For services over 100 amperes, which grounding electrode conductor material is most commonly used?

For services over 100 amperes, copper is the most commonly used material for grounding electrode conductors due to several key properties. Copper offers excellent electrical conductivity, which is crucial for grounding applications. It ensures that any fault current can be quickly and efficiently conducted to the ground, reducing the risk of electrical shock and improving safety.

Additionally, copper is highly resistant to corrosion, allowing it to maintain its conductive properties over time, even in harsh environmental conditions, which enhances the reliability of the grounding system. Copper's strength and ductility allow it to be easily formed and installed, adapting well to various installation environments.

While aluminum is also used in some applications, it does not match the conductivity and corrosion resistance of copper, making it less favorable for grounding electrodes in scenarios involving higher current loads. Steel and tin are not commonly used for grounding conductors due to their inferior conductive properties and potential for corrosion, which can compromise their effectiveness as grounding materials. Thus, copper is the preferred choice for grounding electrode conductors in higher-amperage services.