Number of Plates Required for Electrical Installation

Follow local electrical codes. In the UK, it is British Standard 7671.

Requirements vary from country to country. You must refer to your local electrical standards and regulations specific to your application for the answers.

Electrical earthing require the minimum earth Ohmic value less than 10 Ohm or some other country regulation require less than 6 Ohm. Normal earthing electrode will able to get the job done, of course, it also depend upon the soil that you have.

If your earthing electrode can not get less than the requirement of 10 Ohm or 6 Ohm, you can add another electrode to deepen it. Other method is to dig a hole and fill it up with coke or some carbon base material for the better conductivity of the earthing.

Mostly, we do not use copper plate for earthing unless it is for very special earthing for some electronic panel.