Contact with powerlines can result in death or serious injury for a worker. Supervisors and workers should assess the risks of working near overhead powerlines or underground electric lines before work commences.
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Electrical Exclusion Zones
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Contact with overhead or underground electric lines can have deadly consequences. Electricity can also arc across a gap if a person or equipment gets too close. Exclusion zones are the minimum safe distance from live power lines to reduce the risk of an electric shock. An exclusion zone distance depends on the competency and training of workers, the powerlines' voltage and whether the line is insulated.
Common incidents in the construction industry have resulted from trucks tipping loads, cranes and backhoes or excavators moving or working near live powerlines, setting up mobile concrete pumps or scaffolding too close to live powerlines, workers placing themselves or conductive material they are holding too close to powerlines, and digging trenches.
Supervisors and workers must assess and manage the risks of working near overhead powerlines or underground electric lines before work commences. The control measures must suit the level of risk to ensure workers and their equipment stay safe by keeping the correct distance from powerlines.
Workers may need to follow an electricity entity's requirements if they are responsible for the powerlines. To manage the risks, consider the following controls:
- Avoid working near or locating plant near live powerlines.
- De-energise powerlines prior to work commencing, or relocate them away from busy traffic areas.
- Use a safety observer on the ground to keep plant or equipment out of the exclusion zone.
- Arranging with an electricity entity to have flags or indicators placed on the overhead lines as visual markers, or locate the position of underground electric lines before excavating.
A safety observer's role is to prevent workers and equipment from entering an exclusion zone. They should have a clear view of the work being done and be trained to mark out and set up an exclusion zone, direct people, plant and vehicles to stop them entering an exclusion zone, and communicate effectively with a vehicle operator at all times. A safety observer should have their attention focused on their role and not do any other work that could compromise that, nor should they observe for more than one work situation at a time.
Reece operates his tip truck at a construction site near overhead powerlines. As his tipper raises to empty its load, it could enter an exclusion zone. Reece's supervisor notes two suitable control measures from the risk assessment. The first option is to de-energise the lines prior to the work being done. If the power cannot be turned off, he can use a trained safety observer to provide a warning if any part of Reece's truck enters the exclusion zone while the load is being tipped.
At a different location on the same site, Reece plans to use an excavator to dig a trench quite near to underground electric lines, but his machine will also be close to overhead powerlines. Reece's supervisor contacts Dial Before you Dig to locate nearby underground cables, and after potholing confirms the position of the line and marks the correct distance away from it to avoid digging in those areas. Reece briefs the safety observer regarding the safe distances to be kept from overhead powerlines and underground electric lines.
Make sure you're aware of the dangers of overhead and underground electric lines, and only work near them outside of the exclusion zone.
To help you assess the risks of working near powerlines, read the Electrical Safety Code of Practice 2020, Working near Overhead and Underground Electric Lines, available at www.electricalsafety.qld.gov.au
Work safe. Home safe.
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