UK trade-and-hazard guidance by the Riskora Editorial Team
A single buried-service strike can be fatal, can knock out hundreds of properties, and routinely costs six-figure sums in reinstatement and damages. HSG47 'Avoiding Danger from Underground Services' is the binding HSE guidance and a RAMS that does not name it will not pass review. The key shift HSG47 introduced is treating service location as a planned three-stage process — plan, locate, dig — rather than a one-off CAT scan at the start of the works.
Build RAMS for this trade and hazardNo account required for the preview · No card required
Construction (Design and Management) Regulations 2015
Regulation 22 (excavation)
Practical and appropriate steps to prevent danger to any person from an underground cable or other service.
HSG47 Avoiding Danger from Underground Services (3rd edition)
All sections
Three-stage approach: planning (drawings, utility enquiries via LSBUD/Mallatite), locating (CAT and Genny, vacuum excavation), and safe digging (hand-dig within 500mm of any indicated service).
Provision and Use of Work Equipment Regs 1998
Regulation 5
Excavator quick-hitches, bucket attachments and ground-engaging tools must be maintained — broken teeth and worn quick-hitches contribute to over-dig.
Every UK RAMS reviewer applies the hierarchy of controls in the order below. Defaulting straight to PPE is the single most common reason a RAMS fails review.
1. Eliminate
Re-route the excavation to avoid known service corridors. Use trenchless techniques (directional drilling, mole) where alignment permits.
2. Substitute
Vacuum excavation in place of mechanical digging within 500mm of any indicated service.
3. Engineering controls
CAT4+ scanners with current calibration, Genny signal generator for traceable services, ground-penetrating radar for non-conductive services (water, drainage), service-marker tape detection.
4. Administrative controls
LSBUD utility search completed and drawings on site before any dig. Pre-start scan with CAT and Genny by competent operative (CSCS + utility detection training). Permit-to-dig issued by site supervisor. Hand-dig zone of 500mm around any indicated service, regardless of depth.
5. PPE (last line)
Hi-vis, helmet, gloves, safety boots. Insulated tools for any hand-dig near electric.
Submitting a RAMS that names CAT scanning but does not specify the depth-of-cover assumption or the hand-dig boundary. 'CAT scan to be completed' is not a control — the hand-dig protocol around indicated services is what prevents the strike.
An illustrative extract structured for principal-contractor review. Site-specific facts must be substituted and checked by a competent person.
LSBUD utility enquiry completed (reference LB2026-04-15-A). Drawings show 11kV electric, 75mm gas medium pressure and 100mm potable water in the works zone. Pre-start CAT4+ scan (calibration current to 12 March 2026) by trained operative will be supplemented with Genny signal injection on traceable services. Hand-dig only within 500mm of any indicated service, irrespective of depth on drawings. Vacuum excavation will be used to expose all services before mechanical excavation continues. Permit-to-dig issued daily by site supervisor and logged.
Daily CAT scanner pre-use check and battery test. Permit-to-dig signed at start of each shift. Photo log of exposed services. Toolbox talk before any change of dig position.
Are utility drawings sufficient on their own?
No — HSG47 explicitly states drawings are a starting point only. Drawings can be wrong by metres in plan and significantly in depth, and many services (older mains, abandoned cables, private supplies) are not on any drawing at all.
What is LSBUD?
LinesearchbeforeUdig — a free online portal that checks proposed excavation locations against the asset records of around 110 utility owners. It does not cover every owner, so direct enquiries to local DNOs and water companies remain necessary.
How close can a mechanical excavator dig to a known service?
HSG47 sets 500mm as the hand-dig boundary around any indicated service, regardless of depth on the drawings. Most principal contractors enforce this strictly.
Riskora prompts the right hazards for your trade, you confirm what applies on your site, and the document downloads to clean PDF in minutes.
Or browse all trade × hazard guides.