The tolerance zone is a safety area that spans the width of a marked underground utility plus a specified distance from each indicated outside edge of the utility. This distance varies from state to state: It is 18 inches in Kentucky and Ohio, and it is 24 inches in Indiana, North Carolina, South Carolina, and Florida.

If you plan to dig or move earth in any way, notify 811 and then wait the required time before you dig. The 811 service will arrange to have buried utility lines located and marked by their member utilities, so you can dig a safe distance away. (The 811 center will let you know if you must contact non-member utilities to have their facilities privately located.)

Once buried utility lines have been marked, respect the tolerance zone to help protect these lines from excavation-related damage. Before you power dig in or near this zone, hand dig to expose all marked utility lines and visually verify their precise location. Use reasonable care and these nondestructive digging methods:

Proceed with extreme caution around exposed utility lines. Power digging equipment can damage a section of electrical conduit or pipeline in no time. Even hand digging can compromise buried utilities by removing supporting soil. Take all necessary precautions to protect buried utilities from damage.

Additional digging and overhead guidelines, case studies, instructional videos and training tools can all be found, at no charge to you, on Duke Energy's e-SMARTworkers website.

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