The NEC ground wire size chart defines the least instrument grounding conductor size for single and 3 phase systems according to conductor size for ranges such as 14 AWG to 4000 kcmil. Here we will cover details for the ground size chart and other features. So let’s get started with What Size Ground Wire Do You Need?
What section of the NEC covers grounding?
NEC code provides the details of the ground wire in Article 250 Table 250.66. 250.66 NEC table also called equipment grounding conductor size chart.
Copper Ground Wire Size Chart
| Size Of Copper Wire AWG or KCMill | Copper Grounding Electrode Conductor Size (AWG or kcmil): | Amps |
| 8 AWG | 8 AWG | 50 Amps |
| 6 AWG | 8 AWG | 65 Amps |
| 4 AWG | 8 AWG | 85 Amps |
| 3 AWG | 8 AWG | 100 Amps |
| 2 AWG | 8 AWG | 115 Amps |
| 1 AWG | 6 AWG | 130 Amps |
| 0 (1/0) AWG | 6 AWG | 150 Amps |
| 00 (2/0) AWG | 4 AWG | 175 Amps |
| 000 (3/0) AWG | 4 AWG | 200 Amps |
| 0000 (4/0) AWG | 2 AWG | 230 Amps |
| 250 kcmil | 2 AWG | 255 Amps |
| 300 kcmil | 2 AWG | 285 Amps |
| 350 kcmil | 2 AWG | 310 Amps |
| 400 kcmil | 0 (1/0) AWG | 335 Amps |
| 500 kcmil | 0 (1/0) AWG | 380 Amps |
| 600 kcmil | 0 (1/0) AWG | 420 Amps |
| 700 kcmil | 00 (2/0) AWG | 460 Amps |
| 750 kcmil | 00 (2/0) AWG | 475 Amps |
| 800 kcmil | 00 (2/0) AWG | 490 Amps |
| 900 kcmil | 00 (2/0) AWG | 520 Amps |
| 1000 kcmil | 00 (2/0) AWG | 545 Amps |
| 1250 kcmil | 000 (3/0) AWG | 590 Amps |
| 1500 kcmil | 000 (3/0) AWG | 625 Amps |
| 1750 kcmil | 000 (3/0) AWG | 650 Amps |
| 2000 kcmil | 000 (3/0) AWG | 665 Amps |
Grounding Requirements in Solar Design
Understanding the NEC’s Role:
The NEC is a commonly used standard for electrical installations and offers details and rules that are important for ensuring the safety and operation of solder energy systems. For solar design, NEC Article 690 is used to define the installation and grounding of solar photovoltaic (PV) systems.
 Grounding Electrode Systems (690.41):
NEC explains the creation of a grounding electrode system for solar connections. it comes with proper bonding with the ground, normally through grounding electrodes such as ground rods. Accurate configuration and bonding of electrodes are important for offering a proper path for fault currents to dissipate to the ground
 Equipment Grounding (690.43):
The main solar equipment is PV modules and inverters should be grounded to avoid shock hazard. The NEC 690.43 defines features for instrument grounding, focuses on accurate bonding for controlling the chances of shock and ensures longevity of the solar components.
Ground-Fault Protection (690.5):
Detection and solving the grounding error are the main factors for solar systems. NEC 690.5 defines the system for ground fault protection in solar connections. it comes with system implementation and devices that can find and solve ground faults and reduce the chances of electrical hazards.
 Grounding of DC and AC Systems (690.47, 690.48):
NEC Article 690 also defines the grounding of DC and AC system in solar systems. Accurate grounding of conductors and instruments for both systems is important to a safe and reliable solar energy system.
What size ground wire do I need for a 3 AWG wire?
The 3 AWG comes with an ampacity of 100A for a median 75C (167°C) temperature. So people think more about 100 amp wire.
For defining the size of the ground wire get details for the copper grounding size chart, and check that there is a need 8 AWG copper ground wire for 3 AWG copper wire.
There is nothing wrong if applying 6 AWG or 4 AWG ground wire and it will perform the same work.
What size ground wire do I need for 250 kcmil wire?
250 kcmil copper wire comes with 255A ampacity at median conductor temperature. if you use NEC 80 percent rule, 250 Kcmil has features to handle about 24 amps.
On the above charge for copper ground wire size, there is need 2 AWG copper ground wires for handling 250 kcmil wire.
