If the subpanel is installed on the same premises, you only need one ground rod with a properly sized grounding conductor, as specified in NEC Table 250. An additional ground rod is required if the subpanel is located in a separate building. Related Posts:A sub panel is a secondary distribution point that receives power from the main service panel, allowing for the extension of electrical service to a remote area of a building or a separate structure like a garage or shed. Proper grounding and bonding of this secondary panel are necessary safety. Secondary equipment grounding refers to connecting the secondary equipment (such as relay protection and computer monitoring systems) in power plants and substations to the earth via dedicated conductors. The neutral conductor is typically the grounded conductor connected to the system's neutral point, carrying current under normal operation. The grounding electrode conductor connection to. secondary unit substation is a close-coupled assembly consisting of enclosed primary high voltage equipment, three-phase power transformers, and enclosed secondary low-voltage equipment. Two or more grounding electrodes that are.