BUR/Specific Services/TBT-BUR-010

Working Near High Voltage Cables

Buried Services & Utilities › Specific Services › Working Near High Voltage Cables

All Categories/Buried Services & Utilities/Specific Services/Working Near High Voltage Cables

Working Near High Voltage Cables

Toolbox Talk Record

Ref: TBT-BUR-010  |  Issue: 1  |  Date: March 2026
PresenterProject
LocationDate

What?

  • High voltage (HV) underground cables carry electricity at 11kV, 33kV, 66kV, or 132kV and above.
  • Contact with an HV cable causes instant fatal electrocution and explosive arc flash with no warning.
  • HV cables may be found at depths from 450mm to over 1 metre, but depth is never guaranteed.
  • Cable records from the distribution network operator (DNO) must be obtained before any excavation.
  • HV cables can be identified by their larger diameter, red or black outer sheath, and warning tiles above.
  • CAT and Genny detection is essential but cannot distinguish between LV and HV cables underground.
  • A minimum exclusion zone of 500mm on each side of a known HV cable route must be hand dug only.
  • Mechanical excavation is prohibited within the exclusion zone around HV cable positions.
  • The HSE guidance document HSG47 sets out the safe digging requirements near all underground cables.
  • Only the DNO or their approved contractor may work directly on high voltage cable assets.

Why?

Instant deathHV cable strikes cause instant fatal electrocution and explosive arc flash that kills operators and nearby workers.
No second chanceUnlike many hazards, there is no recovery from an HV cable strike. The first contact is almost always fatal.
Legal dutyThe Electricity at Work Regulations 1989 and HSG47 require specific controls before working near any underground cable.
Do Don't
  • Obtain cable records from the DNO before any excavation work begins.
  • Scan with CAT and Genny to locate underground cables before each excavation.
  • Hand dig within 500mm on each side of any known HV cable position.
  • Look for warning tiles, marker tape, and cable route markers during excavation.
  • Brief all operatives on the HV cable locations marked on the site plan.
  • Stop work and call the DNO immediately if an uncharted cable is exposed.
  • Use insulated hand tools when hand digging near known cable locations.
  • Maintain the exclusion zone around exposed HV cables with barriers and signs.
  • Contact the DNO if you need to cross or work parallel to an HV cable route.
  • Report any damage to cable sheaths, warning tiles, or cable route markers.
  • DON'T use mechanical excavation within 500mm of a known HV cable position.
  • DON'T assume cable depth from records; actual depth varies significantly on site.
  • DON'T touch, move, or work on exposed HV cables under any circumstances.
  • DON'T rely on cable colour alone to identify voltage; always treat as HV.
  • DON'T excavate without obtaining cable records from the DNO in advance.
  • DON'T ignore missing warning tiles; cables may still be present below.
  • DON'T drive ground anchors, fence posts, or stakes near HV cable routes.
  • DON'T allow plant to track over known HV cable routes without assessment.
  • DON'T attempt to repair or re-route an exposed HV cable yourself.
  • DON'T use pointed tools such as pickaxes or forks near known cable positions.

See also: Underground Cables | CAT and Genny Safe Use
ebrora.com

RAMS Builder

Generate professional Risk Assessment and Method Statements in minutes. 10 document formats, site-specific content, instant Word download.

Learn More