Safety Measures for Underground Electrical Lines

Recently some businesses in Baltimore County experienced power outages after a contractor stuck an underground electrical line, according to the Baltimore County Fire Department.

Twelve businesses were affected by the damaged electrical line and several have been shut down from smoke and other issues, the fire department reported.

There are specific guidelines for avoiding underground utility lines including:

Always verify underground lines, using surface markings, before drilling vertically or horizontally to avoid hitting them.  Since underground lines can be difficult to identify if they are covered by other lines, are undocumented, are buried at depths different from code requirements, or are in a different position from initial installation due to ground settling, it is important to use multiple identification and verification methods before drilling.

Horizontal Directional Drilling

HDD is a trenchless technology that uses surface-launched equipment to drill underground horizontally and install pipes, conduits, and cables. HDD is used in several industries, such as utilities and telecommunications, at sites with limited space such as dense, urban areas, or where traditional vertical excavations are too hazardous.

Although HDD technology is thought to take less time, require fewer workers, and cause less surface damage compared to traditional open trench excavations, it is thought to be more difficult to avoid utility lines when using HDD because of the limited visibility inherent to the process.

The risk of striking underground natural gas or electric utility lines increases when HDD is used in urban areas. To verify and avoid underground utility lines when using HDD:

  • Visually inspect the entire planned digging path for structures that indicate potential underground utilities such as gas meters and manhole covers.

Underground service locators typically cannot provide depth information for utility lines. Employers must implement safe work practices that always verify the depth of utility lines near the planned drill path to prevent hitting them.

  • Review drawings and contact utility companies directly, whenever possible, to verify underground utility locations.
  • Compare findings with surface markings to identify any missed utility.
  • Employ potholing and other safety precautions described below to further identify and avoid lines in the drill path.
  • Use site-specific safety assessments to determine appropriate drilling techniques and safety practices, such as when potholing, drilling the bore, or using a back reamer.
  • Contact the local utility location service to mark lines and assist with determining utility locations. ¬†Compare drawings with surface markings, as some utility lines may miss detection or may be missing from utilities maps.
  • Review drawings and contact utility companies directly, whenever possible, to verify underground utility locations.
  • Ensure that the HDD machine operator and tracker walk through the planned drill path during planning and site preparation. Check for gas meters and manhole covers that may indicate an underground utility line, obstructions along the drill path, and potential sources of interference that could affect tracking device readings.

For more construction safety information, contact our offices at Diversified Safety Services.



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