Safe Digging Guide: Working Around Buried Utilities

Every excavation should start with a utilities search. Request plans from all relevant asset owners, including electricity, gas, water, telecoms, and any private services that may be present.

Utility plans show approximate positions only. HSE guidance is clear that plans should be used for planning purposes, but the actual location of services must be confirmed before excavation begins.

Consider the limitations of utility records. Services may have been installed, diverted, or abandoned without plans being updated. Always assume that uncharted services may be present.

Your risk assessment should identify all utilities that may be affected, the excavation method to be used, and the precautions required to prevent strikes.

Cable avoidance tools (CAT) and signal generators (Genny) are essential equipment for any excavation. Operatives should be trained and competent in their use.

Radio mode detects signals from live power cables, but will not find dead cables or other utilities. Signal mode, used with a Genny, can trace metallic services more precisely.

Ground penetrating radar (GPR) provides additional detection capability, particularly for non-metallic services like plastic water pipes. It is increasingly used for surveys in congested areas.

No detection method is infallible. The location of services should be confirmed by careful excavation before any mechanical plant is used in the vicinity.

Hand digging remains the default method for final exposure of utilities. However, it is slow, physically demanding, and still carries some risk of tool strikes.

Suction excavation offers a safer alternative. By loosening soil with air or water and removing it by vacuum, the risk of striking utilities with a digging tool is virtually eliminated.

Mechanical excavation should only be used once the location of all services has been confirmed and adequate clearance is available. Even then, a banksman should guide the operator.

Whatever method is used, excavation should proceed cautiously as the expected depth of utilities is approached. Many strikes occur because operatives assume services are deeper than shown on plans.

HSG47, published by the Health and Safety Executive, provides authoritative guidance on avoiding danger from underground services. It should be familiar to anyone planning or supervising excavations.

Under the Construction (Design and Management) Regulations 2015, designers, principal contractors, and contractors all have duties to manage the risks from buried services.

The Electricity at Work Regulations 1989 place specific duties regarding work near electrical services. Accidental damage to cables can result in prosecution.

Civil liability for utility strikes can include the cost of repairs, compensation for service outages, and damages for any injuries caused. Prevention is always more economical than remediation.