The upper end of the ground rod must be flush with or underground unless the grounding electrode conductor attachment is protected against physical damage as specified in 250.10. See 250.52(A)(5) and 250.53(A) for additional details. When the grounding electrode attachment fitting is located underground, it must be listed for direct soil burial [250.68(a) Ex. 1, and 250.70].

Where more than one grounding electrode system exists at a building or structure, they must be separated by at least 6 feet.

Where within 18 inches of earth, the conductor used to bond grounding electrodes together to form the grounding electrode system must be copper [250.64(A)], securely fastened to the surface on which it's carried, and be protected if exposed to physical damage [250.64(B)]. The bonding jumper to each electrode must be sized in accordance with 250.66.

In addition, the grounding electrode bonding jumpers must terminate to the grounding electrode by exothermic welding, listed lugs, listed pressure connectors, listed clamps, or other listed means [250.8]. When the termination is encased in concrete or buried, the termination fittings must be listed and identified for this purpose [250.70].

The bonding connection to the interior metal water piping system, as required by 250.104(A), must not be dependent on water meters, filtering devices, or similar equipment likely to be disconnected for repairs or replacement. When necessary, a bonding jumper must be installed around insulated joints and equipment likely to be disconnected for repairs or replacement to assist in clearing and removing dangerous voltage on metal parts because of a ground fault. See 250.68(B) and 250.104 for additional details.

The underground metal water pipe grounding electrode, if present [250.52(A)(1)], must be supplemented by one of the following electrodes:

• Metal frame of the building or structure [250.52(A)(2)]
• Concrete-encased steel [250.52(A)(3)]
• Ground ring [250.52(A)(4)

• Ground rod in accordance with 250.56 [250.52(A)(5)
• Grounding plate [250.52(A)(6)]
• Metal underground systems [250.52(A)(7)]

• Grounding electrode conductor
• Grounded neutral service conductor
• Metal service raceway
• Service equipment enclosure

If working with a ground ring, it must encircle the building or structure, consist of at least 20 feet of bare copper conductor not smaller than 2 AWG, and be buried at a depth not less than 30 inches. See 250.52(A)(4) for additional details.

If working with a plate electrode, it must not have less than 2 square feet of surface exposed to exterior soils and installed so that it's at least 30 inches below the surface of the earth [250.52(A)(6)].