Slurp wrote:

"dennis@home" wrote in message
o.uk...

50/70 x 0.774 mOhms/m?

Nope, nothing like.
Its cross sectional area you need to use (pi * r^2)

No, the figures mentioned were clearly conductor CSAs in mm^2, so the
answer was right, at least for DC.

An easier way would to use the tabulated values for 35mm^2 and halve
them, giving 0.524 mohm/m for R1+R2 for 70+70 mm^2.

However the OP should be aware that for these large sizes used on AC the
impedance will be higher then the DC resistance because (a) skin
effect increases the resistance and (b) the inductive reactance is not
necessarily negligible. The OSG is only relevant to installation work
up to 100 A per phase, in which you would not usually need to use 70
mm^2 conductors!

--
Andy