Protection Zone.

Railways: crossing angle, distances, poles

A line normally crosses a railway overhead (cl. 2.5.207); a cable is required on railways with especially heavy traffic and in justified cases (through an embankment, at a station). Crossings in station throats and where tension sections of the contact network join are prohibited. On electrified railways (including those to be electrified within 10 years) and for a 750 kV line over a public railway the angle must be close to 90° and not below 40°; for other railways it is not specified.

The pole base must stand at least the pole height plus 3 m from the building clearance gauge (the limiting outline for rolling stock, which nothing but the rolling stock may enter), cl. 2.5.208; on an electrified railway (or one to be electrified) the distance is counted to the axis of the contact-network poles. In cramped conditions it may be reduced to 3 m for lines up to 20 kV, 6 m for 35–150 kV, 8 m for 220–330 kV, 10 m for 500 kV and 20 m for 750 kV.

Poles bounding a span over a public, electrified or to-be-electrified railway must be tension poles of normal design, metal where traffic is heavy or especially heavy (cl. 2.5.210). In such a span a suspension pole is permitted between tracks with no regular passenger trains and at the edges of the railway bed: metal or reinforced concrete, with double supporting strings and fixed clamps. Guyed poles and single-post wooden poles are not allowed.

On lines with suspension insulators the tension strings in the span must be double, pin insulators are not allowed, and the reinforcement of reinforced-concrete poles and pole stubs that bound the span may not serve as an earth electrode (cl. 2.5.211). Distance from the conductor to the rail head on a non-electrified public railway, m (Table 2.5.45):

PUE (2026 edition), cl. 2.5.209, Table 2.5.45, which also gives values for non-public railways and a conductor break. For electrified railways the distance to the highest contact-network wire follows Table 2.5.35 (lines crossing each other).

Roads: poles, distances, signs

Cl. 2.5.214–2.5.221 cover public roads and access roads to industrial enterprises (categories IA, IB, II–V under DBN V.2.3-4) and the internal roads of agricultural enterprises. The crossing angle is not specified.

A road of category IA or IB is crossed between tension poles of normal design (cl. 2.5.215); with suspension insulators and an aluminium section of 120 mm² or more, the tension strings must be double. Suspension poles are permitted in that span outside the drainage ditch at the foot of the roadbed. At roads of categories II–V and internal agricultural roads the bounding poles may be light-design tension poles or suspension poles.

Road signs under DBN V.2.3-4 and DSTU 4100 must be put up on both sides of the line, and at crossings of lines of 330 kV and above also signs forbidding vehicles to stop in the protection zone; signs may not be hung on span wires inside the zone (cl. 2.5.218). Poles closer than 4 m to the edge of the carriageway must be protected from vehicle impact by group I road barriers (cl. 2.5.220).

At a crossing the base (or any part) of the pole must stand at least the pole height from the edge of the roadbed; on a parallel run, at least the pole height plus 5 m. Other distances, m (cl. 2.5.216–2.5.217):

PUE (2026 edition), Table 2.5.46. For 500 and 750 kV the table gives no values for a conductor break.

Pipelines and cableways

Cl. 2.5.241–2.5.248 cover above-ground and surface pipelines for gas, oil, oil products, liquefied hydrocarbon gas and ammonia, and cableways. A crossing angle close to 90° is recommended for pipelines for flammable liquids and gases and for passenger cableways (cl. 2.5.241). A crossing of a line of 110 kV and above with an above-ground or surface main or industrial pipeline for flammable liquids and gases is normally not allowed, except existing single-line surface main pipelines and technical corridors in an embankment (cl. 2.5.242). For newly built underground main pipelines for flammable liquids and gases the crossing angle at 110 kV and above is normally at least 60° (cl. 2.5.249), and distances follow Table 2.5.51 (cl. 2.5.250).

In the crossing span an above-ground or surface pipeline for flammable liquids and gases, unless in an embankment, must be covered by guards, so that no conductor can land on it, whether broken or intact, when a bounding pole falls. The guards go on both sides of the crossing at a distance from the pipeline equal to the pole height and must be wider than the projection of the extreme deflected conductors by 3 m for lines up to 20 kV, 4 m for 35–220 kV, 8 m for 330–750 kV (cl. 2.5.242).

Poles bounding the span must be tension poles of normal design; for steel-aluminium conductors (aluminium section from 120 mm²) or steel earth wires from 50 mm², light-design tension poles or suspension poles with fixed clamps are also permitted, except over passenger cableways. Conductors and earth wires over a pipeline for flammable liquids and gases must have no joints (cl. 2.5.243). Metal pipelines (not in an embankment), cableways and guards in the span must be earthed, with an artificial-electrode resistance of no more than 10 ohms (cl. 2.5.245).

Vertical distance from undeflected conductors to any part of the pipeline (embankment) or its protective devices in normal mode must be at least 3 m for lines up to 20 kV (1 m more to an embankment carrying a pipeline), 4 m for 35–110 kV, 4.5 m for 150 kV, 5 m for 220 kV, 6 m for 330 kV, 8 m for 500 kV and 12 m for 750 kV (cl. 2.5.246). Horizontal distances from the extreme undeflected conductor for approaches and parallel runs, Table 2.5.50:

PUE (2026 edition), Table 2.5.50. At a crossing the pole base must stand at least the pole height from the pipeline or its protective devices; in cramped conditions, 3 m (up to 20 kV) to 15 m (750 kV).

Example: a 110 kV line, a 26 m pole

A conditional example: a 110 kV line, a 26 m pole. At a non-electrified public railway the pole base stands at least 26 + 3 = 29 m from the building clearance gauge and the conductor at least 7.5 m above the rail head; at a crossing of a category II road the pole base stands at least 26 m from the edge of the roadbed and the conductor at least 7 m above the surface (5.5 m with a conductor break).

The pole height depends on the span and the sag; see Transmission Pole Height by Voltage Class and Distance Between Power Line Poles.

What to state in the request

To choose poles for a crossing, state what the line crosses (road category, railway traffic and electrification, pipeline type and pressure), the voltage class, the conductor grade and section, the crossing angle, any cramped conditions and the pole height the distances are counted from.

Put what you know into the technical specification form, and we will clarify the rest.