Figure 2-3. Aluminum conductors
b. The size of the conductor used between the power panel and the grounding rod is determined
by the ampacity of the system being grounded. For a 100-ampere service, the ground conductor must be
No. 8 copper or No. 6 aluminum (Figure 2-4).
Figure 2-4. Size of conductor
c. When the grounding electrode is a high-capacity grounding system, such as metallic water or
piping systems with at least 10 feet of underground pipe in contact with the soil, the system (metallic or
piping) must be used as indicated in Table 2-1, page 2-4.
d. Metallic water pipe that has 10 feet or more of its length in direct contact with soil must be
bonded into the grounding system (Figure 2-5, page 2-4).