The most dangerous thing about an overhead power line is the gap. People assume electricity needs contact, and HSE’s guidance opens by correcting them: going close to a live overhead line can result in a flashover that may kill - touching the line is not necessary for danger. Electricity arcs across air to the highest thing in reach, and on a site that thing is a raised tipper body, a crane jib, a telehandler boom, or a lorry-mounted crane mid-lift. The second myth HSE buries in the same breath: electricity can bypass wood, plastic or rubber if it is damp or dirty - gloves and rubber boots are not a plan.
Fixed plant gets risk-assessed once; vehicles bring the hazard to the line. A tipper raising its body under a distribution line, a lorry loader slewing toward a span it cannot see against the sky, a combine or telehandler working a field headland - the pattern repeats across industries because the vehicle arrives with reach the site was never designed around. HSE’s vehicle-specific instruction is blunt: vehicles, plant, machinery, equipment, or materials that could reach beyond the safe clearance distance should not be taken near the line. Note the phrasing - “could reach”, not “will reach”. A body that can rise into the zone is excluded even if the driver promises to keep it down.
HSE’s first answer is avoidance: find out whether the work really has to be done under or near the lines, or whether it can be done somewhere else. Materials must not be placed near overhead lines, and temporary structures belong outside safe clearance distances. When no work or access is needed beneath the lines, barriers go up at the correct clearance distance to prevent close approach at all.
When passage beneath the lines is genuinely required, the site builds defined passageways: barriers, goal posts and warning notices. The goal-post arrangement - a rigid frame over the route, lower than the line by the safe margin - forces the vehicle under a physical ceiling before it can enter the danger area. HSE acknowledges field work can make barriers and goal posts impractical across open ground, and points them to gateways, tracks and access points instead - the pinch points where vehicles actually enter.
None of this works on estimates. The safe clearance distance beneath an overhead line is not printed on the pole and cannot be judged by eye from a cab - it must be ascertained from the Distribution Network Operator. The DNO is the only source of the true clearance figure for a given line, and HSE’s guidance names it as the authority at every stage: barriers at the correct distance, clearances for passageways, all of it starts with the DNO’s number. A site manager guessing clearance from a map or a memory is running an uncontrolled risk with a fatal failure mode.
If the task must happen under live lines, the controls stack up: barriers, goal posts and warning notices, with the clearance confirmed by the DNO. And HSE adds an engineering control fleets rarely consider: modification. Vehicles such as cranes, excavators and tele-handlers should be modified with suitable physical restraints so they cannot reach beyond the safe clearance distance - and measures must ensure those restraints stay effective and cannot be altered or tampered with. A slew or height limiter that an operator can override is not a restraint; it is a suggestion.
The transport operator’s exposure arrives in two directions. As the visiting carrier, your driver tips, loads or delivers on someone else’s site - and the duty to manage overhead lines belongs to the site, but the cab is where the consequence lands. Drivers need the briefing: never raise a body, crane or boom without knowing what is overhead, and treat a site with no visible line controls as a reason to stop and ask, not to proceed.
As the site operator - the depot, the yard, the waste transfer station - the duty is yours: survey the lines, get the DNO clearance, barrier what should not be approached, goal-post what must be passed under, and exclude any vehicle that could reach the zone. The waste and aggregates world learned this expensively with tippers; the guidance exists precisely because raised bodies and overhead lines keep meeting.
Put overhead lines on the site plan and the driver’s site induction. Give drivers one rule with no exceptions: look up before you lift - body, crane, boom or forks. Make “I couldn’t see the line” an unacceptable answer by making the lines visible: barriers, goal posts, warning notices, and marked routes. And keep the DNO contact details in the site file, because the clearance number expires the moment someone guesses it instead.
Electricity does not give second chances, and flashover does not need a mistake that feels dramatic - just a body raised a metre too far on a damp morning. The controls are old, cheap and proven. The only failing version is the one that was never installed.