For clay soils, one ground rod is often used. Ground rods are driven 10' deep and placed at least 2' from the foundation wall. In shallow topsoil, grounding can be achieved by stranding the conductor and burying it in a long trench or attaching it to a copper ground plate. Materials and Installation Materials used in lightning protection systems must resist corrosion. Copper and aluminum cable are the most common, while copper alloys and copper-clad steel are also approved materials.
Aluminum conductors corrode when in contact with earth.
In other situations, combinations of materials subject to electrolytic action should be avoided. Proper installation is also critical, and should be done only by a qualified expert. Before you select an installer, check references and verify the installer's experience level with similar projects. Your insurance company may be able to recommend a qualified installer. To obtain approval from the Underwriters Laboratories Inc. for a Master Label, a special application form must be signed by the owner, the installer and the equipment manufacturer.