Striking an underground electricity cable during excavation can cause fatal electrocution, severe burns, and explosion. Cables may be at shallow depth, may have been diverted from their recorded positions, and can carry voltages from 230V domestic supplies up to 132kV high voltage transmission. This talk covers how to identify, locate, and safely work near buried electricity cables.
Key Hazards
Fatal electrocution from striking a live underground power cable
Severe arc flash burns from cable damage causing short circuit
Explosion and fire from high-energy cable faults igniting soil or gas
Cables at unexpected depths or positions differing from utility records
Control Measures
Obtain up-to-date utility records and cable plans before any excavation or ground disturbance.
Scan the dig area with a cable avoidance tool (CAT) and signal generator (Genny) before breaking ground.
Hand dig within 500mm of any identified or suspected cable position using insulated hand tools.
Never use mechanical excavation methods directly over or within 500mm of a known cable route.
Treat all cables as live until the asset owner confirms they are dead and earthed.
Brief all operatives on cable locations, depths, and the safe digging exclusion zones for each area.
Mark cable routes on the ground using spray paint, marker posts, or cable covers after detection.
Ensure the CAT operator holds a current competency card and has received refresher training.
Report any cable strike or near miss immediately and evacuate the area until declared safe.
Emergency / Rescue
If a cable is struck, move everyone away from the area immediately — do not touch the cable or the machine. Call 999 and the asset owner's emergency number. Keep all persons at least 15 metres from the strike point.
Remember
Always scan with a CAT and Genny before any excavation or ground disturbance begins
Hand dig with insulated tools within 500mm of any identified or suspected cable position
Treat every cable as live until the asset owner confirms it is dead and earthed
Never use mechanical excavation directly over or within 500mm of a known cable route
If a cable is struck, evacuate immediately and keep everyone at least 15 metres away
Applicable Legislation: Electricity at Work Regulations 1989 · HSG47 (Avoiding Danger from Underground Services) · Health and Safety at Work etc. Act 1974 · CDM Regulations 2015