Is there any way to measure the contact current?


EU guide - appendix 'B' - for the implementation of the EMF directive for example on the measurement of contact current.

Is the amount of "corona noise" and level of electric field related?


Yes. The air contains free electrons and ions under normal conditions. A strong electric field will create a force field that acts on free electrons and ions. The charged particles collide with each other. And we get corona.

Is there a high electric field where there is a lot of corona noise?



If one has an electric field of 20kV/m and has to stay there - is it possible to say how long the exposure time can be harmful to health?


The Norwegian authorities have chosen to follow the recommendations of ICNIRP, which is a health organization linked to the UN system.

See Appendix 5 to 7

A standard working day is 8 hours = "Occupational exposure". ICNIRP, the Norwegian Occupational Safety and Health Authority etc. say that when a worker moves out of the electric field (after the end of the working day), the body starts again the next day. There is thus no restriction on the number of days as long as you stay below the measure values.

Can you give some examples of protective measures where EMF has a limit value in the yellow and red category?



If the body (Torso) is exposed to electric fields of the order of 10-20 kV/m, the employee must receive training/information, and the employer must take measures against spark discharge and (continuous) contact current (must be less than 1 mA).


If the body is exposed to electric fields higher than the upper measure value (20 kV/m), measures must be taken. One measure is the use of Faraday clothing.

The answers have been prepared by customer advisor Rolf Kinck and senior instructor Rune Øverland.

Trond Løfquist

Sales contact - Trainor Elsikkerhet AS