The NEC Ground Wire Size Chart provides guidelines for selecting the minimum size of equipment grounding conductors based on the phase and conductor size specified in American Wire Gauge (AWG) or kcmil units. This chart helps ensure electrical safety compliance by specifying appropriate grounding conductor sizes for single-phase and three-phase systems.
Chart Data
| Phase (Φ) | Conductor Size (AWG or kcmil) | Minimum Size of Equipment Grounding Conductors (AWG or kcmil) |
|---|---|---|
| Single Phase | 14 – 1 | 14 |
| 1/0 – 350 | 10 | |
| 400 – 1000 | 8 | |
| 3 Phase | 14 – 1 | 14 |
| 1/0 – 350 | 10 | |
| 400 – 1000 | 8 | |
| 1100 – 2000 | 6 | |
| 2500 – 4000 | 4 |
Conclusion
The NEC Ground Wire Size Chart provides guidelines for selecting the minimum size of equipment grounding conductors based on phase type and conductor size, with larger conductor sizes requiring correspondingly larger ground wire sizes for safety and compliance with electrical codes.
FAQ
What is the minimum size requirement for a NEC ground wire in a residential wiring system?
The NEC requires a minimum copper ground wire size of 10 AWG for a 100-amp service and 8 AWG for a 200-amp service in residential wiring systems.
Can I use aluminum wire as the ground wire in accordance with NEC guidelines?
No, the NEC prohibits the use of aluminum wire for grounding purposes in residential wiring systems. Only copper wire is allowed for grounding.
Do I need to install a separate ground wire for each individual circuit in a residential wiring system?
No, the NEC allows for a single grounding conductor to be installed and connected to grounding electrodes to provide grounding for the entire electrical system in a residential building.
What type of insulation is required for NEC ground wires?
The NEC requires ground wires to be insulated and color-coded with green insulation to distinguish them from hot and neutral wires in the electrical system.
Is it acceptable to use a smaller ground wire size than what is specified by the NEC?
No, it is essential to comply with the minimum ground wire size requirements specified by the NEC to ensure the safety and integrity of the electrical system. Using a smaller size may lead to increased risk of electrical hazards and is not recommended.