Some codes require a grounding conductor to be buried approximately 3 feet (1m) outside and parallel to the fence. A grid system normally extends over the entire substation switchyard and often beyond the fence line. ![]() Ground rods should be placed at the grid corners and never less than 6 feet apart by design. At cross-connections, securely bond the conductors together by thermite welding, brazing, or approved compression connectors. 4/0 or 2/0 AWG bare copper conductors buried 18 inches (0.5 m) below grade, minimum, spaced 10 to 20 feet (3 to 6 m) apart, in a grid pattern. A typical grid system for a substation may include 70 or 120 square millimeters (mm2), No.Within the loop, the conductors lay in parallel lines and, where practical, along the structures or rows of equipment, to provide for short ground connections. ![]() Enclosing more area also reduces the resistance of the grounding grid. This practice helps to avoid high current concentration and hence high gradients both in the grid area and near the projecting cable ends.
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