Robert Maynard
Volunteer Moderator
If you've added an extension that has it's own earthing point, then that might cause problems with the powerline.
I can't really tell for sure though - it's been many, many years since I've dealt with ring circuits, and powerline Ethernet wasn't even a glint in the milkmans eye back then![]()
Fairly sure that the extension earths back through the original consumer unit - it had spare breaker slots.