HSG47 is the HSE's guidance on avoiding danger from underground services during excavation. It sets out the practical steps for locating buried services, safe digging techniques, and emergency actions if a service is struck. Every person involved in excavation work must understand these practices. This talk summarises the key HSG47 requirements and how they apply to everyday digging operations on UK construction sites.
Key Hazards
Fatal electrocution from striking underground electricity cables during excavation
Gas explosion from machine damage to buried gas mains
Flooding from water main strikes causing excavation instability
Service strikes caused by relying on plans alone without physical detection
Control Measures
Obtain up-to-date service plans from all utility companies before any excavation begins.
Carry out a CAT and Genny scan of the full dig area and mark all detected services on the ground.
Dig trial holes by hand to confirm the exact position and depth of services shown on plans.
Hand dig within 500mm of any known or suspected service using insulated tools only.
Never use mechanical excavation methods directly over a detected service position.
Assume that uncharted services may exist — not all services appear on plans or detection scans.
Ensure the CAT operator is trained and holds a current competency certificate for the equipment.
Brief all machine operators and ground workers on service locations before digging begins each day.
Report any service strike or near miss immediately and evacuate the area until declared safe.
Emergency / Rescue
If a service is struck, evacuate the area immediately. For gas escapes, do not create ignition sources and call the National Gas Emergency number 0800 111 999. For cable strikes, keep 15 metres clear and call 999.
Remember
Obtain service plans and carry out a CAT and Genny scan before any excavation starts
Hand dig trial holes to confirm the exact position and depth of all detected services
Hand dig within 500mm of any known or suspected service using insulated tools only
Never use mechanical methods directly over a known or detected service position
Assume uncharted services may exist as not all are shown on plans or detected by scans
Applicable Legislation: HSG47 (Avoiding Danger from Underground Services) · Electricity at Work Regulations 1989 · CDM Regulations 2015 · Health and Safety at Work etc. Act 1974