Richard started by detailing the various systems of mains connections to private properties. Houses built from about 1970 are likely to be configured as PME: Protective Multiple Earth.  For most houses this is sufficiently safe.  However, radio amateurs face a possible catastrophic failure if there is a break in the protective multiple earth lead (possibly cause by nearby construction work etc.) and their station is conneted to an RF earth that becomes the earth for the PME system.  These breaks have  been reported about 400 times in the past year. Richard outlined what radio amateurs with the PME setup should be doing about the perceived need for an RF earth connection: Don’t do it!   Richard’s full presentation can be read  at our website under the tab ‘Practical Stuff’  titled ‘Earthing and RF’