Last Updated: November 5, 2026
Quick Summary
To follow HSG47 safely, work through its three stages in order: plan the work and gather service plans, locate and mark buried services with a CAT and Genny, then dig safely using hand tools and proximity zones near marked services. Each stage depends on the one before it, so never skip one.
The logic is simple. You cannot locate what you have not planned for, and you cannot dig safely around services you have not found.
The three stages break down like this:
Skip a stage and the whole system fails. Service strikes commonly trace back to a missing plan, an unmarked route, or a digger operator working outside the agreed zone.
The HSE publishes the full guidance in HSG47 Avoiding danger from underground services, and it is worth reading alongside this article. For a step-by-step walkthrough of putting the process on your own site, see our step-by-step HSG47 implementation guide.
HSG47 breaks down into three stages, each dependent on the one before it.
| Stage | What to do |
|---|---|
| Plan | Gather service plans, survey the site, write risk assessment and method statement |
| Locate and mark | Use cable and pipe locating devices, then mark routes on the ground |
| Safe digging | Hand-dig near services, use proximity zones, stop work when uncertain |
Plans come first, before anyone lifts a spade. Request service drawings from every utility owner in the area: electricity, gas, water, telecoms and drainage.
Treat the plans as a guide, not a map. Utility records are often incomplete, out of date, or drawn to a scale that hides small offsets.
Before excavation, we check three things:
Where records are missing or unclear, plan for the worst case.
A cable avoidance tool (CAT) and signal generator (Genny) are the standard locating kit on site. The CAT detects electromagnetic signals from buried metal services.
Mark every detected route on the ground
If a trial hole reveals a service where the plans said there was none, stop and re-plan.
The risk assessment and method statement are where you follow HSG47 and turn it into your site’s own document. The risk assessment identifies the hazards: buried cables, gas pipes, water mains, and the chance of striking them.
A workable assessment covers:
Keep it specific to the job. Our HSG47 and GS6 compliance guide covers how the two sets of guidance fit together in a single assessment.
Safe digging means matching the tool to the distance from the service. Far from any marked route, a machine may be appropriate.
Set a proximity zone around every marked service and brief the machine operator on it.
Watch out: a common mistake is letting a machine operator work to a mark they cannot see.
Stop-work triggers should be written down and understood by everyone:
Anyone can call stop. That authority needs to be stated in the briefing, not assumed.
A strike is an emergency, and the response depends on what was hit. The general sequence is the same, but the service-specific actions are where mistakes get made.
Electricity cable. Keep everyone clear and do not touch the cable or anything in contact with it, including tools, water or the excavator.
Water main. Move people and plant away from the flow, because a pressurised main can undermine excavation sides and cause collapse.
Telecoms and fibre. Treat the duct as live and do not handle damaged cables. Call the network owner.
A strike is the obvious trigger, but the earlier warning signs matter more. Stop excavation and escalate to the supervisor when:
Anyone can call stop. That authority needs to be stated in the briefing, not assumed. Escalation should name who is called, in what order, and where the contact numbers are kept, a plan that lives only in someone’s head is not a plan.
Work should not restart until the utility owner has confirmed the service is safe, the area has been re-assessed, and the method statement has been updated to reflect what was actually found. A near miss deserves the same review as a strike: was the service on the plans, was it marked, and was the digging method right?
Our guide on keeping groundworkers safe around underground cables walks through the practical steps for cable strikes in more detail.
Training is what turns a written procedure into behaviour on site. HSG47 expects everyone involved in excavation to be competent for their role: the person locating services, the operator, the supervisor and the labourer with the shovel.
Our GS6 and HSG47 training is designed to be practical rather than a box-ticking exercise, and the course content covers locating, marking and setting proximity zones as well as stop-work decisions.
You can see our electrical training courses and check upcoming course dates to plan your team’s sessions.
HSG47 is built on three stages: plan the work properly, locate and identify buried services on site, and dig safely with the right tools and supervision. Planning means getting utility plans and assessing risk before anyone breaks ground. Locating means using cable avoidance tools and signal generators, then marking out. Safe digging means hand tools near services, proximity zones and a permit to dig system.
HSG47 does not set a single fixed distance, but the accepted approach is to stop mechanical excavation well before the service and finish with hand tools. Utility owners’ specified hand-dig zones vary by asset, so confirm the requirement for each service with its owner. Treat any service within your excavation footprint as live until the utility owner confirms otherwise, and mark the proximity zone clearly on the ground.
Stop work immediately, keep everyone clear and do not touch or move the service. Treat it as live. Contact the utility owner or your supervisor, record the location and depth, and do not resume excavation until the service has been identified and the safe system of work updated. If there is any sign of damage, gas smell or exposed conductors, follow emergency procedures and call the relevant network operator.
The duty holder, usually the client and principal contractor, must ensure the work is planned and supervised safely. Site supervisors and competent operators carry day-to-day responsibility for following the safe system of work, using locating equipment correctly and stopping work when conditions change. Everyone on site, including subcontractors, has a duty to report hazards. Training records and permits to dig should show who is competent for each task.
Underground services do not forgive guesswork. If your team needs to follow HSG47 with confidence, SJB Electrical Training delivers hands-on HSG47 and GS6 courses built for groundworks crews, with practical locating exercises and clear stop-work procedures. Get started with SJB Electrical Training and give your teams the competence to plan, locate and dig safely around buried services.
