Breaking ground without a disciplined permit process is still one of the quickest ways to injure people, shut down a site and sink a programme. Striking live electricity, gas, water, comms or district heating lines is rarely “just” a delay; it often triggers evacuations, utility call-outs, damage claims, and stressed workers taking bigger risks to catch up. A permit to dig is not an A4 sheet to satisfy the folder—it’s a live control linking desk studies, survey, marking out, method, supervision and stop-work triggers. Done well, it prevents guesswork, sets boundaries for plant, and makes sure every shovel of spoil is taken with eyes open.
TL;DR
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– Get reliable service information, then prove it in the ground before any machine touches it.
– Issue permits with clear boundaries, conditions, validity and stop-work triggers—briefed at the hole, not in the office.
– Hand-dig or vacuum expose, support and mark services; only then consider controlled mechanical excavation.
– Keep plant and people separated, use a dedicated banksman and stop on any mismatch between plans and reality.
– Reissue the permit for any change: new plant, shift, weather, route or finding.
Controls playbook for service-safe digging
# Stage 1: Desk study and service enquiries
/> Start with up-to-date plans from asset owners and recent as-builts, not the dog-eared drawings found in a site hut. Capture known temporary supplies, private cables and recent diversions. Map the work area against these records and agree the approach with the supervisor, permit authoriser and, where relevant, the temporary works coordinator. Decide early which areas are “no mechanical dig” and where vacuum excavation is justified. Line up isolations or stand-by arrangements with utilities if practicable. Nominate who is competent to issue, brief and close permits.
# Stage 2: Marking out and surveys on the ground
/> Complete a competent CAT and Genny sweep and mark services with a consistent colour code, arrows and offsets to fixed features. Where the route is unclear or congested, consider a utility mapping survey by a specialist; treat outputs as intelligence, not exact truth. Record photos of markings and keep them with the permit pack. Establish tolerances and protective stand-offs; for example, a marked corridor either side of likely services where only hand or vacuum methods are allowed. Brief everyone on the meaning of the marks—no guessing what “X” or a faded line might mean.
# Stage 3: Permit issue and briefing at the hole
/> Issue the permit as the final gateway before breaking ground, at the exact location, tools and plant present. State the boundaries, depth limits, service corridors, allowed methods, supervision arrangements, emergency plan, and how long the permit is valid. List incompatible activities nearby (e.g. hot works, piling, heavy deliveries) and how interference will be managed. Keep a copy with the gang; keep the master with the supervisor. Make sign-in more than a scribble—ask simple control-check questions to prove understanding.
# Stage 4: Breaking ground and proving services
/> Use hand tools or vacuum excavation to expose, locate and positively identify services along the planned run. Clean, tag and support exposed services; never leave them hanging in a trench wall. Confirm actual depths and alignments and compare them with plans; correct the mark-up and permit if there is any mismatch. Maintain trench edge protection and access arrangements as you go; a tidy hole is easier to supervise. Photograph each exposure and store these with the permit so the next shift knows what’s truly there.
# Stage 5: Controlled machine digging and change control
/> Only bring in plant once services are located, protected and the permit explicitly allows mechanical excavation. Use a dedicated banksman focused solely on the excavation—not also controlling deliveries or answering the phone. Keep plant slewing and reach within agreed limits, and maintain exclusion zones so no one enters the arc. Stop immediately if the ground changes, markings stop making sense, or you encounter unmarked obstructions. Rebrief and reissue the permit for any change in scope, method, operator, shift or weather.
# First-week priorities on buried services
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– Confirm who is competent to authorise permits, and ringfence their time so they can attend at the excavation, not sign from a desk.
– Walk the exact dig line with the CAT and Genny, then remark up with offsets and photo evidence before the team mobilises.
– Tag any exposed services with type, voltage/medium (if known) and direction of flow; protect with foam, boards or matting.
– Photograph every trial hole with a scale and fixed reference; file it where the night shift can actually find it.
– Stage deliveries and plant routes away from service corridors to avoid tracking over unknowns or newly exposed lines.
– Escalate immediately to the manager if any planned hand-dig area starts to look like a mechanical dig out of convenience.
Scenario: drainage connection on a live housing street
/> A groundworks gang is tying a new plot drain into an existing manhole on a phased housing site. The asset plans show an LV cable running loosely parallel to the kerb, and the supervisor’s CAT sweep is inconclusive because of interference from a nearby substation. The permit is issued for hand-dig only with vacuum assistance. On the first trial hole, the team finds a shallow telecoms duct 400 mm off the expected line and a second, private cable that wasn’t on any plan. They tag and support both, revise the markings, and the permit is reissued with a tighter exclusion corridor. Only after exposing the section fully is a 3-tonne excavator allowed in, with a banksman and a stop line painted at the approach. The connection is made without incident, and the photos go into the plot file so the utilities aren’t “lost” on the next phase.
Common mistakes when issuing and using permits to dig
# Treating old utility plans as precise locations
/> Plans are often indicative; relying on them as exact positions is how strikes happen. Always prove services in the ground.
# Allowing permits to roll across shifts
/> A permit that quietly “continues” invites drift. Rebrief each shift and reissue if conditions, people or methods change.
# Marking paint that no one can interpret
/> Random colours and cryptic symbols make sense to the marker and nobody else. Use consistent codes, arrows and offsets to fixed features.
# Leaving exposed services unsupported
/> Exposed lines sag and get nicked by buckets. Support, protect and clearly tag them before work continues.
Bottom line on permits for groundworks near services
/> Permits to dig only work if they are treated as a real control loop: enquiry, survey, mark-up, brief, prove, protect, and reassess at the first sign of doubt. If any link is weak, you’re back to gambling with live services. Watch for the quiet drift—expired permits, missing photos, plant creeping closer—as programmes tighten and shifts stack up. Two questions for the next briefing: what would make us stop immediately, and who has the authority on the ground to enforce it?
FAQ
# When do you actually need a permit to dig?
/> Use a permit whenever breaking ground where buried services may exist or where previous works might have installed private lines. That includes trial holes, fence posts, small footings and kerb slots, not just big trenches. Treat it as the gateway that links your surveys and method to a live, controlled task.
# Who should issue and sign the permit?
/> A competent person who understands buried service risks, the method statement, and the survey results should authorise it. They must attend the work area to brief the team and confirm controls are physically in place. The supervisor and lead operative should sign on to confirm understanding and acceptance of the controls.
# Is a CAT and Genny scan enough?
/> A scan is a starting point, not a guarantee. Ground conditions, congestion and interference can mask lines, and non-conductive services may not be detected. Combine scanning with plans, vacuum or hand exposure, and treat unknowns with conservative methods until proven.
# How do you manage subcontractors joining mid-task?
/> Pause and integrate them properly: brief the permit conditions at the hole, show photos of proven services, and add them to the sign-on. Confirm their kit and methods match the permit; if not, revise before continuing. Never assume a new crew “knows the drill” without a targeted induction to the live controls.
# What should trigger stopping the dig and reassessment?
/> Stop if you find uncharted services, depths or routes don’t match markings, the ground changes, or protection cannot be maintained. Also pause if plant, personnel or weather changes undermine the agreed method. Rebrief, update the permit, and only restart when controls match the new reality.
