Service strikes remain one of the quickest ways to turn a straightforward dig into an emergency, a claims battle, and days lost on programme. A robust permit-to-dig is the control that stops ground being broken until the risk is understood, the method is engineered, and the team is briefed. It’s not a form to get a spade in; it’s a live decision point that coordinates drawings, surveys, mark-out, supervision, temporary works and plant movements to keep everyone away from electricity, gas, fibre and water.
TL;DR
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– Freeze the dig area, gather current utility plans and reconcile them to site conditions before any mark-out or breaking ground.
– Verify with competent locating and trial holes; assume plans are incomplete until you’ve proved they match the ground.
– Engineer the method: hand-dig, vacuum excavation, exclusion zones, plant-pedestrian segregation and trench support where required.
– Issue a short-life permit, brief it, and stop the job if conditions change or marks are unclear; revalidate daily.
A staged permit-to-dig playbook for utility-safe excavation
# Stage 1: Define the dig and freeze the zone
/> Pin down what is being penetrated (trial hole, post hole, trench, kerb line), the exact footprint and depth range, and when it will be done. Fix an exclusion around the area to prevent early breaking ground, and identify interfaces with traffic routes, deliveries and other trades.
# Stage 2: Gather and reconcile service intelligence
/> Source the latest statutory utility plans and any client as-builts or previous surveys; note their issue dates and confidence levels. Overlay them to your setting-out, walk the area with a supervisor, and flag gaps or conflicts for escalation before you touch a locator.
# Stage 3: Mark out and verify with locators
/> Use a competent person with a cable avoidance tool and signal generator to scan the area, in all modes, before marking lines and zones on the ground. Treat the mark-out as provisional until verified by trial holes or vacuum excavation at key crossings and depths.
# Stage 4: Engineer the method and protections
/> Select low-risk techniques near services: hand-dig, insulated tools and vacuum excavation where feasible; plan saw-cut depth stops and avoid pecking with breakers over suspected services. Build in plant-pedestrian segregation, spoil placement, edge protection and temporary works for trench support and crossings.
# Stage 5: Permit issue, briefing and hold points
/> The permit sets the boundaries, identified services, method, PPE, isolations (if any), competent operator names, and expiry. Brief the team at the workface with the marked-up plans, agree hold points (e.g. stop 300 mm above a suspected line), and record who attended.
# Stage 6: Control the live dig and change management
/> Keep the permit visible at the workface, and have the supervisor present for the first penetration and each hold point. If marks are unclear, depths vary, unexpected ducts appear or rain floods the area, stop, make safe, and revalidate or reissue the permit before continuing.
# Stage 7: Close-out, as-builts and reinstatement
/> On completion, capture as-built positions and depths of any exposed services and submit to the project records. Remove misleading marks, reinstate safely, and log lessons for the next permit so intelligence improves across the job.
Site scenario: misplaced confidence on a civils tie-in
/> A housing site is forming a new entrance, cutting into an existing footway to set kerbs and install a drainage connection. The gang has utility plans from three months ago and a mark-out done the previous week. A mini-excavator starts tracking in to lift the first bucket when the operator sees a shallow orange duct not on the drawing. Work stops; the supervisor suspends the permit, cordons the area and calls for vacuum excavation. The duct proves to be a recent fibre diversion completed by others without updated records. The team adjusts the alignment by 250 mm, hand-digs the crossing and reinstates with temporary works in place for the open trench. The half-day pause avoids a strike, a street outage and a bruising conversation with the client.
Common mistakes that sink permits to dig
# Treating utility plans as the ground truth
/> Plans are often indicative or out of date. Without competent locating and trial holes, you’re guessing.
# Issuing long-life permits that drift
/> Permits left open for weeks become wallpaper. Short validity and daily supervisor revalidation keep control live.
# Relying on PPE and luck near live services
/> Insulated gloves and boots won’t save a crew from poor method selection. Engineer the risk out and keep metal away from suspected lines.
# Letting plant movements dilute controls
/> Changing bucket types, swapping operators or tweaking alignments on the fly breaks the method. Any change needs a stop and re-brief.
Seven-day push: make permits to dig watertight
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– Audit one live permit area each day: can operatives point to marks, hold points and the supervisor in charge?
– Replace faded or washed-out mark-out and revalidate with a fresh locator sweep after heavy rain or overnight works.
– Bring vacuum excavation to the programme for upcoming crossings; don’t leave it as a last-minute hire.
– Walk plant routes and spoil zones with traffic management in mind; adjust barriers to maintain segregation and visibility.
– Sit down with the utility surveyor and the setting-out engineer to agree confidence levels and tie points before next week’s digs.
– Capture as-builts with photos and chainage notes at exposure points; file them where the next permit writer will actually find them.
Bottom line on service strike prevention
/> A permit-to-dig only works if it slows you down at the right moments: before the first bite of ground, at hold points, and when something doesn’t look right. Keep the document short, the mark-out fresh, the method conservative near services, and the supervision visible; the rest is discipline.
FAQ
# When should a permit to dig be used on site?
/> Use a permit whenever you intend to break ground, even for small hand-dug holes, because services can be shallow and unrecorded. It’s especially important in pavements, verges, near existing buildings, and on brownfield or refurbished sites where past works are unknown.
# Who is competent to issue and brief a permit?
/> Typically a site manager or supervisor with practical excavation experience, understanding of service risks, and familiarity with locating methods should authorise and brief. They need enough authority to stop the job, organise further surveys, and coordinate with temporary works and traffic management.
# How long should a permit be valid?
/> Short periods are safer—often a shift or a day—because weather, site traffic and mark-out can change quickly. If work pauses, the area floods, or plant or personnel change, suspend and revalidate or issue a new permit rather than carrying on under an assumption.
# What if we find an unexpected service?
/> Stop work immediately, make the area safe, and widen the exclusion zone to keep plant and people clear. Bring in a competent locator or vacuum excavation to expose and identify the service, update the plans and the permit, and only restart after a fresh briefing.
# Is hand-digging always required near services?
/> Close to suspected lines, controlled hand-digging is a sensible default, with insulated tools and careful exposure. Vacuum excavation is a good option where ground conditions and access allow; choose the method that minimises strike risk and still fits your temporary works and traffic management plan.
