"whisky-dave" wrote in message
...
On Monday, 12 August 2019 08:38:39 UTC+1, Jim GM4DHJ ... wrote:
just figured out what the two extra holes are just below the earth
terminal
of a double 13A socket I bought at a car boot sale ......

Usually it's the live and neutral ;-)

no...this is a single hole just under the earth above live and neutral
......well two of them