Our electricity supply comes to us from a generating station, by means of powerlines. The majority of these are overhead cables, supported by large transmission towers or pylons. The cables emit magnetic and electric fields. Powerlines carrying smaller loads to meet local power needs are supported on smaller metal towers or wooden poles. Housing developments are often built near an existing line. Power cables can be routed above, or sometimes fixed to, houses.
The distance you need to be away from powerlines depends on how large the load is and whether the load is balanced. You also need to take into account the geography of the local area. Underground cables also emit high magnetic fields, which can extend outwards for a considerable distance. Due to the varied and often unpredictable paths that electric currents in our electricity systems use it is not possible to calculate the field levels in a typical situation. The only way of knowing your exposure is to actually measure the fields and compare them with the average magnetic field level of not more than about 0.05 microtesla for a UK home. There are other potential harmful effects from the electric fields, as revealed in research at Bristol University.
The Stakeholder Advisory Group on ELF EMFs (SAGE) was set up by the Department of Health to explore the implications and to make practical recommendations for a precautionary approach to power frequency electric and magnetic fields. It has now produced its first report, and more information is available from the Department of Healthwebsite.
This was followed by a "Cross-Party Inquiry into Childhood Leukaemia and Extremely Low Frequency Electric and Magnetic Fields (ELF / EMF)", which was set up to allow the five Members to consider in detail the evidence for an association between Electric and Magnetic Fields (EMF) from High Voltage Overhead Transmission Lines (HVOTL) and an increased risk of childhood leukaemia and determine what should be done. Their findings and recommendations can be found on the ePolitix.com website.
Substations transform the voltage from long-distance high voltage powerlines to the supply level we can use in our homes. Electric and magnetic fields are generated by the equipment inside the s
ubstation or transformer and the cables going in and out. Sometimes substations are interconnected in such a way that high magnetic field levels are created in a wide area, affecting many houses, especially those with small or no front gardens. Again, the only way to know what field levels you are exposed to is to measure them - is it impossible to give an accurate calculation or estimation.
The way that buildings are wired can produce high electromagnetic fields (EMFs) in the home, school and workplace. Even recently re-wired buildings can lead to problematic levels of fields, as wiring for low EMFs is not covered in the IEE wiring regulations. High magnetic and electric fields are commonly found near walls, ceilings of downstairs rooms, and the floors of upstairs rooms.
In the UK, buildings usually have 'ring' circuits feeding the power sockets. These circuits always give rise to higher magnetic fields than 'radial' or 'tree and branch' wiring, which are commonly used in other countries. High magnetic fields can be caused by lighting circuits as well.
Ideally the field levels in your home should be no higher than 0.1 microtesla (magnetic field) and 5 volts per metre (electric field).
Common electrical appliances used in the home can give off high electric and magnetic fields. Night storage radiators, clock radios, hairdryers, cordless phones, electric blankets, baby monitors, burglar alarms, computers and VDUs, cars, cookers, dishwashers, fridges, washing machines, tumble driers, vacuum cleaners, TVs, meter cupboards, fluorescent and halogen lights, etc. have all been associated with concerns about potential health effects, due to high EMFs. These appliances are very varied in their designs, with different models which change regularly.
ELECTRIC AND MAGNETIC FIELDS
There are serious health effects, including cancer and depression, associated with living in electromagnetic fields above 0.2 microtesla (magnetic field) and also with high electric fields (measured in volts per metre). Electric fields from sources outside the home are stopped by many materials (including brick and wood), but can be produced by the wiring inside. Magnetic fields are produced by wiring and electrical appliances and as well as being localised, they can also travel through walls, etc., only reducing with distance. It is important that your electromagnetic environment (at home, school and in the workplace) does not expose you to the risk of adverse health effects people report.
In our experience about 50% of homes have higher than desirable magnetic fields due to the way they are wired and some appliances located close to beds etc. It is important to measure the electromagnetic fields to make sure that the levels you sleep and live in (including the garden) are low enough so that you and your family are not at risk.
Our meters measure both electric and magnetic fields, and give an instant readout. They come complete with straightforward instructions, and comparison levels to see how 'safe' your readings are.
In our experience more homes have higher than desirable magnetic fields due to wiring faults and some appliances located close to beds etc. It is important to measure the electromagnetic fields to make sure that the levels you sleep and live in (including the garden) are low enough so that you and your family are not at risk. Our meters measure both electric and magnetic fields, and give an instant readout. They come complete with straightforward instructions, and comparison levels to see how 'safe' your readings are.