Passing Underneath Overhead Lines

Safely Passing Beneath Overhead Powerlines

Passing equipment or machinery beneath overhead powerlines should always be avoided wherever possible. However, if a route beneath a live line is absolutely unavoidable, strict controls must be put in place to reduce the risk of contact or electrical arcing.

This type of activity requires careful planning, physical controls, and constant monitoring.

Limit the Number of Crossing Points

The first rule is to keep the number of passageways to an absolute minimum. A crossing point should only be created if there is no safer alternative route.

Every additional crossing increases the likelihood of an incident, particularly where multiple drivers, vehicles, or items of plant are involved.

Define and Control the Route

The crossing route must be clearly defined and physically controlled. Vehicles and machinery must not be able to drift towards the overhead powerline.

This should be achieved by using:

• Fencing or rigid barriers to guide vehicles
• Clear approach routes that prevent deviation

Install Goalposts to Control Height

At both ends of the passageway, goalposts must be installed to clearly identify the safe height limit.

Goalposts must be made from rigid, non-conductive materials, such as:

• Timber
• Plastic or PVC pipe

These act as physical gateways and provide a clear visual warning to drivers before they pass beneath the line.

Alternative Controls for Wide Crossing Points

If the crossing is too wide for a solid goalpost, alternative controls may be required.

These can include:

• Tensioned steel wire that is correctly earthed
• Plastic rope fitted with high-visibility bunting

These controls must be positioned further away from the overhead line, ensuring that movement of plant or vehicles cannot pull, stretch, or displace them closer to the live wires.

Maintain a Safe and Stable Surface

The passageway surface must be level, compacted, and well maintained.

Uneven or poorly maintained ground can cause machinery to:

• Bounce
• Tilt
• Raise booms, jibs, or loads unexpectedly

This significantly increases the risk of breaching safe clearance distances.

Use Clear and Visible Warning Signage

Warning signs must be installed on the approaches to the crossing, beside the goalposts, and on both sides of the passageway.

Signs must:

• State the maximum safe clearance height
• Instruct drivers to lower jibs, booms, buckets, or tipping bodies

Ensure Visibility in Low Light or Poor Weather

If work is carried out during darkness or poor weather conditions, additional visibility controls are essential.

This includes:

• Illuminating warning signs
• Lighting the goalpost crossbar

These measures ensure the crossing point remains clearly visible at all times.

Inspect and Maintain Controls Regularly

Regular checks are essential. Barriers, goalposts, and signage must be inspected throughout the job.

They must remain:

• Upright
• Clearly visible
• Effective and undamaged

If any control is damaged or displaced, work must stop until it is made safe.