Working Near Overhead Power Lines — Keeping Trades Safe Under GS6 (2026)

Why Overhead Power Lines Are So Dangerous

The thing that catches people out is that you do not have to touch a power line to be killed by it. At the voltages carried on most distribution and transmission lines, electricity can arc — or "flash over" — across an air gap to anything that comes close enough. A scaffold pole, a raised tipper body or an excavator boom does not need to make contact: get within a critical distance and the current jumps the gap, through the machine, and to earth through anyone in the way.

Contact and near-contact with overhead lines is a leading cause of fatal electrocutions on site. The common factor in almost every incident is machinery: a raised excavator or crane jib, a telehandler boom, a scaffold tube being carried upright, a long ladder, a MEWP basket, or — very frequently — a tipper lorry raising its body to discharge a load directly beneath a line. The driver often has no idea the line is there until the body touches it.

Because the danger is invisible and the consequences are usually fatal, the law and HSE guidance focus on keeping plant, equipment and people a safe distance away in the first place, rather than relying on care in the moment.

The Legal Framework

Several pieces of UK law and guidance apply when you work near overhead lines:

• Health and Safety at Work etc. Act 1974 — the general duty to ensure, so far as is reasonably practicable, the health and safety of your employees and others affected by your work. Working near OHPLs without controls is a clear breach.
• Electricity at Work Regulations 1989 — these place specific duties around work on or near electrical systems, including the requirement to prevent danger from contact with live conductors such as overhead lines.
• HSE Guidance Note GS6 — "Avoidance of danger from overhead electric power lines". This is the key practical document. It sets out exclusion zones, clearance distances, barrier and goalpost arrangements, and the controls you should put in place. Following GS6 is the recognised way to demonstrate you have done what is reasonably practicable.
• Construction (Design and Management) Regulations 2015 (CDM) — OHPLs must be identified at the planning stage and managed through the construction phase plan and risk assessments.

GS6 Clearance and Exclusion-Zone Distances

GS6 sets out safe clearance distances that depend on the voltage of the line and how it is supported (wood poles versus steel towers). Where lines cannot be diverted or made dead, you must establish an exclusion zone around them using barriers, with defined crossing points if vehicles or plant need to pass underneath. The table below summarises the commonly used GS6 figures — always confirm the actual voltage and arrangement with the Distribution Network Operator (DNO) before work starts, as exact figures depend on the line.

These are guideline figures from GS6. The precise clearance for any given line depends on its voltage, sag in hot weather, and the type of work. The safe approach is always to assume the worst case and verify with the network operator. Never gamble on a distance — if in doubt, treat the line as live and dangerous and keep everything well back.

The Hierarchy of Control

GS6 follows a clear order of preference. Work through these in sequence rather than jumping to barriers as a first resort.

1. Divert or isolate the line

The safest option is to remove the hazard entirely. Contact the Distribution Network Operator (DNO) for the area, or National Grid for higher-voltage transmission lines, as early as possible in the planning stage. They may be able to divert the line, raise it, fit insulation, or — most usefully — make it dead for the duration of your work. This usually needs weeks of notice and may carry a cost, which is exactly why it has to be planned, not left to the day the job starts.

2. If the line stays live, create exclusion zones

Where the line cannot be diverted or isolated, you must physically stop plant and people getting too close. GS6 recommends:

• Ground-level barriers running parallel to the line on both sides, at the clearance distance set out above, so machinery cannot stray underneath.
• Goalpost barriers at any point where vehicles or plant must pass beneath the line, with a horizontal bar set at a safe height to act as a height restrictor.
• Bunting and warning signs — high-visibility bunting strung between goalposts and along barriers, plus signs stating the danger and the maximum safe headroom.
• Defined crossing points (gateways) — limit passage under the line to one or two clearly marked gateways rather than letting plant cross anywhere.

3. Control the work itself

Even with barriers up, the way the job is run matters. Brief everyone on site about the line, keep plant with raised attachments away from the crossing points, and ensure tipping, lifting and high-reach operations only happen well clear of the exclusion zone.

Planning and Site Survey

Most OHPL incidents trace back to a failure at the planning stage — nobody identified the line, or it was noticed but never made it onto the risk assessment. Before any work starts:

• Survey the whole site for overhead lines before mobilising plant. Walk the boundaries and look up — lines crossing the corner of a plot, an access track or a neighbouring field are easy to miss from the cab.
• Identify the owner and voltage by contacting the DNO. Do not guess the voltage from the look of the poles.
• Record every line on the risk assessment and method statement (RAMS), with the clearance distances and the controls in place.
• Mark lines on the site plan and brief them at induction. A line that is obvious to you may be invisible to a delivery driver arriving for the first time.
• Plan vehicle routes and tipping/loading areas away from lines, so plant never needs to raise an attachment beneath one.

Rules for Plant and Tipping

Tipper lorries and machines with raising attachments deserve special attention because they cause a disproportionate number of OHPL fatalities. A tipper body raised to full height under a line, or an excavator slewing with its boom up, can close the gap in a second.

• Never tip a load beneath or near an overhead line. Designate tipping areas well clear of any line and brief drivers on where they are.
• Keep booms, jibs and bodies lowered when travelling under a defined crossing point.
• Fit height restrictors via goalposts at crossings so over-height plant is stopped before it reaches the line.
• Use a banksman for any plant movement near a line, and keep the operator's sightlines clear.
• Treat low lines with extra caution — service drops to buildings can be much lower than the main run and are often unnoticed.

What to Do if a Machine Contacts a Line

If a machine touches or arcs to an overhead line, the situation is extremely dangerous — the machine and the ground around it may be live. The instinct to jump down and help is exactly what kills people. The agreed procedure is:

• Stay in the cab. If you are the operator and the machine is still in contact, remaining seated is usually the safest place, because you are not providing a path to earth.
• Try to break contact if you can do so safely — drive the machine clear of the line and away from the contact point if it will move.
• If you must get out (for example, the machine is on fire), jump clear — never step down. Land with both feet together and do not touch the machine and the ground at the same time. Then shuffle or hop away with feet together to avoid step-potential between your legs.
• Keep everyone else well back. The ground near the machine can be live for a significant radius. Stop anyone approaching to help.
• Call the DNO emergency number and 999. Do not assume the line is dead because contact stopped — many lines auto-reclose and re-energise. Only the network operator can confirm it is safe.

Brief every operator and groundworker on this procedure as part of your induction. In the moment, there is no time to work it out — it has to be a trained reflex.

Emergency Contacts

Make sure the relevant emergency numbers are on your site information board and in your RAMS before work begins:

• 105 — the national power cut and electricity emergency number, which routes you to your local DNO.
• Your area DNO emergency line — identify it during planning so it is to hand if a line is struck or damaged.
• 999 — for any contact incident or injury, alongside the DNO.

If a line is brought down or a machine remains in contact, treat the whole area as live, keep people back, and wait for the network operator to confirm isolation before anyone approaches.

Quick Reference: Overhead Power Line Safety Under GS6