UK trade-and-hazard guidance by the Riskora Editorial Team
Utility workers face a unique buried-services problem: they are often the only contractor on site who knows their own asset is there, but everyone else's asset is the strike risk. NJUG (National Joint Utilities Group) Vol 1 and Vol 4 set the industry interface standards, and HSG47 Avoiding Danger from Underground Services applies to every dig. RAMS for utility installations must address not only the planned alignment but the risk of striking competing utilities at the crossings — which is where most strikes happen.
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HSG47 Avoiding Danger from Underground Services
All
Plan-locate-dig three-stage approach. CAT and Genny scanning. Hand-dig within 500mm of any indicated service.
New Roads and Street Works Act 1991
Section 81 (relations with utility undertakers)
Cooperation with other undertakers. Notice of works. Reinstatement specification.
NJUG Vol 1 (Guidelines on the Positioning and Colour Coding of Utilities Apparatus)
All
Standardised colour coding (red electric, yellow gas, blue water, green telecoms) and depth/positioning conventions for utility installations.
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
Trenchless installation (HDD, mole, pipe-bursting) where the utility being installed and the host ground permit. Avoids the open trench entirely.
2. Substitute
Vacuum excavation (e.g. RSP Mts Dino) within 500mm of any indicated service.
3. Engineering controls
CAT4+ and Genny set with current calibration. GPR for non-conductive crossings. Service-marker tape and warning slabs above the new install.
4. Administrative controls
LSBUD enquiry minimum 4 weeks before dig. Direct enquiry to local DNO and water company for any high-voltage or high-pressure crossing. Permit-to-dig per shift. NRSWA-trained supervisor on site.
5. PPE (last line)
Hi-vis Class 2, helmet, gloves, safety boots. Insulated tools for any hand-dig near electric.
Failing to specifically address service crossings. Most strikes happen where the new utility crosses an existing one — not along the planned alignment. RAMS that address only the route and not the crossings will be rejected.
An illustrative extract structured for principal-contractor review. Site-specific facts must be substituted and checked by a competent person.
Installation of 90mm SDR 11 PE water main from chamber W1 to W2 (alignment Drawing W-001 Rev C). LSBUD search ref LB2026-04-22-B identifies 4 utility crossings: 11kV electric (Western Power Distribution, drawing ref WPD-2024-887); 75mm gas medium pressure (Cadent, drawing ref CAD-2026-119); BT trunk (Openreach drawing OR-25-3340); existing 100mm asbestos cement potable water (UU drawing UU-22-665). Each crossing will be exposed by vacuum excavation before the new main reaches it. Hand-dig only within 500mm of any indicated service. Crossings will be photographed, depth recorded and detail-marked on as-built drawings. NJUG Vol 1 colour coding observed for all warning tape and slabs above the new installation.
Pre-shift CAT scanner calibration check. Permit-to-dig signed daily. Photo log of every exposed crossing. Toolbox talk before each new section of dig.
Is LSBUD enough to find all buried services?
No — LSBUD covers around 110 utility owners but excludes many private supplies, abandoned cables and some smaller water and gas owners. Direct enquiry to the local DNO, gas distributor and water company supplements the LSBUD search.
What is the difference between Vol 1 and Vol 4?
NJUG Vol 1 sets positioning and colour coding for utilities. NJUG Vol 4 sets the safe-working interface between contractors of different utility owners — particularly important on jointed crossings.
Can vacuum excavators replace hand-dig?
Yes — vacuum excavation is recognised by HSG47 as a safer alternative to mechanical digging within the 500mm hand-dig zone. It is more expensive but faster than hand-dig and dramatically lower-risk.
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