An unexpected buried service in an excavation: what to do

When a dig exposes a cable, pipe or duct that is not on the plans, stop, keep people clear, and treat it as live and dangerous until the owner proves otherwise. Get competent advice, involve the utility, and revise the method before continuing. Striking an unknown service can be fatal.

What has happened

Groundworks reveal a service absent from the drawings, or a service is found in a different position or depth than expected, or one is struck. Underground cables and pipes cause serious and fatal injuries every year. HSE's HSG47, Avoiding danger from underground services, sets out the plan-locate-dig-safely approach and the principle that any unidentified service should be treated as live and dangerous until confirmed safe by the owner.

Immediate actions

Stop work in the affected area and keep people clear. Do not disturb, lever, move or work around the service. If a service has been struck, treat it as an emergency: for electricity, keep everyone well clear, do not touch the cable or a person in contact with it, and call the emergency services and network operator; for gas, evacuate, remove ignition sources, ventilate and call the gas emergency line. For an intact unknown service, protect it from damage, review the drawings, re-scan with a locator, and contact the likely utility owner to identify and de-risk it. Do not resume until the service is identified and a safe method agreed.

What not to do

Do not assume a cable is dead or a pipe empty, do not attempt to move or repair a service, and do not dig on "to see where it goes". Do not ignore the discovery in the rest of the excavation, and do not rely on drawings that have just been proven incomplete. Do not use excavator teeth or power tools near an exposed or suspected service.

Who is responsible

The principal contractor and site management stop work, control the area and coordinate with the utility owner; the competent supervisor and operatives follow safe digging; the utility owner identifies the service and makes it safe. Designers and the temporary works process inform any change to the excavation method.

Evidence and records

Record the discovery or strike, the location and depth, the immediate actions, the utility owner contact and their response, the identification and de-risking, the revised permit and method, and any RIDDOR consideration for a strike. Update the site's services information and drawings so the record reflects reality.

Escalation

Escalate a strike to the emergency services and network/utility operator immediately, and treat injuries as potentially RIDDOR-reportable. Escalate a systemic records problem (services not where the drawings show) to the designer and client so the wider excavation plan is reviewed. Coordinate with trench support and, where the ground has also changed, the post-rain re-entry checks.

Prevention

Follow HSG47 every time: obtain and use utility plans, scan with cable and pipe locators, dig trial holes and use safe-digging practices, brief the crew, and permit the work. Treat records as a starting point, not a guarantee, and re-scan as the dig progresses. Good pre-dig information and safe digging prevent most strikes.

Where Complys can help

Complys can hold the site's services information, permits, RAMS and incident log, and keep the discovery-to-safe-method trail together. It does not locate or make safe buried services; the crew's safe-digging practice and the utility owner do. Ask the Complys team to show how permits, RAMS and incidents are tracked.