Cable strikes remain one of the most stubborn, preventable causes of life-changing injury, project delays and public disruption on UK sites. Too often, the permit-to-dig becomes a laminated comfort blanket rather than a live control. The fix isn’t a thicker form; it’s a tighter workflow, stronger supervision, and conditions that bite on the day of the dig, not just at the pre-start meeting.
TL;DR
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– Stop treating the permit as paperwork; tie it to a real mark-out, competent CAT & Genny, and trial holes before plant moves.
– Build in hard stop triggers: unclear markings, rain washing off paint, change of method, or fresh operatives on shift.
– Keep supervision with the hole, not the office: first spade watched, plant exclusion enforced, and daily re-validation of the permit.
– Use vacuum excavation or hand-dig near suspected services; never rely on old drawings without proving.
– Close the loop: update service trackers, photos, and lessons learned so the next dig starts smarter.
A permit-to-dig that actually controls risk
# Stage 1 – Gather service intelligence early
/> Start with all utility plans, but don’t kid yourself they’re accurate. Commission a competent utility survey where risk or complexity warrants it, informing the design and temporary works. Log clashes, unknowns and likely corridors; this is the baseline for every later control, not a file to archive.
# Stage 2 – Plan the dig and temporary works around known and suspected services
/> Shape the method to avoid or span services where possible. Align excavation support, spoil placement and plant routes so no load sits over potential service lines. If a reroute isn’t viable, plan for lower-risk techniques, such as vacuum excavation or careful hand-dig, for the first proof-holes.
# Stage 3 – Permit set-up: mark-out, CAT & Genny, and comms
/> Only issue a permit after a competent CAT & Genny sweep and visible mark-out on the ground, with photos. Brief the crew at the hole, not the canteen, using the actual markings and the permit limits; agree stop points and proving holes. Include who is competent to scan, when rescans are required, and what happens if weather or site traffic removes markings.
# Stage 4 – Supervise the first spade: day-one controls that stick
/> The first exposure is where strikes happen. Supervisor present, insulated hand tools for trial holes, and plant held back until the service corridor is proved. Enforce exclusion zones, banksman positioning, and a pace that allows decisions, not guesses.
# Stage 5 – Manage change, pauses and handovers
/> Any change to depth, alignment, plant, ground conditions, or people means the permit is paused and re-validated. At shift change, walk the line again: re-scan, refresh the mark-up, and re-brief the new team. Rain, poor light, mud or rebar interference are all signals to slow down and reassess.
# Stage 6 – Close-out and feed back
/> When the dig is complete or halted, record what you actually found: photos with tape measures, updated service trackers, and a quick note of lessons for the next location. Capture near-misses as data, not blame. Feed it into future planning so the next permit starts closer to the truth.
Scenario: drainage connection on a live retail park
/> A civils gang is booked for a nightshift to tie a new gully into an existing line across a service-rich car park. Drawings are vague, with several historic refurbishments. The supervisor arranges a late-afternoon CAT & Genny and marks a suspected LV run clipping the excavation route. On arrival at 19:30 it’s raining; the paint is already fading. The plant operator wants to “get a bite in” before the shop closes at 20:00. The supervisor holds the dig, re-scans, and moves the trial hole 600 mm, uncovering an unrecorded cable. Vacuum excavation is brought in for the next night, the alignment is nudged, and the tie-in completes without incident. The updated service tracker and photos mean the next three gullies are replanned, avoiding the cable completely.
Common permit-to-dig mistakes
# Issuing permits from the office
/> Permits signed off without a site mark-out and in-person briefing are guesswork. Control lives where the shovel hits the ground.
# Treating drawings as facts
/> As-builts and utility plans are often outdated. Use them to guide proving, not to replace it.
# No stop-work triggers
/> If the permit doesn’t define when to pause and re-validate, operatives will push through uncertainty. Build in clear triggers tied to conditions on site.
# Letting the permit expire quietly
/> Permits that roll across shifts without re-briefs are theatre. Re-validate after weather, breaks, or crew changes, and document it.
Next 7 shifts: make the permit bite
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– Walk every planned excavation line with a CAT & Genny and take timestamped photos of the mark-out.
– Re-write one permit template to include specific stop triggers and re-validation steps suited to your site.
– Arrange a short on-hole briefing for supervisors on insulated hand tools, proving holes, and vacuum excavation options.
– Set up a simple service discovery log with photos and sketch overlays, and share it in the morning coordination meeting.
– Nominate one competent person per shift to own the re-scan before digging resumes after breaks or weather.
– Move barriers and banksman positions so plant cannot slew across suspected service corridors.
– Agree a rule with the QS/PM that programme pressure is not an excuse to bypass proving holes near services.
Bottom line
/> A permit-to-dig that works is a control loop, not a certificate. Mark-out, prove, supervise the first spade, and pause when anything shifts; if those four behaviours are visible on your site, cable strikes become rare events instead of regular scares.
FAQ
# When is a permit-to-dig needed?
/> Use a permit whenever breaking ground, coring, driving pins, or fixing into slabs and walls where services may be present. It’s a simple way to force planning, briefing and supervision before the risk turns real.
# Who should carry out the CAT & Genny and mark-out?
/> A trained, competent person who knows the equipment’s limits and the site context should complete the sweep. Record findings clearly on the ground and with photos, and don’t rely on one pass if conditions change.
# How do we manage permits across multiple subcontractors and shifts?
/> Keep the permit at the workface and re-brief each incoming crew with the live mark-out. Use a simple handover note with photos and stop triggers so no one assumes yesterday’s conditions still apply.
# What if we uncover a service that wasn’t on the plans?
/> Stop, make safe, and widen the exclusion zone; then inform the site lead and update the permit and service records. Plan the next steps, which may mean rerouting, using vacuum excavation, or rescheduling until the service owner is consulted.
# Are insulated tools and PPE enough protection near services?
/> Insulated tools and appropriate PPE are last-line measures, not primary controls. Proving holes, safe plant positioning, and a live permit with clear stop points are what keep people out of the strike zone.
