I have two related questions about the earth conductor in household
wiring.

1) in my 1960s house, most of the ring main has multistrand earth
conductor; it looks as if it has the same x-sectional area as the L
and N. However, one part (added later) uses cable with only a single
strand earth. the L and N seem to be the same area (2.5 sqmm).

If a house uses a mixtrure of earth sizes does this not mess up a ring
conductivity test? The expected earth resistance cannot be calculated
properly so how can it be checked?

2) The cooker to wall outlet uses a 6 sqmm cable. the L and N are
multistrand but the earth is a single strand. The cable came from
Homebase and was sold for the purpose. Surely in an appliance cable
should have multistrand earth to avoid fractures due to repeated
flexing. the cooker is regularly pulled out for cleaning etc.

Nobody seems to sell 6sqmm cable designed for flexing (currys comet
homebase bnQ). is it really normal to use "single strand earth" cable
for a cooker?

thanks for any comments anyone cares to make.

Robert