Working Safely in the Vicinity of Underground Electric Lines

By superadmin on October 16, 2018 in Blog

Each year, it’s estimated that up to 200,000 new homes are being connected to underground power supplies throughout Australia. This is especially the case in new subdivisions wherein underground power delivery is now compulsory.

After all, overhead power lines are traffic and tree hazards. Motor vehicle accidents (e.g. cars hitting the poles) led to injuries, fatalities and costly damages. As a result, there’s a growing incentive to placing the power lines underground.

What does this mean to construction, utility and excavation contractors? They now have to observe more safety precautions when working in the vicinity of underground electric lines. There’s a complex subsurface network of cables and pipes which the contractors and crew need to be aware of.

Working safely in the vicinity of underground electric lines

After the job site has been determined (site dimensions, layout, coverage), the next step is to identify the risks present in the area. The risks above the ground are often already apparent because these are visible (e.g. trees, other structures, presence of people nearby). Visual inspections will readily provide information about the above-the-ground risks in the area.

However, it’s entirely different when identifying the risks present underground. These are hidden from view and often, acquiring complete information might be more challenging. Take note that there could be a complex network of pipes and cables underground. Also, the buried cables might be in varying depths and these are covered in dirt (a crew member might accidentally hit an underground cable).

That’s why contractors and businesses involved in working in the vicinity of underground electric lines should possess a comprehensive underground utility map. Although there are visible markings that indicate presence of power cables, often these don’t follow a straight line. Natural occurrences and recent construction or excavation activities might have already caused the power cables to slightly shift. It’s also possible that some portions of the cables were slightly damaged thereby exposing workers to serious risks.

Contact with exposed energised parts may occur through the following scenarios:

  • A fencing contractor is digging holes or placing posts where an electrical cable is buried
  • A plumber is digging a trench to expose and locate underground water and sewer pipes
  • A mobile crane (or any other heavy vehicle) gets stuck in the area where there are underground power lines
  • A crew member is digging a hole using metal hand tools (e.g. shovels, spades, forks)

Whether the power lines are carrying a voltage of 230 volts or 400,000 volts, the risks are always serious and may result to injuries and fatalities. Add to that the potential tripping and falls of workers during and after an accident.

Aside from the potential electrocution, fire and explosion hazards could also be present in the site. That’s because the electrical charge might ignite the mixture of gases in a trench (or when there’s a gas pipe damage or leakage).

The size of the fire and explosion (or the severity of these occurrences) may depend on the gaseous mixture and the amount of flammable gases and combustible materials in the area. It’s best to identify and eliminate the risks early on before starting the work. Fires and explosions are difficult to contain once they start. Also, these could lead to injuries, fatalities and costly damages and interruptions to the residential and business community in the area.

Start with Dial Before You Dig

So how can we identify the risks? The starting point is contacting Dial Before You Dig (phone 1100 or contact them online). This service will then tell you if there are electrical cables owned by its contributory members present in the vicinity of your job site. You will get access to the contact details of the infrastructure owners relating to your enquiry. Then, you should contact them and hear from all of those asset owners before starting any construction or excavation activity. In cases wherein you’re excavating on a private property, you should first notify the owner or occupier of the premises before commencing your work.

We mentioned earlier that you should first contact all the relevant asset owners. However, the relevant infrastructure owners should have been first registered with Dial Before You Dig. If one asset owner was not registered (or some underground assets may have not been registered with Dial Before You Dig), you would have incomplete information about the area’s subsurface infrastructure. Also, it’s also possible that the registered asset owner doesn’t have a complete and updated map of the underground utilities. In other words, asset owners may not be able to pinpoint the exact locations of the underground utilities. As a result, you and your team will be exposed to unknown risks that could be equally or more dangerous.

That’s why the next step is to visit the job site and perform a complete inspection and assessment for the presence of unregistered subsurface assets. This way, you’ll acquire a complete and updated set of data and maps that clearly show the locations and depths of the underground power cables and other relevant utilities in the area.

The next steps for ensuring safety

It’s important that the actual positions of the underground assets are verified before commencing any excavation or construction activity on the site. A recommended way to accomplish this is by requesting the services of a certified locator and then performing excavation (slightly destructive or non-destructive) to record the asset’s current and accurate position.

For instance, here at One Search Locators our certified Service Locators mostly use electromagnetic equipment to determine the location of power lines. This is done by using a transmitter to send signals into the ground and then interpreting those signals upon their return. This method works well even in wet soil wherein the moisture can enhance the signal.

The result is a complete and comprehensive map of the underground electric lines (including the branching out and the depths of those cables). Our certified Service Locators will also label the areas where underground power lines are present. With these labels and information, the crew will avoid damaging or tampering the subsurface power cables during digging. The work will speed up while achieving better safety at the site.

For added verification, pot-holing can be performed to expose the cables and ensure their depths and positions. This usually involves digging with hand tools to verify the existence of assets in the location. There should be a pre-determined depth and insulated hand digging tools must be used. But before performing this pot-holing, a comprehensive and updated utility map should first be present. This way, pot-holing would be faster and more effective in verifying the locations of underground assets.

Further eliminating the risks

To absolutely eliminate all risks, the solution is to prevent those risky scenarios in the first place. In our case, the most effective way is to prevent people, tools and equipment from coming within the vicinity of the energised electric cables. This is to avoid direct contact with the power lines all together.

However, often crucial work is done near underground electric cables. It’s often the case in dense residential and commercial areas wherein underground power lines are already in widespread existence. What your team can do now is to know the location of those underground utilities, get knowledgeable about the risks (assume that there are always electrical safety risks) and then prepare yourself and your team.

It starts with determining the location of the underground assets that pose safety risks. Contacting Dial Before You Dig is only the first step. The information the registered asset owners will provide may not be enough to guarantee the workers’ safety when working in the vicinity of underground electric lines.

That’s why many contractors and professionals contact us here at One Search Locators. Our electricity line location service involves identifying and labelling any underground power lines in a given area, to ensure they’re not damaged or tampered with during construction. We use electromagnetic equipment to accurately locate the lines. Our certified Service Locators can be on site within 24 hours upon your request. This way, you can quickly plan for the excavation work and help improve your workers’ safety at the job site.

We have provided electricity line location services at Sydney, Newcastle, Wollongong, Melbourne and surrounds under a wide variety of industries. Our experienced team has already encountered a wide variety of scenarios and through the years, they’ve successfully provided a comprehensive and updated map of underground electricity lines. Contact us today and let’s discuss how to improve safety in your job site by first determining the location of power lines under the ground.