Programme pressure doesn’t just squeeze productivity — it squeezes decision-making. When the gang is stood around waiting for a machine, and the foreman is getting chased for dates, the temptation is to “get a bucket in the ground” and sort the paperwork after. That’s exactly when buried services get hit.
A permit to dig is meant to slow the job down just enough to stop a service strike. Done properly, it isn’t bureaucracy; it’s a short, controlled pause that forces everyone to agree what’s in the ground, what’s been proved, and how the excavation will be carried out safely. The keyword is prove — not assume.
The supervisor view: what changes when the programme tightens
Supervisors and site managers rarely set out to take shortcuts. Under pressure, the shortcuts happen by drift: a permit gets treated as a signature exercise, the locating work gets rushed, and the dig method quietly changes once the excavator arrives. Service strikes often sit at the intersection of poor information, weak control of changes, and a rushed start.
The highest-risk moments are predictable:
– first break of ground on a new phase
– late changes to excavation lines for drainage, ducting or foundations
– “just a small scrape” to make levels work
– multiple subcontractors working in the same corridor (groundworks, utilities, landscapers)
– shift handovers where assumptions get passed on as facts
A good permit to dig process makes those moments visible and managed, not improvised.
How a service strike happens in real life (and why the permit matters)
On a city-centre refurbishment, a subcontract groundworks gang is told to trench for a new incoming water supply behind the hoarding. The streetworks permit is in place, but inside the site the team is trying to catch up after a delayed delivery and lost half a day to traffic management changes. The supervisor pulls old utility drawings from the folder and marks the trench line with paint. A locator comes out, gets a weak signal near the hoarding line, and says it might be “something old” but the excavator is already on site. The banksman keeps the bucket shallow, but the trench edge crumbles and the operator takes one more pass to tidy. There’s a bang, a flash, and the job stops: a live low-voltage cable has been clipped, which wasn’t shown on the drawings and was masked by rebar in the slab edge. The incident doesn’t just create danger — it triggers a stand-down, emergency call-outs, and a programme hit that dwarfs the “time saved” skipping proper proving.
This is where the permit to dig earns its keep: it creates a controlled decision point before the bucket moves, and it forces agreement on locating, trial holes, safe digging methods, and what happens if anything doesn’t match the plan.
Controls that keep digging safe without killing progress
A permit to dig should translate directly into site actions. If the permit reads well but the ground doesn’t, the ground wins. The point is not to “tick” services avoidance — it’s to reduce uncertainty in a messy environment.
# Make information usable: drawings, surveys and assumptions
Utility plans are rarely perfect. They can be out of date, clipped, drawn to low accuracy, or miss private services. Treat them as a starting point, not permission to excavate.
Good practice looks like:
– correct, current drawings for the specific area and phase, not last month’s pack
– clear marking of the proposed excavation limits (with dimensions)
– a short statement of what is assumed (e.g., depth unknown, and any service could be present)
If the permit doesn’t say what is known and what is unknown, it won’t drive safe behaviour.
# Proving, not guessing: locating and trial holes
Locating tools help, but they don’t remove the need to prove. A permit to dig should set out how services will be confirmed in the ground before mechanical excavation gets near them.
Practical points that reduce risk:
– competent operatives using calibrated locating equipment
– scanning both along and across the route, not just on the line
– trial holes at conflict points (changes of direction, near chambers, at tie-ins)
– hand-digging or vacuum excavation where uncertainty stays high
If the locating results are weak, inconsistent, or don’t match the drawings, that’s a stop-and-replan moment — not a “careful scrape”.
# Control the excavation method: plant, hand tools and exclusion
Most service strikes happen with an excavator bucket, not a shovel. The permit should specify where mechanical digging is allowed, where it’s restricted, and what the safe approach is when nearing identified services.
Minimum site realism:
– define an exclusion zone around the excavation and service corridor
– use a banksman with authority to stop the machine (not just “watching”)
– set expectations on bucket size, bite depth and approach angle
– keep spoil and materials back from trench edges to avoid collapse and re-digging
Remember: even if you don’t hit the service directly, undermining or moving it can create delayed failures.
# Manage changes: when the job deviates from the permit
Programme pressure often shows up as “minor” changes: shifting a trench to miss a manhole, deepening to find a fall, widening for working space. Those changes invalidate the assumptions on the permit.
Strong sites do two simple things:
– they treat changes as a trigger for re-authorisation (even if quick)
– they make the supervisor physically re-walk the line with the gang before restarting
If the dig changes, the permit changes, and the locating/proving may need doing again — that’s not paperwork; it’s control.
Permit-to-dig walkround prompts (5–7 items)
Use this quick list before the first cut, and again after any change or handover:
– Confirm the excavation boundary on the ground matches the permit sketch and the latest drawing pack.
– Verify services have been located and marked consistently, including across the route and at tie-in points.
– Ensure trial holes/proving locations are completed or clearly planned before mechanical excavation approaches.
– Brief the operator and banksman on the permitted digging method, approach, and stop points.
– Check protection for exposed services (support, barrier, and no loading from spoil or plant).
– Set an escalation trigger: any uncharted service, weak signal, or mismatch stops the dig until re-authorised.
Common mistakes
# Treating the permit as a signature, not a control
/> The form gets signed in the office while the gang is already setting out. That reverses the logic: the permit should lead the work, not chase it.
# Relying on one source of truth
/> A single utility plan or a quick scan is taken as “proved”. When information conflicts, the safest assumption is that more is in the ground than you think.
# Letting the excavation “creep”
/> The trench line moves a few hundred millimetres, or the depth increases to make falls work. Small changes can take you into a new services corridor.
# Weak stop authority at the machine
/> Banksmen sometimes feel they’re there to guide, not to stop. If nobody can confidently stop the bucket, the permit-to-dig system is just words.
Keeping momentum without shortcuts: what supervisors can do today
The best supervisors don’t fight the programme by saying “no” to everything; they protect the programme by stopping the incidents that cause stand-downs, rework and emergency call-outs. A permit to dig helps when it’s used as a coordination tool: it aligns the dig, the plant, the proving, and the interfaces.
Two habits make a measurable difference on real sites:
– Put the permit briefing at the excavation edge, not in the cabin or the site office. People remember what they see and touch on the ground.
– Maintain a simple “services corridor” mindset: keep plant, materials, and last-minute storage away from the route, so you’re not forced into risky re-digs.
Also watch the interface risks that often sit outside “digging”: deliveries crossing the trench line, traffic management shifting barriers, temporary works affecting access, and housekeeping failures that hide markings under mud and spoil.
Seven days to fewer service strikes under pressure
# A one-week services strike squeeze-out plan
/>
1) Map out the next week’s excavations on a single board plan so clashes and tight turnarounds are visible early.
2) Assign one named competent person per shift to own locating/proving quality and stop the dig if signals don’t stack up.
3) Re-sequence plant so vacuum excavation or hand-proving happens ahead of the excavator arriving, not after it’s waiting.
4) Introduce a short handover script at the trench edge covering “what’s been proved, what’s still unknown, and where the stop points are”.
5) Ring-fence the services corridor with barriers and storage rules so spoil piles and materials don’t force unsafe changes mid-task.
Service strikes are rarely “bad luck”; they’re usually a visible chain of compromises made under time pressure. If the permit to dig doesn’t change what happens at the excavation edge, it’s not doing its job — and the next surprise in the ground will arrive exactly when you can least afford it.
