Electricity emergencies and safety advice

If any changes in ground levels that are proposed in the vicinity of the overhead line might reduce safety clearances, please contact us first.

Safety advice for overhead lines:

• never use the base of a pylon (tower) or area immediately around it to store materials
• take care where radio aerials are attached to high vehicles
• take care when moving or tensioning electric fences, particularly in sloping areas
• don’t stand under the base of pylons (towers) during electrical storms
• do not direct jets of water or slurry at overhead power lines
• do not excavate where it would disturb the pylon (tower) foundations.

It's dangerous to climb on top of high vehicles parked or passing under overhead electricity wires.

Avoid operating tall equipment or lifting gear beneath an overhead electricity line.

No plant, machinery, scaffolding, or personnel should encroach within the safety zone of overhead conductor lines.

Take care when moving ladders, elevators, irrigation pipes or other long objects. They should be moved only when horizontal or in their lowest position.

Never reduce the clearance under overhead electricity lines by dumping or tipping waste material, erecting structures, buildings or hay stacks, or creating storage areas under lines.

No plant, machinery, scaffolding, or personnel should encroach within the safety zone of the overhead conductor lines.

Take care when moving ladders, elevators, irrigation pipes or other long objects. They should be moved only when horizontal or in their lowest position.

Never reduce the clearance under overhead electricity lines by dumping or tipping waste material. erecting structures, buildings or hay stacks, or creating storage areas under lines.

Flashovers 

Overhead electricity lines are normally bare (uninsulated) and if an object gets too close it is possible that a ‘flashover’ can occur, where electricity will jump over a distance to reach earth via the object. Flashovers can kill or cause severe shocks and burns to any person nearby.

In order to prevent flashover there are minimum safety clearances between overhead lines and the ground, roads, or objects on which a person can stand.

A flashover to a tree can cause a loss of supply to customers, a fire in the tree, or can lead to the tree itself conducting electricity.

Despite the dangers, we cannot actually prevent trees and vegetation being planted beneath our overhead electricity lines, as we do not own the land.

We have a duty to make sure that no tree comes close enough to an overhead electricity line to cause a flashover.

We employ specialist contractors to undertake vegetation management beneath our overhead electricity lines to make sure safety clearances are not infringed over a number of growing seasons.

All vegetation clearance work beneath and adjacent to overhead electricity lines must be carried out by specially trained staff.
 

Planting trees near overhead power lines or pylons

Only low height, slow growing species should be planted beneath overhead electricity lines, conductors, and towers.

If you are proposing planting in the area around a pylon (tower) base, you should consider the need to maintain safe vehicle access to the tower base for overhead line maintenance activities, and to prevent unauthorised access to towers.

Tree roots can disturb and prevent access to maintain underground electricity cables. Our prescribed planting distances between trees and buried services must be observed.

Please contact us for detailed technical advice before you finalise any landscape scheme.

Safety advice for leisure activities near overhead lines:

• never fly kites or model aircrafts near overhead power lines
• be careful to avoid lines when operating light aircrafts, hot air balloons, gliders etc
• fishing rods and poles made from carbon fibre and similar materials will conduct electricity. Fish at least 30 metres or more away from overhead lines
• do not light fires beneath overhead lines
• do not aim shotguns or pistols at overhead power lines.

Large birds, such as swans and geese, sometimes collide with overhead line conductors in poor visibility, resulting in their injury or death. 

Where bird collision has been identified as a problem, sometimes line-marking devices can be fitted to increase a line’s visibility. 

Overhead line towers are sometimes used by birds as convenient structures for roosting, often in significant numbers. 

Where bird fouling is a problem a number of methods to dissuade birds from roosting on towers may be used. The effectiveness of the bird scaring is monitored in conjunction with grantors and wayleave officers.

High-voltage overhead lines and certain items of substation equipment can generate noise. With lines, the level of this noise depends on the voltage. Sometimes a ‘crackling’ sound accompanied by a low-frequency hum can be heard. 

Noise from an overhead power line is produced by a phenomenon known as ‘corona discharge’. Overhead lines are built to minimise this, but surface irregularities caused by damage, insects, raindrops or pollution may locally enhance the electric field strength sufficient for corona discharges to occur. 

The noise levels associated with an overhead power line are weather-related and higher noise levels are likely to occur during: 

• damp weather conditions
• long dry spells, when airborne debris sticks to the lines (but this is washed away by a heavy rain shower). 

Where complaints about noise arise, we will investigate the cause of the noise and, if our equipment or practices are at fault, do all that we reasonably can to minimise the noise level. 

We also research lower noise alternatives that can be used when installing or refurbishing equipment. Where practical, we will deploy new techniques or equipment that produce less noise.

All our employees and contractors carry identification. Ask to see their identification if you are unsure about people visiting your land.

Don’t assume that delivery drivers and contractors know, or have remembered the route of, overhead electricity lines. Remind them – it could save their lives.