![]() ![]() Additional #2 tails are pulled to bond additional building components. A buried 4/0 ground ring with three grounding electrode conductors exothermically welded and pulled inside the building. Specified in table 250.122 the EGC connects individual loads back to the equipment ground bar in a panelboard, motor control center, etc. It’s important to understand the difference between the grounding electrode conductor and an equipment grounding conductor (EGC). ![]() The values listed in table 250.66 are therefore minimums. In the event of a phase-to-ground fault the GEC must be large enough to survive for the power system’s protection to operate and clear the fault. ![]() The larger the ungrounded conductors, the larger the GEC. Building steel and metal underground water piping that qualifies as a grounding electrode may require a larger GEC since the GEC to these electrodes is sized based on the size of the service entrance conductors and Table 250.66. Sizing the GEC is correlated to the size of the ungrounded (current carrying) conductors. The minimum size GEC permitted to connect a concrete encased electrode is 4 AWG copper. The size of the equipment grounding wire for the PV source circuits. For example, in a panelboard the GEC connects the neutral bus bar to the buried ground rods, ground ring, building steel, concrete encased Ufer etc. Grounding electrode conductor: Bare copper wire connecting grounded conductor. The grounding electrode conductor (GEC) connects an electrical system’s grounded conductor to the grounding electrode system (GES). Where there are no service-entrance conductors, the grounding electrode conductor size shall be determined by the equivalent size of the largest service-entrance conductor required for the load to be served.ĪThis table also applies to the derived conductors of separately derived ac systems.īSee installation restrictions in 250.64(A).If multiple sets of service-entrance conductors connect directly to a service drop, set of overhead service conductors, set of underground service conductors, or service lateral, the equivalent size of the largest service-entrance conductor shall be determined by the largest sum of the areas of the corresponding conductors of each set.Size of Grounding Electrode Conductor (AWG/kcmil) Some of those are: Copper, aluminum, or copper-clad aluminum conductors Rigid metal conduit (RMC) Intermediate metal conduit (IMC) Electrical metallic tubing (EMT) Frequently, EGCs are the raceway system, RMC, IMC, or EMT. NEC Table 250.66 Size of Largest Ungrounded Conductor or Equivalent Area for Parallel Conductors (AWG/kcmil) EGCs come in various sizes, types, and materials as found in the 2020 NEC, Section 250.118. ![]()
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