Operating cranes and mobile plant in the vicinity of overhead electric lines
Contact with overhead electric lines is a serious risk when operating a crane or other plant as it can be extremely difficult for crane or plant operators to see or judge distances from them.
Actual contact with the lines is not needed to deliver an electric shock, as a close approach to the line conductors may cause a 'flashover' or arc.
Before operating a crane or item of mobile plant, a worksite inspection should be conducted to identify potential hazards such as overhead electric lines or other electrical equipment. A risk assessment should include:
- the location and voltage of the overhead electric lines
- the nature, size and shape of the load to be moved
- the setting up and packing up processes
- the type of crane, mobile plant, machinery and equipment used and its design envelope
- the stability of crane or mobile plant and suspended loads
- site conditions, including unexpected movement of the terrain, ground or surface upon which the crane or plant is located
- the prevailing and unexpected wind strength and direction and weather conditions
- the qualifications, competency, skill and experience of people doing the work
- traffic or pedestrians that could interfere with the work
- the minimum clearance distance from the closest part of the crane or other operating plant to the electric line
- whether the load is being carried above the electric lines and may accidentally fall onto the energised lines
- the possibility of sway and sag of the overhead electric lines
- the possibility of the crane or plant becoming energised through voltage induced by adjacent electric lines, especially high voltage lines
- how the load being carried by a crane is secured and whether any part of the load may inadvertently move during the operation and encroach on the authorised person zone
- the potential for inadvertent movement of the crane or mobile plant, the load, people and electrical equipment in the area
- the functional behaviour of the crane, load or plant that could result in inadvertent contact with overhead electric lines.
Electric lines should always be treated as energised unless the operator of the crane or mobile plant has received an access authority or other form of written documentation from the electricity supply authority which allows people to work within the no-go zone.
Approach distances for work performed by unauthorised people
|Nominal phase to phase AC voltage (volts)||Approach distance (metres)|
|Up to and including 132,000||3.0|
|Above 132,000 up to and including 330,000||6.0|
|Nominal pole to earth d.c. voltage (volts)||Approach distance (metres)|
|Up to and including +/- 1500 Volts 3.0||3.0|
There are two options for operating a crane or mobile plant in the vicinity of overhead electric lines:
- have the electric line de-energised, or
- stay outside the authorised person zone.
For more information on working safely near overhead power lines, visit www.worksafe.qld.gov.au or call the Workplace Health and Safety Infoline on 1300 369 915.