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Electric & Magnetic Fields (EMF)Print this page 

 

 

What is EMF?

Electric and magnetic fields (EMF) are present everywhere in our environment but are invisible to the human eye.
Earth is a natural source of EMF; lightning is a product of electric field build-up during thunderstorm, compass needle is oriented by earth magnetic field.
Electricity, microwaves and radiofrequency fields are man-made sources of EMFs that form a major part of our modern life. Power frequency (50Hz in Malaysia) EMF is associated with electrical apparatus including power lines, underground cables and home appliances.

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How do these fields behave?

Electric Fields

Electric fields are created by voltage. The higher the voltage, the stronger the electric fields. You will find an electric field near any electrical appliance that is plugged in, even if it is not operating. Electric fields are strongest closest to their source.

Magnetic Fields

Magnetic fields are created by current or electricity flowing through a wire. Magnetic field strength increases with current, so you will find a stronger magnetic field near an appliance when it runs on “high” than when it runs on “low.” An appliance must be plugged in and operating to create a magnetic field. Magnetic fields are also strongest close to their source.

The following table provides comparison between electric and magnetic fields.

emf

Electric Fields Magnetic Fields
Produced by voltage (pressure which forces electricity along wires). Produced by current flow (when the apparatus is switched on)
Measured in volts per meter (V/m) or in kilovolts per meter (kV/m). Measured in gauss (G) or Tesla (T).
Easily shielded (weakened) by conducting objects such as trees and building. Not easily shielded (weakened) by most material.
Strength decreases rapidly with increasing distance from the source. Strength decreases rapidly with increasing distance from the source.

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How are we exposed to power frequency EMF?

Everyday, we are exposed to the magnetic field at home, office or in an industrial environment. This is because of our close contact with the electrical appliances and machinery around us. And since these machinery draw a large amount of current when they operate, they do produce some level of magnetic field.

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Does this affect us?

Studies and researches conducted internationally by expert and recognized agencies over the years have shown no firm evidence of a link between EMF from power lines or other power supply installations and any acute or long-term effect on human health.

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What is TNB doing to further reduce EMF emission?

We are taking all necessary measures to reduce EMF emission.
Amongst the steps taken are:

  1. Designing and configuring power lines and substations that minimize EMF emission.
  2. Providing extra precautionary measure by maintaining wider clearance than the statutory requirement.
  3. Complying with EMF regulations, guidelines or best practices recognized by international bodies.
  4. Prohibit development directly beneath TNB lines and within their right-of-way to ensure safety clearances.
  5. Review and update scientific findings on EMF across the world and continue to reassess any implications for the way in which we operate.

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