The most common queries we receive concern Electric & Magnetic Fields (also called EMFs) and their possible health effects.

EMF defined

In basic terms, an EMF is present where ever electricity occurs.

EMFs occur both naturally and from man-made objects. For example, the Earth's magnetic field is produced by electric currents circulating in our planet's core. Man-made EMFs are created by things as diverse as electrical power systems and kitchen appliances, e.g. toasters.

Decide for yourself

A debate about the possible harmful effects of EMF on humans and animals has continued since the 1970s. Despite extensive worldwide authoritative research, no conclusive evidence has been found that the EMFs caused by power systems result in disease.

However, we do not want to tell you what to think about EMFs. We invite you to reach your own conclusions.

To help you do so, we are collecting information from independent sources to share with you. We will then publish it on this website. We expect this process to be complete by July 2008.

You can then explore these details and decide for yourself if EMFs are a problem. We are confident that you will discover there is little to fear.

Clear, plain English

Most research into EMFs is published in scientific or engineering journals. As such, we will simplify some of the language to make it easier for non-specialists to understand. However, all the key points remain.

We will not remove any data.

If you want to read further or examine the original research, links to scientific papers will also be included.

Our promise to you

We want to give you everything your need to make up your mind. Therefore, we pledge to constantly review this area.

Your health and safety are absolutely fundamental to how we work. We are committed to operating our network in full compliance with international guidelines and recommendations.

For more information about EMFs and their possible health effects.

Electric and Magnetic Fields (EMFs) are not only a man-made phenomenon. They have always existed. In fact, you are completely surrounded by natural EMFs.

EMFs in nature

Sunlight is the most obvious example of an EMF. This field (in the form of light and heat) provides the energy for most life on our planet.

The earth itself also produces an EMF from deep within its core. This field gives rise to the north and south poles, which allow for navigation by compass.

Finally, your own body creates an EMF. This is generated by the electrical signals that constantly flash through your nervous system.

Of course, EMFs are also created by artificial objects. Anything with an electrical current will produce an EMF. This includes hair dryers, televisions, car batteries and electricity powerlines.

EMFs in more detail

Before we get into the detail of EMFs, let us first define some of the terms we are using.

• A field: This term describes the influence an object has on a surrounding space. For example, the ‘temperature field’ that surrounds a hot water pipe has a heating effect. It can heat up nearby walls.
• An electric field: An electric field is produced when voltage is applied to a conductor. For example, when you plug the cable from a toaster into a socket an electric field is created in surrounding air. The higher the voltage, the stronger the field.  
• A magnetic field: A magnetic field is produced by a magnetic object. Although magnetism appears to be natural to some items (e.g. in the mineral Magnetite), it occurs most frequently when an electrical current flows through an object. For example, an electromagnet creates a magnetic field around itself when a current is applied. This field can then interact with nearby objects, e.g. to lift metal objects.

Differences between electric and magnetic fields

There are some important difference between electric and magnetic fields.

For example, electric fields can be blocked very easily by buildings, hedges, fences, trees, etc. As a result, very little energy from any electric fields outside a house (e.g. from a powerline) can penetrate inside it.

By contrast, magnetic fields are much harder to screen and not generally screened by buildings.

Another difference is that electric fields are created whenever an appliance (such as a radio or TV) is plugged in. The appliance does not have to be turned 'on' in order to produce the electric field. The field is created because a voltage is present.

However, magnetic fields are only produced when an appliance is turned on and electric current is flowing.

Electromagnetism, your bicycle and EMFs

You can see that electric and magnetic fields are very tightly linked. In fact, they are just 2 aspects of a single force called electromagnetism.

Electromagnetism is what allows us to create electricity from a magnet (or to create a magnet from electricity).

The classic example of electromagnetism is a bicycle dynamo.

When you pedal a bicycle, it causes a magnet to spin every quickly inside a coil of tightly wrapped wire. The spinning magnetic field causes the electrons in the wire to move. This creates electricity, which in turn lights the lamp. (The same electrical current also causes an electric field to be generated).

The opposite is also true.

Spin a coil of tightly wrapped wire carrying an electrical current around a piece of iron, and it will be magnetised. (It also causes a magnetic field to be created).

As you can see, in both instances an EMF has been generated by the dynamo. This EMF surrounds and penetrates your body.

Measuring EMFs

Even though a bicycle dynamo may be very close to you, the risk posed by its EMF is insignificant. This is because the strength of the fields is tiny.

To measure the intensity of an EMF, you need to evaluate 2 factors:

1. How far are you from the object that creates it?
2. How strong is the field that surrounds you?

The importance of distance

An important characteristic of EMFs is that their strength diminishes as you move away from their source. This is similar to the way that the heat from a candle diminishes as you move away. 

The Irish electricity system is designed to ensure that the EMF exposure of someone standing directly under an electricity line (i.e. at a short distance from an EMF source) is well within international and EU guidelines.

Measuring EMF strength

The strength of an EMF can be measured in 3 ways.

1. Electric field strength

This field is measured using ‘Volts per metre’ or V/m (thousands of volts per metre = kV/m).

2. Magnetic field strength

This field is measured using a scientific quantity called ‘Magnetic flux density’, expressed in the unit ‘Tesla’ or T.

3. Frequency

Another—and more fundamental—way to measure both electric and magnetic fields is to calculate the ‘frequency’ of the electromagnetism that underlies them.

The force of electromagnetism is carried in ‘waves’ at the speed of light. These waves have ‘peaks’ and ‘troughs’ – just like a water wave.

In a ‘high frequency’ wave all the peaks and troughs are packed closely together. As a result, they carry lots of energy.

In the ‘low frequency’ wave, the peaks and troughs are spaced out. As a result, they are low in energy.

Basically, the higher the frequency of an electromagnetic wave, the more powerful the resulting electric or magnetic field becomes.

Frequency is measured in a unit called Hertz (Hz).

EMF risks, strength & distance

The frequency of the Electric and Magnetic Fields (EMFs) created by the electricity system in Ireland is 50 Hz, i.e. 50 waves per second.

In comparison with other types of electromagnetic waves, this is extremely low. This is illustrated in the diagram below.

Since the frequency of the electromagnetic waves is so low, the strength of the resulting EMF is also low.

[Types]	Electric field strength (kV/m)	Magnetic flux density (Micro Tesla)
International guideline reference limits	5 kV/m	100 or 100 millionths of a Tesla
400kV powerlines (biggest in Ireland)	1.29 kV/m	1.81 or 1.81 millionths of a Tesla
220kV powerlines (single circuit)	0.359 kV/m	0.71 or 0.71 millionths of a Tesla
110kV powerlines (single circuit)	0.08 kV/m	0.2 or 0.2 millionths of a Tesla

Research into EMFs

Millions have now been spent on research into EMFs and human health. No conclusive evidence has been found that such fields are harmful, at levels to which you can expect to be exposed.

This view is shared by many respected international organisations, including the World Health Organisation. The Department of Communications, Marine & Natural Resources and the EU also agree that - based on the balance of evidence - EMFs do not have any adverse effect.

Both these bodies recommend compliance to the international guideline exposure limits set by the International Commission for Non Ionising Radiation (ICNIRP). These guidelines are designed to limit human exposure to electromagnetic fields.

The guidelines have become the international standard for EMF safety. The ICNIRP guidelines are reviewed on a regular basis and were endorsed by the World Health Organization’s most recent EMF report in 2007.