On 14/02/2020 11:06, Tim Watts wrote:
On 13/02/2020 22:35, TimW wrote:

Earth rod and required RCD measures if you are a TT installation.


But are you maybe a TN-C-S or TN-S (supplier provided earth) and this
clamp was merely equipotential bonding?


Going to add - if you can't work it out, best call a local sparky around
asap to check it out. The worst case scenario as others have mentioned
is a very dangerous installation.