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Working near underground utility cables

Underground electric cables are a hidden danger. Unlike working around overhead lines, workers are unable to see if they are getting too close to a cable. They must rely on an underground cable locator (locates) to assist with locating buried power lines and other underground cables.

Safe digging practices must be adhered to when dealing with underground cables and construction to keep everyone safe.



Locate buried utilities

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Dig safely

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Horizontal directional drilling

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  Locate buried utilities

Prior to any excavation, make sure all buried utilities in the area have been located.

  • Click before you dig or call Alberta One-Call at 1 (800) 242-3447. Locates can take one to two weeks. Please ensure these timelines are included in your work schedule.
  • Ensure that your work site (digging area) is reflected accurately on the locate ticket.
  • After processing your request, Alberta One-Call will notify registered underground facility owners of your project. Their representatives will be sent to the worksite to locate and mark underground utilities with coloured locate markers, stakes, flags or paint.
  • Electrical lines will be marked red, but it's important to know the dig safe colour codes, and the meanings of all the different colour codes for all underground hazards.
  • Note: Private utilities are not coordinated by Alberta One-Call. It's the contractor's responsibility to locate secondary services on commercial, multi-family and industrial sites.

Locate buried utilities

Call Alberta One-Call. Locates will take one to two weeks. Please ensure these timelines are included in your work schedule.

Ph: 1 (800) 242-3447
Website: Albertaonecall.com

  Dig safely

Here is what you need to know about if your proposed dig zone is near underground power lines/cables. If you have any questions about the information below, please contact EPCOR at (780) 412-4500 and ask for a referral to a Safety Codes Officer.

Distribution cables

  • No mechanical excavation is allowed within 1 metre of the locate marks for underground distribution power lines. Workers must hand-expose or hydrovac all utilities within this zone.
  • For underground distribution lines only, once the line is exposed, you can use mechanical digging equipment to dig near the line. Always use a spotter to make sure your equipment stays at least 30 cm (1') away from the line.
  • The depth of buried utility lines and number of cables will vary. Freezing conditions in the fall and winter followed by the spring melt can impact the grading of soil. As a result, the soil can compact and cause power lines to migrate to shallower ground. Use caution and ensure the hand-dig zone is large enough to expose all cables in your dig area.
  • If the dig site requires you to suspend large sections of distribution cable (greater than 2 metres), notify EPCOR's Power Emergencies at (780) 412-4500 and they will put you in touch with a Safety Codes Officer. The cable may have to be de-energized or supported to prevent physical damage and ensure your safety. 
  • Be aware that high voltage equipment (such as a transformer or switching cubicle) has a ground grid around it that may not be marked by locators. Maintain a 2 metre safe zone around this equipment.
  • Distribution cables must be covered with a minimum 30 cm of sand prior to backfilling procedures.
  • For your safety do not handle or manipulate any underground cable. This may cause the cable to fail which may result in injury or death.

Transmission cables

If your proposed dig zone is within 30 metres of underground transmission lines, the following message should appear on your locate sheet: ""CONFLICT" NO GROUND DISTRUBANCE UNTIL CLEARED BY EPCOR TRANSMISSION. ARRANGE FOR SUPERVISION". 

  • Absolutely no ground disturbance of any kind (hand, mechanical or hydrovac) is to take place within this 5 metres of a transmission cable before your work is cleared by EPCOR Transmission. EPCOR Transmission can be contacted at the phone number listed on your locate sheet.
  • For underground transmission cables, contractors shall follow the direction provided by an EPCOR Transmission representative.
  • The depth of buried utility lines and number of cables will vary. Freezing conditions in the fall and winter followed by the spring melt can impact the grading of soil. As a result, the soil can compact and cause power lines to migrate to shallower ground. Use caution and ensure the hand-dig zone is large enough to expose all cables in your dig area.
  • If your work requires an underground transmission line be exposed more  than 5 metres, EPCOR Transmission is to be contacted at the phone number listed on your locate sheet 30 days before the work is to start.
  • Transmission cables may only be backfilled under the direct supervision of EPCOR Transmission and EPCOR's applicable standards. If you require specific instruction from EPCOR for backfill requirements, contact EPCOR Transmission at the phone number listed on your locate sheet.
  • For your safety do not handle, manipulate or walk on any underground EPCOR Transmission cable. This may cause the cable to fail which may result in injury or death.

Safe excavation requirements in Alberta

Find more information on the safe excavation requirements in Alberta in these sections of the Alberta Occupational Health and Safety Code, Part 32 Excavating and Tunnelling:

  • Disturbing the ground (Section 441)
  • Locating buried facilities (Section 447)
  • Exposing buried facilities (Section 448)
  • Consult the Alberta Electrical and Communication Utility Code for excavation work in the vicinity of underground power lines (Section 2-020).

  Horizontal directional drilling

Horizontal Directional Drilling (HDD) or horizontal directional boring is often used for installing infrastructure such as cable, ducts, water, gas and telecommunications lines, particularly in heavily developed industrial and urban areas.

Horizontal drilling has some potential advantages, including cost-reduction; shorter completion times; and less disruption to traffic, property, and the environment. However, the risk to workers in the event of a power cable strike is high. If there is a cable strike, the current will travel from the point of contact to the equipment. The equipment itself (and the ground around it) has the potential to become energized for up to 10 metres, endangering anyone nearby.


 

How we can help you work safe

If you are working within 7 metres of our overhead power equipment or digging within 1 metre of underground distribution power equipment, please take the time to do it safely. Familiarize yourself with the Alberta safety codes.
Find out how we can help

 


Disclaimer

This webpage provides information regarding safe work practices in relation to EPCOR power facilities. Employers and contractors have responsibilities under the Alberta Occupational Health and Safety (Alberta OHS) Act, Code, and Regulation. When there is a conflict between this document and any bylaws, legislation, or regulation, the relevant law prevails. Any reliance placed on this information is strictly at your own risk. EPCOR does not assume any responsibility or liability for any action, loss or damage that arises out of, or is in connection with the information contained in this webpage.