March 2021

Going Underground

Whenever we break the surface of the ground, we should be mindful of what lies beneath us.

  • We might often think about underground services such as electric, gas and water when digging trenches and pits, but we mustn’t ignore the effects of ground compaction from heavy plant.

No matter where we are working, we must consider the presence of underground services. In remote areas the risk is reduced, but not eliminated. For every site we work on we should have been provided Pre-Construction information, Service diagrams or Hazards and Constraints Maps. These should show the presence of any underground services but cannot be taken as the sole sources of truth. There are other sources of information to consider. Dial before you dig services are a good source of information. Local knowledge can also help identify services not installed by utility companies. Finally use visual observations, if there is a phone mast near by it will need power, the red/orange markers posts mark out the line of high pressure gas lines and look for smaller ground markers for other cables and pipelines.

Any work that could disturb underground services must be properly risk assessed and planned. Where required, the owner of the service must be contacted to agree working methods, e.g. crossing high pressure gas pipes. When excavating around known services their position must be confirmed by the use of CAT and Genny equipment and/or digging trial holes by hand. Agree safe digging practices. Whenever possible, services should be made dead before excavating around them.

People each year are killed and injured striking underground services. This is a risk we can and must control by good planning and working practice.


  • Always locate the position and depth of services when excavating.
  • Only trained and competent people can use CAT and Genny equipment.
  • Always agree safe digging practices before starting excavation, note on Permit to Dig.
  • Only authorised persons can issue Permit To Dig.
  • Services don’t always run in straight lines.
  • Cables often have a coil of spare length at the bottom of poles.
  • Services are not always as deep as you expect.