So there is need of 2AWG copper ground wire for 200 Amp service.
Aluminum Ground Wire Size Chart
| Size Of Aluminum Wire (AWG or kcmil): | Aluminum Grounding Conductor Size (AWG or kcmil): | Amps: |
| 6 AWG | 6 AWG | 60 Amps |
| 4 AWG | 6 AWG | 75 Amps |
| 3 AWG | 6 AWG | 85 Amps |
| 2 AWG | 6 AWG | 100 Amps |
| 1 AWG | 4 AWG | 115 Amps |
| 0 (1/0) | 4 AWG | 135 Amps |
| 00 (2/0) | 2 AWG | 150 Amps |
| 000 (3/0) | 2 AWG | 175 Amps |
| 0000 (4/0) | 0 (1/0) | 205 Amps |
| 250 kcmil | 0 (1/0) | 230 Amps |
| 300 kcmil | 0 (1/0) | 255 Amps |
| 350 kcmil | 0 (1/0) | 280 Amps |
| 400 kcmil | 000 (3/0) AWG | 305 Amps |
| 500 kcmil | 000 (3/0) AWG | 350 Amps |
| 600 kcmil | 000 (3/0) AWG | 385 Amps |
| 700 kcmil | 0000 (4/0) AWG | 420 Amps |
| 750 kcmil | 0000 (4/0) AWG | 435 Amps |
| 800 kcmil | 0000 (4/0) AWG | 450 Amps |
| 900 kcmil | 0000 (4/0) AWG | 480 Amps |
| 1000 kcmil | 0000 (4/0) AWG | 500 Amps |
| 1250 kcmil | 250 kcmil Aluminum Ground Wire | 545 Amps |
| 1500 kcmil | 250 kcmil Aluminum Ground Wire | 585 Amps |
| 1750 kcmil | 250 kcmil Aluminum Ground Wire | 615 Amps |
| 2000 kcmil | 250 kcmil Aluminum Ground Wire | 630 Amps |
How big aluminum ground wire do you need for a 00 AWG aluminum wire?
In the aluminum ground wire size table you can see that 2 AWG aluminum ground wire for 00 AWG aluminum wire grounding.
What size ground wire do I need for 500 kcmil aluminum wire?
In NEC equipment grounding conductor chart for aluminum wires and check that there is 000 AWG aluminum ground wire used for adequately grounding a 500 kcmil aluminum wire.
Read also:
- What Size of Wire Do I Need for a 100 Amp Sub Panel?
- 60 Amp Wire Size – Which AWG is Best for 60 Amp Breaker
- What size wire to carry 40 amps?
- WHICH SIZE WIRE IS USED FOR ELECTRIC DRYERS?
- How to feed wire to a 400 Amp meter base?
Faqs
What size should ground wire be?
- The rule of sizing ground wires in an electrical circuit is to use same size as hot and neutral wires, or use larger sizes if the circuit breaker or fuse is larger than 60 amps. It ensures accurate protection from electrical hazards and also saves equipment damage
What is the standard for ground wire?
- Ground wire also defined as grounding electrode conductor, is a connection between ground rod and service ground connection. Ground wires for commercial buildings are made with copper #6 (6 AWG) or larger. For 200 Amp services, a #4Â (ground wire) is required
What size ground wire for 60 amps?
- There is 10 AWG ground wire used for 60 amps. The ground can be solid bare or insulated. Stranded wire easy to operate so use insulated green stranded.
Which size of wire is used for earthing?
- The size of the earth wire is defined through the amperes capacity of service wires. The minimum wire size for earth for light circuits is  1 mm square for copper and 1.5 mm square for aluminum.
How do you measure ground wire?
- Set the multimeter at continuity or resistance setting. Connect one-meter lead with ground wire and another probe with a known ground metallic water pipe. If the meter gives sound or has less resistance value, the ground wire is accurately connected
How many amps is a ground wire?
- There is zero amps on the ground wire. On 230 volts devices, the neutral wire does not carry any amps, with control or some 110V component such as the control panel. Mostly white wire is used for 2nd hot leg rather than neutral.
What size ground for 100 amps?
- The ground wire size for 100 amp is different. Use 8 AWG copper grounding wire or 6 AWG aluminum grounding wire
How do I choose ground wire size?
- It is mainly used that normal work to choose the size of grounding conductor with a current capacity not less than 25% of the capacity of the phase conductor or overcurrent device
