Safe Excavation Practices: Avoiding Utility Strikes

Utility strikes are costly, dangerous, and crucially, preventable. Whether you’re breaking ground for a driveway, a fibre rollout, or a major civil scheme, the UK has clear guidance and proven methods to keep people safe and assets intact. This post distils the essentials from UK regulations and best practice so you can plan, survey, and dig with confidence

Why Utility Strikes Happen

Most incidents trace back to one (or more) of these failures:

No or poor planning.
Out-of-date plans or incomplete utility searches.
Inadequate on-site detection before digging.
Unsafe excavation techniques in “tolerance zones”.
Poor supervision and change control.

HSE’s Core Guidance (HSG47) centres on three pillars:

Plan the work.
Locate and identify services.
Excavate safely.

The UK Framework (what you must know)

HSG47

Avoiding danger from underground services (HSE): The definitive guidance for planning, locating, and excavating near buried services. Use it to build your method statements and permits to dig.

PAS 128:2022 Underground Utility Detection, Verification & Location

The UK specification for utility surveys. It defines survey categories (Type D/C/B/A) and quality levels so everyone knows the confidence of the data they’re using.

CDM Regulations 2015

CDM 2015 states that clients, designers, and contractors must manage excavation risks through the project lifecycle (utility risks included).

NRSWA 1991 & Codes of Practice

Street works must be coordinated, permitted and controlled; utility plans and protection measures form part of that control.

GS6

Overhead power lines: If your work involves tall plant, loaders, cranes or tipper vehicles, treat overhead lines as a critical hazard and control with planning, goalposts, and exclusion zones.

Step 1: Plan Before You Plant a Shovel

Define the Dig Area Precisely: Drawings, red-lined sketches, and coordinates reduce ambiguity later.
Request Utility Plans Properly: Use LinesearchBeforeUdig (LSBUD) to capture the majority of UK asset owners in one request, then follow up directly with any non-members (e.g. smaller private networks). Keep evidence of all enquiries and responses.
Choose the Right Survey to PAS 128: Type D (desktop plans). Type C (site reconnaissance with plans). Type B (detection with tools such as CAT & Genny and GPR, quality-coded). Type A (verification via exposure/trial holes).
Write a Utility-Aware Method: Embed HSG47 controls (mark-up, trial holes, safe hand-digging) into RAMS and the Permit to Dig process.
Allocate Responsibilities (CDM): Clients ensure sufficient time/info; designers design-out utility risk where reasonably practicable; the principal contractor coordinates surveys, controls and briefings.

Step 2: Locate and Mark Out Services on Site

Brief the team on known and suspected services before any breaking ground.
Scan methodically. Use CAT & Genny for conductive utilities and GPR for non-conductive/complex corridors; repeat scans as the site changes.
Trial holes (Type A) to verify exact line and depth. Never rely on plans alone.
Mark clearly (surface paint/pins/flags) and maintain a live utility map that supervisors update during work.

Step 3: Excavate Safely (Tolerance Zones)

Hand-dig first within tolerance zones until the service is fully exposed; use spades/shovels (not picks or mechanical breakers) and dig with the blade parallel to expected cable runs.
Open, inspect, and support. Don’t leave a service bridging unsupported ground.
Avoid mechanical plant directly over services; use trenchless techniques only with specialist planning and monitoring (moling/boring can displace soil into adjacent assets).
Control changes. If alignment, depth, or plant choice changes, stop and re-authorise the permit.

Special Case: Overhead Lines

Plan your routes to avoid travelling under lines; if unavoidable, set physical goalposts and signage, brief plant operators, and consider a banksman.
Assume lines are live; agree any isolations with the network operator well in advance; never store materials or raise booms in exclusion zones.

Permits, Briefings, and Supervision That Work

Permit to Dig: Issued only after plans, surveys, mark-up and trial holes are verified.
Point-of-Work Briefings: Show the marked services and photographs; toolbox talk daily where layouts shift.
Competence: CAT/GPR operators must be trained; allocate an Appointed Person for utility risk on complex digs.
Supervision: Maintain line-of-sight between the excavator and the exposed service; stop if visibility is lost.

HSG47 provides practical examples to build these controls into your system of work.

When Things Go Wrong: Strike Response

Stop work & evacuate to a safe distance. No engine restarts, no mobile phones near suspected gas releases.
Raise the alarm. Call 999 if there's a gas release, fire, explosion, or immediate danger to life/property; then contact the affected asset owner via their emergency number. (DNOs and gas networks provide 24/7 lines.)
Make it safe only if trained. Do not attempt repairs.
Secure the scene & record (photos, sketches, who/what/when).
Report where required under RIDDOR. Pipeline “dangerous occurrences” are specifically covered; follow HSE’s guidance to decide if your incident is reportable.

Street Works Context (Public Highways)

If you’re on the highway, your work also sits under NRSWA permit/coordination regimes. Coordination with the street authority, correct noticing/permits, and compliance with Codes of Practice are part of preventing strikes and managing residual risk.

Practical Checklist for Safe Excavation Practices

Before Site

LSBUD enquiry + direct requests to non-members, all logged.
PAS 128 survey specified and commissioned (Type B/A for excavation).
Updated composite utility plan created and briefed.
RAMS & Permit to Dig reflect HSG47 controls.
CDM roles clear; time allowed for surveys and trial holes.

On Site (Daily)

CAT/GPR re-scan of work area, mark-up maintained.
Trial holes at entry/exit points and along the route as needed.
Hand-dig in tolerance zones; insulated tools only.
Supervisor present during all exposure work.
Overhead line controls in place (goalposts, briefed routes, spotter).

If Struck or Suspected

Stop, evacuate, call 999 if gas/fire/explosion risk.
Notify asset owner; secure and record.
Consider RIDDOR reporting (pipelines/dangerous occurrences).

Specifications to Copy into Your Project Documents

Utility Survey Brief: Deliver a PAS 128:2022 Type B detection survey with Quality Levels assigned to all features, followed by Type A verification at all conflict points. Provide CAD and GIS deliverables, utility corridors, confidence codes, and annotated trial-hole photos.
Permit to Dig Gateway: No mechanical excavation within marked tolerance zones until the service is proven by Type A verification and signed off by the Supervisor.

Final Thoughts

Safe digging isn’t luck; it's a disciplined process. Start with the right information (LSBUD + PAS 128 surveys), verify on the ground (trial holes and mark-up), and only then excavate under tight controls (HSG47).

Build those steps into your CDM arrangements and your permits, and you’ll drastically cut the risk of hurting people or knocking Britain’s networks offline.

You can learn more about health and safety in construction in our informative blog post Construction Site Health & Safety Explained.

Why choose PIP Services for your health and safety consultancy?

We’re dedicated to providing the highest level of advice on all Health and Safety related matters and will assist companies in meeting their obligations. We offer a wide range of Health & Safety Services for a variety of clients. We represent many companies and deal with all of their Health & Safety matters.

We’re also an accredited CITB, NEBOSH, IOSH, IWFM & CITB training provider, as well as a ProQual-approved NVQ centre.

We are rated 4.9/5 on Trustpilot, and you can read our reviews here. If you would like to speak to us about your training needs, please get in touch using the button below.