Spring is upon us and it’s that time of year again when the ground begins to thaw, and the flowers start to appear. It also means construction season will be ramping up across our province. Unfortunately, this is also the time of year Alberta utilities start to see an increase in the number of people coming into contact with underground power lines.
In 2015, there were 387 underground powerline contacts in Alberta. In Calgary alone, there were 65 incidents involving contacts with underground powerlines last year, which caused $244,000 in damages.
The best rule is to avoid digging around underground cables all together, but if you must work around them, there are ways that you can expose them safely.
Most utilities have an approved list of contractors who can work around live underground cables, provided they abide by the utility’s hydrovac / ground disturbance procedures. Before you start digging on any job site, you must request locates. The site of an underground electrical line will be marked with a red chevron. Compare the locate ticket and your work zone to ensure the markings match what is on the ticket. Then follow a few simple rules to help safely expose the lines.
- If you have to disturb the ground within one meter on either side of a chevron mark and the powerline is below 25kV, you must do so by hand, using a dry, non-conductive shovel or hydrovac. Continue by gently lifting the dirt and remove it in small layers until the line is exposed.
- Use a shallow angle if you’re using a shovel and do not step or jump aggressively on it. You run the risk of puncturing the lines below.
- In frozen conditions, a hydrovac is the safest way to expose live wires. Hydrovac operators must be aware of the proper safety procedures, as per Alberta Occupational Health and Safety (AB OHS), before attempting to expose a live wire.
- Once the line is exposed, you can then use mechanical digging equipment to dig near the line, provided you use a spotter to keep an eye on the line. The spotter should remain in constant contact with the operator, making sure the shovel remains at least 30 cm (one foot) away from the cable.
What do you do when you have your locates, you’ve taken all the steps required to expose the underground cables safely, and you still make contact? STOP ALL WORK IMMEDIATELY AND CALL 911.
If contact can’t be broken, stay where you are. If you can’t due to another emergency (like the vehicle being on fire), jump from the vehicle, landing on both feet at the same time. Then move 10 meters away from the vehicle in a hopping (with both feet together) or shuffling motion. If you are shuffling, never allow the heel of one foot to move beyond the toe of the other. Secure the site and wait for responders to arrive.
For more information on electrical line safety, watch this video and contact your local utility to learn more about safe digging procedures.