Overhead line equipment on the UK rail network operates at 25,000 volts AC. Electricity at this voltage can arc across air gaps of up to 2.75 metres, meaning lethal contact does not require physically touching the wire. OLE is present on all electrified main line routes and any work within the arc distance requires a specific safe system of work. Unauthorised approach to OLE has caused instant fatalities on the railway. Every worker on an electrified route must understand and respect these hazards.
Key Hazards
Electrocution from direct contact with 25,000-volt overhead line conductors
Electrical arcing across air gaps of up to 2.75 metres causing fatal flashover
Equipment or materials raised into the OLE danger zone during work activities
Step and touch potential from fallen or damaged OLE wires on the ground
Control Measures
Maintain the minimum safe distance of 2.75 metres from all OLE conductors at all times.
Never raise any equipment, tools, scaffold tubes, or materials above shoulder height near OLE.
Obtain an OLE isolation or permit before any work that could encroach within the danger zone.
Treat all OLE wires as live at all times unless you hold confirmed isolation documentation.
Brief all workers on OLE locations, danger zones, and height restrictions before each shift.
Use height-restricted plant and equipment in OLE areas to prevent accidental contact.
Report any damaged, displaced, or fallen OLE wire immediately — stay at least 20 metres away.
Do not shelter under OLE structures during storms as lightning can energise metal supports.
Ensure all ladders, scaffold, and access equipment are positioned outside the OLE danger zone.
Emergency / Rescue
If an OLE wire is damaged or has fallen, stay at least 20 metres away and warn others. Call the signaller and electrical control immediately. Do not touch the wire, any metal in contact with it, or the rails. Shuffle away without lifting feet.
Remember
OLE carries 25,000 volts and can arc through the air to kill you at 2.75 metres distance.
You do not need to touch the wire to be killed — electricity jumps across air gaps at this voltage.
Never raise anything above shoulder height when working near overhead line equipment.
Treat all OLE as live at all times unless you personally hold confirmed isolation paperwork.
A fallen OLE wire energises the ground around it — stay 20 metres away and shuffle, do not walk.
OLE isolation must be formally arranged through the electrical control room before any work begins.
Applicable Legislation: Railways and Other Guided Transport Systems Regulations 2006 · Electricity at Work Regulations 1989 · Network Rail Standards · Health and Safety at Work etc. Act 1974