NEC Table 250.122: Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment

The minimum required size of an Equipment Grounding Conductor (EGC) should not be less than 14 AWG copper or 12 AWG aluminum / copper-clade aluminum. NEC 250.122. The size of EGC does not need to be larger than the largest ungrounded conductor in a circuit.

This section outlines the minimum size requirements for equipment grounding conductors based on the rating of the automatic overcurrent device. A table provides specific sizes for copper and aluminum conductors across various amperage ratings, ranging from 15 to 6000 amperes.

EGCs must be sized not smaller than shown in Table 250.122; however, the EGC is not required to be larger than the phase conductors [250.122 (A)]. Figure 01. Phase conductors are sometimes increased in size to accommodate conductor voltage drop, short-circuit rating, or future capacity.

Calculate the size of ground wire for a given circuit or motor by selecting the ampere rating of the circuit protection device.

Mar 2, 2021 · If you turn to Section 250.122 in the 2020 NEC, you find information that has been helping electricians to size equipment grounding conductors (EGC) for longer than most electricians have been pulling wire.

Sep 3, 2023 · Figure 1 shows two equipment grounding conductors (EGC) sized per the ampere rating or setting of the overcurrent device ahead of the raceway or equipment. Size EGC1 per CB1 and EGC2 per CB2, using Table 250.122 in both cases.

Feb 15, 2023 · The minimum size wire-type EGC for a 400A feeder is normally a 3 AWG copper, according to Table 250.122. The circular mil value of a 3 AWG conductor is 52,620 circular mils, as provided in NEC Table 8, Chapter 9.

Equipment Grounding Conductor NEC 250-122 . Table 250.122 Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment Rating or Setting of Automatic Overcurrent Device in Circuit Ahead of Equipment, Conduit, etc.,

The National Electric Code (NEC), specifically NEC 250.122, provides essential guidelines for determining the proper size of equipment grounding conductors (EGC) in electrical installations.