electrical earth sheathing

[xraanswerban]

Hello there, why is there different sizes of green and yellow earth sheathing, does it matter if a larger sheathing is used, and also is it best to cover the earth wires individually or 2/3 earths together.

[AlBags]

To cater for overall total cable sq area.
Just cover each one and connect to earth point. Flexible tails help a lot here.