Memo 13/08: Electrical incident - Schuko plugs and adaptors

Colleagues at another university have alerted us to an electric shock incident involving a new item of Class I electrical equipment, a –70C freezer.  The freezer was supplied by the manufacturers with a Schuko CEE 7/4 (“Type F”) 2-pin plug1 and a BS 5733 Power Connections adaptor to allow it to be used in a UK 3-pin socket.

The Schuko plug was fitted into the adaptor the wrong way round, reversing the supply polarity to the freezer.  There was also an incomplete earth connection in the adaptor.  This resulted in a live metal casing on the freezer and an injury to the person who touched it.

Departments should be cautious if they buy imported electrical equipment that is not fitted with a UK 13 amp plug.  PAT testing such equipment before use would identify the problem described above.  Replacing the supplied plug and adaptor with a rewireable 13 amp plug would also be a sensible approach, although checks with suppliers may be needed to ensure this does not invalidate any warranty.

1 http://en.wikipedia.org/wiki/Schuko

August 2008