Earth is an important part of your electrical system, you need to have an earth for safety.  In audio equipment you will usually encounter problems if there is no earth stake.

Your electrician will be able to site visit and determine the cable required and this should always be an electricians job to spec.

Kit with:

Electrolyte copper bond earth rod. Non expandable.
Brass. Rod to lug earth clamp.

NOTE - All earthing rods should ideally have this tag - 'Safety electrical connection - dont not remove'