Nec Ground Wire Size Chart

The NEC Ground Wire Size Chart provides the recommended size of grounding conductors in relation to circuit conductor sizes in the AWG/kcmil format.
Circuit Conductor Size (AWG/kcmil) Grounding Conductor Size (AWG/kcmil)
14 14
12 12
10 10
8 10
6 10
4 8
3 8
2 8
1 6
1/0 6
2/0 6
3/0 4
4/0 4
250 kcmil 2
300 kcmil 2
350 kcmil 1
400 kcmil 1
500 kcmil 1/0
600 kcmil 1/0
700 kcmil 2/0
750 kcmil 2/0
800 kcmil 3/0
900 kcmil 3/0
1000 kcmil 4/0
1250 kcmil 250 kcmil
1500 kcmil 250 kcmil
1750 kcmil 250 kcmil
2000 kcmil 250 kcmil

The NEC Ground Wire Size Chart provides information on the appropriate grounding conductor size for different circuit conductor sizes, as specified by the National Electrical Code (NEC). This chart ensures compliance with safety standards and helps electricians and engineers determine the correct grounding wire size for electrical installations. The chart lists the circuit conductor size in AWG (American Wire Gauge) or kcmil (thousand circular mils) and the corresponding grounding conductor size. It serves as a valuable reference tool for designing and implementing electrical systems to maintain proper electrical grounding.


What is a NEC ground wire size chart?

A NEC ground wire size chart is a reference tool provided by the National Electrical Code (NEC) that helps determine the appropriate size of grounding conductors based on factors such as conductor material, circuit size, and type of grounding system.

Why is it important to use a NEC ground wire size chart?

It is important to use a NEC ground wire size chart to ensure that the grounding conductors used in electrical installations are sized correctly. Properly sized grounding conductors help maintain safe and reliable electrical systems by providing effective fault current paths and reducing the risk of electrical shocks, fires, or other hazardous conditions.

How do I find the NEC ground wire size chart?

The NEC ground wire size chart can be found in the National Electrical Code book itself, specifically in Table 250.122. This table provides recommended minimum sizes for grounding conductors based on the type and rating of the circuit, as well as the type of grounding electrode system being used.

What factors should be considered when using the NEC ground wire size chart?

When using the NEC ground wire size chart, it is important to consider the type of conductor material (e.g., copper, aluminum), the size of the electrical circuit, the type of grounding system being utilized (e.g., rod, plate, water pipe), and any derating requirements based on ambient temperature or conductor bundling.

Are there any exceptions or additional requirements to be aware of when using the NEC ground wire size chart?

Yes, there may be additional requirements or exceptions to consider when using the NEC ground wire size chart. These can include specific rules for certain types of installations, such as those involving transformers, services, equipment grounding conductors, or conductors used in hazardous locations. It is important to consult the NEC and any additional local or regional electrical codes for complete guidance.

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