Microshocks

In certain circumstances, a person exposed to a high electric field could experience small spark discharges on touching other objects, producing a prickling sensation similar to that caused by the static discharges commonly experienced in dry atmospheric conditions after frictional contact with a nylon carpet or car seat. Normally, any sensation is confined to the momentary spark discharge as contact is made or broken. The current NRPB exposure guidelines say:

"In many exposure conditions and for most people, the annoying effects caused by electric charge on the surface of the body will not occur at power-frequency electric field strengths below 12 kV/m."

The 2004 NRPB advice on limiting exposures says:

“When and ungrounded person is in an electric field and comes into contact with a grounded object there is the possibility of occurrence of a spark discharge at the point of contact between the person and the object. For fields external to the body greater than about 5 kV m^-1, there is the likelihood of such discharges being painful. The extent to which this is a problem in practice is unclear and further investigation is merited.

“When a person is in an electric field and comes into contact with an ungrounded object there is the possibility of occurrence of a spark discharge at the point of contact between the object and the person. For such situations, the probability and the magnitude of the effect depend on the field strength and the size of the ungrounded object.”

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