Xcel Energy | Tips of the Trade

Understanding the tolerance zone

Review these tips with coworkers at your tailgate or toolbox meetings before work begins. This will help your crew avoid potential hazards when working near underground natural gas pipelines, electric power lines and other utilities.

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What is the tolerance zone?

The tolerance zone is a hand-dig zone that spans the width of a marked underground utility, plus a specified distance from each indicated outside edge of the utility. This specified distance varies from state to state. It is 18 inches in Colorado, New Mexico, South Dakota and Wisconsin; 24 inches in Minnesota and North Dakota; and 48 inches in Michigan. (Texas law does not specify this distance; however, 18 inches is a recommended best practice.)

In some (but not all) states, the law requires you to hand dig or vacuum excavate to expose and visually verify the location of all marked utilities before you can power dig in the tolerance zone. It is the excavator’s responsibility to know and follow state damage prevention laws. Learn more about your state's requirements at your state's 811 site. (Click your state's name below to link to your 811 service.)

Dig with care

When digging in the tolerance zone, use reasonable care and these nondestructive digging methods:

•	Hand digging with a blunt shovel. Never use a pickaxe or pointed spade, and never stomp on a shovel with both feet. That’s a sure way to damage a utility line. Instead, use a blunt shovel and a gentle, prying motion to break away soil as you approach the utility from the side.

•	Never pry against a utility line to remove soil.

•	Vacuum excavation. This method uses suction and water to quickly and safely remove soil. Be mindful of water water pressure; use lower pressure and tips with multiple nozzles.

Proceed with caution

Once you have exposed buried utilities, proceed with extreme caution. 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.

Would you like to know more?

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

Everyone's resources have been affected by the COVID-19 pandemic. You can help prevent located delays by pre-marking your proposed dig area in white and notifying 811 of your planned excavation with as much lead time as is possible in your state.

To learn more about Xcel Energy’s response to COVID-19, click here.

To reach your state's underground utility locate service/one-call center, call 811 or visit their online site by clicking on your state's name below.

The required "business day" wait time for each state is as follows (excludes weekends and legal holidays):

•	Colorado: 3 days
•	New Mexico : 2 days
•	Texas : 2 days

•	Michigan : 3 days
•	North Dakota : 3 days
•	Wisconsin : 3 days

•	Minnesota : 2 days
•	South Dakota : 2 days
•	Wyoming : 2 days

For more information on worker safety, visit xcelenergy.e-smartworkers.com.

In case of emergency, call 911 and Xcel Energy:

Electrical Emergencies: 800-895-1999

Natural Gas Emergencies: 800-895-2999

CO and TX only: Gas Transmission Pipeline

Emergencies: 800-698-7811

Xcel Energy is a founding member of the Gold Shovel Standard, which is a first-of-its-kind, two-part excavation safety program. The program both certifies an excavator's policies and procedures against the Gold Shovel Standard, and publishes a score or rating, known as an EICO™ score, which is an ongoing measure of an excavator's excavation-safety worthiness. It is a novel and ambitious program on a North American scale to dramatically reduce damages from excavation to buried asset networks. To find out more about the Gold Shovel Standard, please visit goldshovelstandard.org/industry/excavators.

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