I dont know why Iggy is talking about Lightening:
My On Site Guide says the earthing conductor need only be 2.5 mm-squared for TT if protected, I think that'd melt with lightening.

But 2.5 mm-squared does seem very thin compared to the new meter tails to the consumer units and earth wires i was sold with them. I dont understand why OSG Table 4.4.ii says only 2.5 mm-squared

I thought the earthing conductor is for use in case of an electrical fault, a loose live wire, earthing most of the current through copper not through me until a fuse blows or RCB trips.

There's an 80 or 100 amp main fuse isnt there,
which would be of no use for lightening.
Or would it?

[george]