What is the preferred size for ground rods used in manholes (MH)?

The preferred size for ground rods used in manholes is typically 10 3/4 inches. This size is chosen because it provides an adequate length for effective grounding, ensuring that the rod can penetrate the ground sufficiently to establish a low-resistance electrical connection. Ground rods play a critical role in safety and equipment protection by directing excess electrical energy away from sensitive infrastructure in the event of a surge or fault.

Using an appropriate length helps to ensure compliance with safety standards and codes that govern grounding practices. A 10 3/4 inch ground rod strikes a balance between effective performance and practical installation within a manhole, where space can be limited. It optimally contributes to minimizing the risk of electromagnetic interference and ensures proper function of electrical equipment, making it a reliable choice for grounding systems in this context.

In contrast, other sizes do not meet the optimal standards for grounding effectiveness or may not fit as well within the spatial constraints of a manhole, hence are less preferred.