There are reports that a prominent News personality in the United States is being sued by a person who was injured by an electric fence. He was working on the property rewiring a television cable from the street to the home and got locked into the property by an automatic gate that he was unable to open to go to collect additional tools required. He decided to climb over the fence and got shocked whilst doing so.

He was "thrown to the ground" by the shock and sustained injuries for which he is seeking compensation.

For him to be "thrown to the ground" the energiser in use would have to be one with a high joule rating - possibly in excess of 20 joules. These high rated energisers push out a substantial amount of energy especially when used on short fences for security purposes. These are commonly available in America and Australia where considerable distances are covered by a single energiser and should not be employed on short fences. Whether he was using a common electric fence tape or not is not know. 

It was for this safety reason that the European Union instituted legislation restricting the size of energisers onto the market to a maximum continuous output of 6 joules. This blog post outlines the European standards.

This does not necessarily restrict the manufacturer to 6  joules providing the energisers' circuitry prevents the continuous output of 6 joules. There is the HoriSmart range of electric fence energisers that are able to recognise what sort of contact is being applied to the fence and so deals with it accordingly