Wiring Factsheet

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The Institute of Electrical Engineers (IEE) provide a set of wiring regulations (known as BS7671 17th Edition) for electricians. These provide guidance for electricians to wire buildings in such a way as to avoid the danger of electric shocks for the people occupying them. The guidelines (which are not, in themselves, legally binding though do have legal implications) do not require low electromagnetic fields (EMFs).

Building wiring can be, and often is, responsible for high electromagnetic fields (EMFs) in the home, school and workplace. High levels of EMFs can aggravate, or even cause, a number of chronic health problems. You can use screened cables for wiring, but it is slightly more time-consuming and expensive to use than the ordinary type of cable, and most electricians do not see the need.

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, including on house wiring, may be found in this and in the supporting papers that are available from the Department of Health website. http://www.dh.gov.uk/en/Publichealth/Healthprotection/DH_4089500

Workplaces where there is heavy duty cabling involved in providing power for some processes can create very high EMFs. One factory near Liverpool had fields of over 1000 microtesla immediately above the cable, which crossed an area with no restrictions for workforce access.

Wiring used to be in metal 'conduits' (metal tubes that contained the cables). This generally resulted in very low EMFs. However, this was an expensive way of wiring a building, and was quite difficult to do. With the improvements in plastic technology, cables covered in plastic insulation were a much cheaper and easier way of installing electric power in a building. This became the 'norm'.

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 faulty wiring lighting circuits as well, especially in lights with "two-way" switching.

Hand-held, easy-to-use meters that will accurately measure both electric and magnetic fields such as the EMFields-PRO or ELF-GS3030B are available to hire or buy in the UK from EMFields.

Hand-held, easy-to-use meters that will accurately measure both electric and magnetic fields such as the EMFields-PRO or ELF-GS3030B are available to hire or buy in the UK from EMFields.

Ideally the field levels in your home should be no higher than 0.1 microtesla (magnetic field) and 5 volts per metre (electric field), preferably less. Some lighting circuits for fluorescent or halogen lights can create high EMF levels not only in the room in question, but also in rooms above.

If changes are made to any part of wiring, by an electrician, then they have to sign off the whole of that circuit as meeting the appropriate regulations. Note that it is now illegal to re-wire someone else's property, without having the correct qualifications, or having the work formally inspected when complete and before "making live". (Building Regulations Part P)

It is legal to re-wire your own property, but the work must be formally inspected when complete and certainly before the house is sold or let (Building Regulations Part P). We have found very high EMF levels indeed in houses where people with little understanding about EMFs have carried out the work.

Demand switches (to reduce the exposure to EMFs at night) on lighting circuits are unnecessary if the house is wired for low EMFs. Installing demand switches on power circuits are more difficult because of the appliances (e.g freezers) which are meant to be on all the time.

Illnesses such as cancer and depression, are associated with living in electromagnetic fields above 0.2 microtesla (magnetic field) and ME has also been linked with high electric fields (measured in volts per metre).

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