Quote Originally Posted by GCE View Post
The best earth is to place a piece of metal in water 40 to 100m under the ground, which will be the metal casing of the motor and pump.

Why run an inferior earth 40 to 100m down to the pump ?

To me you are now earthing the installation that you are taking the earth wire from to a perfect " earth spike" 40 to 100m down and always wet .
Whilst the SANAS regulations are aimed at personal safety with regards to electrocution, the earthing of the motor is to protect the motor, and electronic controls connected to the motor.
You will find more failures in applications in which the bore hole motor has not been earthed, as opposed to the ones that are.