Striking a buried service is one of those incidents that stops a project dead and leaves people shaken. A permit-to-dig isn’t a formality; it’s your last gate before putting people, plant and programme at risk. Good sites treat it as a live control across planning, scanning, supervision and close-out, not a sheet clipped to a clipboard.
TL;DR
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– Build the permit around clear scope, current utility records, competent scanning and supervised trial holes.
– Mark services visibly and keep the markings fresh; hand-dig within agreed distances and use insulated tools.
– Brief the team at point of work and manage change: stop if the plan, ground or people change.
– Keep plant and pedestrians apart; use a spotter and enforce exclusion zones.
– Close out properly: as-built photos, updated records and a tidy hole.
The service-strike controls playbook
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Define the dig and its boundaries
Start by being precise: where, how deep, how wide and what method. Split the area into zones where plant is allowed, where hand-dig only applies, and where no break is permitted without further proving. Consider ground conditions, temporary works needs and interfaces with traffic management and other trades. Record the planned sequence and hold points inside the permit so everyone understands when work must pause for checks.
# Map and validate the records
/> Request statutory utility drawings early and treat them as indicative, not definitive. Overlay them on your site plan and add any known private services from the client or building management. Walk the area to find street furniture, meter positions and tell-tale signs such as repaired trenches or recent reinstatement. If records are unclear, assume more services than shown and tighten your plan, not the other way round.
# Locate and prove with competent scanning and trial holes
/> Use a calibrated locator with a competent operator, working through passive and active modes and induction where possible. Mark detected services on the ground with clear colour coding and arrows for direction. Always prove positions with hand-excavated trial holes before bringing in plant, and widen the proving area where accuracy matters, such as near a cable crossing. Keep the operator with the crew or ensure a clear handover of findings, photos and mark-up.
# Lock in the permit and any isolations
/> Authorise the permit on the day of the dig, after the latest scan and markings are in place. Confirm any agreed isolations or service shutdowns in writing and physically verify them at valves, panels or cabinets, not just on email. State the last responsible person to approve changes and the triggers for stopping work. Ensure people signing the permit have actually seen the area, the markings and the workforce they’re approving.
# Control the live dig with supervision and separation
/> Brief at point of work with the crew around the markings, not in the canteen. Hand-dig near known or suspected services using insulated tools and never use mechanical breakers until the service is fully exposed and supported. Maintain exclusion zones around the plant and set a clear role for the spotter or banksman, who should focus solely on the dig face and markings. Keep spoil placement controlled, protect exposures against collapse, and manage water ingress so services remain visible and supported.
# Manage change, capture findings and close out
/> Stop when anything deviates: ground differs, a service isn’t where expected, the operator changes, light fails or the method shifts. Update the permit, brief again and re-commence only when risks are controlled. Photograph exposed services with measurements and fixed references, then backfill steadily with suitable material to avoid damage. At the end, update your records and close the permit with signatures and attachments so future teams aren’t starting from scratch.
A near-miss on a housing civils phase
/> A subcontract gang arrived to install a drainage spur across a new estate road before the tarmac crew. The supervisor had a permit from the previous week, and the locator had marked a gas main running parallel to the kerb. Overnight, the kerb line was adjusted by the civils team to improve levels, shifting the trench position by half a metre. The gang started with a mini excavator, following the spray marks, but the spotter noticed the new kerb alignment did not match the permit sketch. Work was halted and a quick rescan found a second service, a private water line, now directly in the dig path. Trial holes confirmed both services at shallow depth after recent raising of cover levels. The team re-planned the trench, hand-dug through the crossing and kept plant back until both services were exposed and supported.
Common mistakes
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Assuming last week’s scan still stands
Ground changes fast on active sites. If the area shifts, the scan and permit are out of date.
# Treating the locator as magic and skipping trial holes
/> Locators aid decisions; they don’t replace proving. Trial holes make the guesswork visible.
# Signing the permit from the office
/> Authorising without seeing the ground and markings creates false assurance. Permits should be felt under your boots, not just seen on paper.
# Letting the plant set the pace
/> Programme pressure nudges crews into mechanical digging too close to services. Keep hold points and stop-work triggers non-negotiable.
Checklist: essentials before you break ground
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– Up-to-date utility records obtained, overlaid and walked out with visible features noted.
– Calibrated locator used by a competent person; markings photographed and referenced.
– Trial holes planned and executed to prove service positions, depth and direction.
– Permit authorisation completed at point of work, with isolations verified physically.
– Exclusion zones set, banksman/spotter briefed, and traffic management aligned to the dig.
– Method statement covers hand-dig limits, insulated tools, support to exposed services and temporary works.
– Stop-work triggers listed: unexpected service, loss of markings, poor light, method change, or personnel change.
Bottom line: keep the permit live
/> The best permits are living controls that move with the job, not signatures trapped in yesterday’s plan. If the site changes, the permit changes, and digging pauses until everyone can see the safer route forward.
# This week on site: close the gaps before you dig
/> Walk your upcoming dig areas with the locator and supervisor together, not separately. Brief crews at the edge of the trench with flags, paint and photos in hand so the plan is visible. Mark out hand-dig buffers clearly and refresh them daily as the excavation advances. Stage your plant so the first bite is always away from suspected lines and your spotter has a clean view. Escalate any uncertainty immediately and be comfortable resetting the permit rather than “making do”.
Regulators and clients are watching how seriously sites treat buried services, especially where programmes tighten and night shifts creep in. Ask yourself: Are our scans current, are our stop-work triggers understood, and would a new crew read our ground the same way tomorrow?
FAQ
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When do I actually need a permit-to-dig?
Use a permit whenever there’s a foreseeable chance of encountering buried services or when working within known service corridors. It’s also good practice around building edges, near street furniture, or where drawings are old or patchy. Even shallow excavations can hit ducts or cables on refurbished or raised sites.
# Who should sign off the permit?
/> Authorisation should come from someone competent who has physically inspected the area and understands the sequence, not just a manager remote from site. On many projects that’s the principal contractor’s supervisor or site manager, with the subcontractor’s supervisor also signing to accept the controls. Keep the signatories available to respond if conditions change.
# How often should services be re-scanned?
/> Re-scan whenever the dig footprint moves, levels change, ground is disturbed by others, or the markings become unclear. Daily scanning before recommencing is good practice in busy areas or where services are dense. Treat any delay, shift change or method change as a cue to confirm nothing has altered.
# What if we expose an unexpected service?
/> Stop, make the area safe and protect the exposure from damage or collapse. Inform the site lead and principal contractor, and contact the utility owner where relevant before proceeding. Update the permit, brief the team on the new control measures and only restart once the risk is under control.
# How do we manage plant and people safely around a live dig?
/> Plan fixed exclusion zones with barriers and clear routes, and position the banksman where they can see the bucket, markings and crew. Keep pedestrians out of the swing radius and set spoil heaps to avoid roll-back or obscuring services. Coordinate with traffic management so deliveries don’t force people into the dig area, and keep housekeeping tight to stop slips and trips near exposed services.
