My intention was a 6A feed off an existing 10A circuit, just to power a 60W light bulb and a single receptacle for maybe a table light or a 800W heater in the winter. The 16mm2 were for lightning protection.
The surge diverters weren't required, just strongly recommended. Hearing about the 16mm2 I nearly choked and had to strain hard not to call them crazy.
Besides, there's no way I could attach a 16mm2 wire to the equipotential bonding bus bar in the basement. All screws are rusted shut, except for the part of the bar that has already broken off from rust... [Linked Image]
According to new code we would have to drive a 30mm copper ground rod with a length of 4,5m(!).