1. What is EMF?
Electrical energy involves ‘voltage’, which is the pressure behind the flow of electricity that produces an electric field, and ‘current’ is the quantity of electricity flowing that produces a magnetic field. Electric fields are naturally occurring and can be present in any appliance plugged into a power point and switched ‘on’ (however as electric fields are readily shielded they were not modelled for this proposal). Magnetic fields are only present when electric current is flowing. The strength of a magnetic field depends on the size of the current. Like electric fields, the strength of magnetic fields drops off quickly as you move away from the source.
2. What will the magnetic fields be in my street?
Ausgrid models the magnetic fields that would be found around the proposed cables once they are in service. Modelling is generally prepared using time weighted averages of the electrical load under future loading conditions. The magnetic fields are calculated using time weighted averages on the cables once they are in operation. The modelled magnetic fields are what the Australian Government agency ARPANSA identifies as typical background levels (01.- 2mG).
Magnetic field modelling assists Ausgrid with route planning, in providing information to the community, and as part of preparing the project’s environmental assessment. Independent modelling by consultant Magshield shows that the magnetic fields from the proposed new underground 33,000 volt cables for this project would cause no change to the existing magnetic fields both standing over the proposed cables (measured at 1 metre height) and at properties along streets along the proposed route. The magnetic fields from the joint bays would be higher but would drop down to everyday levels and property boundaries along the route.
3. Where can I get more information on EMF?
Ausgrid can provide more information on magnetic fields generally and in relation to this project. We can also organise visits to take measurements of existing magnetic fields in and around homes. Ausgrid has found on similar projects that this can provide some context to the magnetic fields from the proposed cables in relation to the existing environment. Further information can also be found at Australian Government agency
ARPANSA, the Energy Networks Association (ENA) and the World Health Organization (WHO).
4. Will the levels of electric and magnetic fields (EMF) from the proposed cables be safe and comply with relevant Australian health guidelines?
Safety is Ausgrid’s highest priority. The proposal has been planned on the basis that the new cables can be operated safely in the community and this is Ausgrid’s first and most important consideration. The new cables would operate well within Australian and international health guidelines, with very little, if any change to existing magnetic fields in nearby properties.
5. What is Ausgrid’s approach to EMF?
While there remains a lack of scientific consensus about whether electric and magnetic fields (EMF) can cause any adverse health effects, Ausgrid understands that there is concern in the community about EMF. We take seriously our responsibility to help address these concerns by providing balanced and accurate information about EMF, by taking reasonable steps to limit exposure and by operating all our electrical installations prudently within Australian health guidelines. We also regularly monitor research and policy into EMF and health. As there is a lot of research and studies regarding health and EMF, Ausgrid is guided by Australian Government agency ARPANSA, which takes a whole of science approach in relation to electricity and health. This includes implementing prudent avoidance measures where practical and feasible, as we will do for this project. Ausgrid's position includes complying with all relevant national and international guidelines.
6. What is the difference between EMF and *mG on your documentation?
Electric and magnetic fields (EMF) are part of the natural environment and are present in the earth’s core and the atmosphere. These fields are also produced wherever electricity or electrical equipment is used. Magnetic fields are only present when electric ‘current’ is flowing. The strength of a magnetic field depends on the size of the current. Like electric fields, the strength of magnetic fields drops off quickly as you move away from the source. While electric fields can be shielded, magnetic fields pass through most materials. As electric fields are naturally shielded, the electricity network generally contributes very little to the electrical fields measured inside a home or office building. For this reason most discussion on EMF usually focuses on magnetic fields. A milliGauss (mG) is the unit of measurement for magnetic fields. When we are talking about EMF in this context, we are generally talking about magnetic fields and the mG is the measurement of these fields.
7. Do magnetic fields accumulate?
Adding magnetic fields from two sources is not a straight forward matter of adding the field strengths. Magnetic fields are vectors and have direction and size. Usually, if two fields come from different sources, the orientation is random and will vary over time. If there are two magnetic fields with random orientation, one field has to be only slightly larger than the other to dominate the average result. For example, if one field is half the size of the other field, it makes only a 10% difference to the total. Therefore, in practice, if we want to know what the field is at a given place, we need usually assess the field from the biggest single source only.
8. What is the acceptable range for magnetic fields?
In the absence of a current Australian standard, Ausgrid follows the current international (ICNIRP) guideline level of 2000mG. It is important to recognise that the numerical limits are based on established health effects. ICNIRP’s fact sheet on the guidelines notes that: “It is the view of ICNIRP that the currently existing scientific evidence that prolonged exposure to low frequency magnetic fields is causally related with an increased risk of childhood leukaemia is too weak to form the basis for exposure guidelines. Thus, the perception of surface electric charge, the direct stimulation of nerve and muscle tissue and the induction of retinal phosphenes are the only well established adverse effects and serve as the basis for guidance.”
9. Should I be concerned about magnetic fields from high voltage cables and links to childhood leukaemia?
Ausgrid’s position on EMF has been adopted in the light of authoritative reviews having concluded that no adverse health effects from exposure to EMF have been established, but recognising that there is, within the community, some genuine public concern about the issue which must be addressed. A further consideration is also the low levels of magnetic fields modelled for the new cables, which are well within the range normally encountered in everyday life at properties along the cable routes.
10. How high would the magnetic fields be on the Foord Avenue footbridge compared to the existing overhead power lines?
Modelling from the magnetic fields from the proposed new cables under the bridge indicate levels are well within international and Australian guidelines.
11. What would the magnetic fields be from the cables if they were installed in this lane way as it is very narrow?
Independent modelling has found that that the magnetic fields from the proposed new cables would be consistent with the existing environment at all properties.
12. What would the magnetic fields be from the joint bays?
While magnetic fields are typically higher at joint bays than in other sections, it is still expected that given the setback from the joint bay to property boundaries, the magnetic fields from the proposed new cables would be consistent with the existing environment.