Underground service strikes still take far too many days out of UK projects. The task looks simple enough: dig a hole. In practice, the ground is full of live infrastructure, much of it poorly recorded or altered years ago. A permit-to-dig is the site’s control to slow down a high‑consequence task, pull the right people into the conversation, and set clear rules for how the ground will be opened. When it’s treated as a live, supervised process rather than a sheet of paper, the risk drops sharply and productivity actually improves because the team isn’t lurching from one surprise to the next.
TL;DR
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– Agree the dig limits, get up-to-date plans, and scan/mark before any bucket moves.
– Use trial holes with insulated hand tools to confirm, then control plant distances around live services.
– Keep the permit live: re‑brief each shift, refresh markings after weather, and stop if anything changes.
– Nominate one excavation controller and hold photographic evidence of what was found and where.
What sits under our feet: buried services and risk basics
/> Expect electricity, gas, water, drainage, and data in almost every street, yard and verge. Private feeds, temporary builders’ supplies and legacy cables from previous developments often sit outside statutory plans. The harm from contact ranges from nuisance outages and flooding through to fires, explosions and serious injury. The controls are well-known: locate, verify, and only then excavate to a plan that keeps people and plant separated from live services.
A permit-to-dig packages those controls into a single, time‑bound decision. It records what information has been gathered (utility plans, surveys, scans), what was found (trial holes, photographs), and how the dig will proceed (method, plant limits, supervision). It also defines stop conditions: findings don’t match plans, markings get disturbed, a design change arrives, or a different machine or operator turns up. PPE is not the control here; it’s the last layer if something else goes wrong.
From plans to turf: how a permit-to-dig should run on site
/> Good permits start before the bucket. Utility plans are requested and reviewed against the works footprint; if the site is big or complex, a targeted survey using a cable avoidance tool and signal generator is arranged and the detected routes are marked on the ground. Dig limits and exclusion zones are set out with stable markers and paint. The supervisor briefs the excavation team: where services are expected, how they’re marked, which tools are allowed where, and who stops the job if anything doesn’t look right.
Trial holes are then used to prove positions and depths. Hand digging with insulated tools is the norm near suspected services; mechanical plant only comes in when the ground has been proved clear to agreed limits. Vacuum excavation is a good option where the risk is high or access is tight. One person – often the excavation controller – owns the permit on the day, monitors the boundaries, manages plant/pedestrian segregation, and keeps records. Temporary works for trench support and edge protection are set before people enter a void. If rain washes markings off or the dig line moves, the permit is paused, the area is re‑scanned and re‑marked, and the team re‑briefed.
# Permit-to-dig essentials checklist
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A short, practical checklist keeps the permit honest when the pressure is on.
– Utility plans collated, dated, and relevant to the exact dig area.
– Area scanned with a cable avoidance tool and generator; markings transferred clearly to the ground and a sketch.
– Trial holes planned at logical points (changes in route, tie‑ins, crossings) using insulated hand tools.
– Method confirms plant type, slew limits, approach angles, and who banks plant when working near services.
– Exclusion zones, barriers and signage set to keep non‑essential people out and spoil/plant away from edges.
– Stop triggers listed plainly on the permit and understood by every person in the dig team.
# Scenario: drainage tie-in on a live retail park
/> A civils gang is tying new drainage into an existing manhole just off a retail car park. The programme is tight and store deliveries are due at 10:00. Plans show multiple data ducts and a low‑voltage cable crossing the line. The team scans and mark up, then open two trial holes with insulated shovels, finding the cable close to the intended trench edge. Overnight rain smears paint marks and moves a timber peg; the 360 operator lines up to dig and the banksman spots the mismatch between the sketch and the remaining ground marks. Work is paused, the permit is suspended, the area is re‑scanned and re‑marked. By 09:30 the trench is re‑positioned 600 mm away from the cable, a vacuum excavator exposes the crossing, and the tie‑in finishes before deliveries arrive.
Common mistakes
/> Below are frequent ways good intentions unravel around ground openings.
# Trusting utility plans as precise locations
/> Plans tell you what might be there, not exactly where. Always scan and prove with trial holes before bringing in plant.
# Letting paint do all the supervision
/> Ground markings fade, wash off, or get buried under spoil. Keep a sketch on the permit, use durable markers, and brief locations every shift.
# Assuming yesterday’s permit covers today’s change
/> A new operator, a different machine, a shifted trench line or fresh weather means the permit needs re‑issuing or pausing. Treat the document as live, not a one‑off pass.
# Hand digging with the wrong tools
/> Standard shovels and picks can cut services. Use insulated hand tools and expose progressively, watching for warning tape, tiles or bedding changes.
Practical fixes that stand up to pressure
/> Make the excavation controller visible and empowered to stop work. Build hold points into the method: for example, no plant beyond stakes X–Y until trial hole A confirms the duct run. Photograph every exposure with a tape or scale and pin the images to the permit; it speeds decisions when conditions change. Where services are dense, bring in vacuum excavation early rather than as a rescue measure. Keep spoil on the safe side of the trench, away from known or suspected services, and preserve access for emergency isolation if it exists.
# Next 7 days on live digs: make the permit do the work
/> Focus on freshness: refresh the utility search if drawings are old or the dig line has crept, and have your scanning kit calibrated and available, not “due next week”. Tighten the daily startup: five‑minute brief at the hole with the sketch, yesterday’s photos and the stop triggers read out loud. Put a second pair of eyes on plant movements near any live service, with a banksman controlling approach and slew. If rain, frost or night shifts are in play, plan to re‑mark at the start of each shift and suspend if visibility is poor. Finally, give your controller permission to say “not today” when anything feels off; losing an hour often prevents losing a week.
A permit-to-dig is only as good as the behaviours around it. The watch points now are competence drift in scanning and supervision, and pressure to “just get it done” as programmes compress. Two sharp questions for your next briefing: what would make us stop, and who has the authority to do it without a debate?
FAQ
# What should be in a permit-to-dig pack before we break ground?
/> Include current utility plans, results from a recent scan, a clear sketch of expected routes and dig limits, and the method with plant limits and trial hole locations. Add emergency contacts for utility owners, photos as you expose, and the named controller responsible on the day.
# Who leads the excavation when several subcontractors are involved?
/> Nominate one excavation controller agreed by the principal contractor, usually the supervisor of the team doing the digging. They coordinate scanning, marking, briefings and hold points, and they have the authority to stop if conditions or personnel change.
# How often should we re-scan or re-mark the area?
/> Re-scan when the dig line moves, when marks are disturbed by weather or traffic, or at the start of a new shift in busy areas. If you are uncertain about a route, assume it needs fresh verification before plant moves.
# What’s a sensible approach near known live cables or gas?
/> Use insulated hand tools to expose and confirm the line and depth, then set plant approach and slew limits that keep a physical gap. Consider vacuum excavation for the last stretch, use a banksman, and keep exclusion barriers so only essential people are near the workface.
# How do we deal with finding an uncharted service?
/> Stop, make the area safe, and do not cover it back up. Inform the site manager and the utility owner if identifiable, record location and photos on the permit, and adjust the method and temporary works before restarting under a re‑brief.
