Grounding conductor

What is Grounding conductor ? What is the size of Grounding conductor ?

What is Grounding conductor ?

A ground conductor is defined as a wire or conductor connected to the earth. The grounding conductor is commonly known as a ground conductor

The ground wire is connected with a case or outer part of the electrical appliances, or tools.

So the grounding conductor is also known as case ground.

The grounding conductor is used for safety purposes. In normal conditions, the grounding wire does not carry current but when a fault occurs in a circuit or in any equipment. The grounding wire provides a low resistance path to the current and route the fault current to the earth.

Grounding conductor provides an alternate path to current under-fault conditions. So when fault occurs, the fault current will flow through a ground conductor instead of a human body or internal part of the equipment.

What is color of grounding conductor ?

This conductor does not require insulation. It can be installed as a bare conductor. And if the insulated wire is used as a ground conductor, the color of this conductor is “green”.

Green grounding conductor

Calculation of Grounding conductor ?

This conductor is used to provide a low-impedance path to the fault current under fault condition and it put electrical equipment to near-zero electrical voltage. And all fault current route to the earth.

The size of a conductor should not be less than 25% of the capacity of the phase conductor or over-current device.

According to NEC (National Electrical Code Academic and Science), a minimum size of a grounding conductor is decided as per the below table.

Rating or Setting of Automatic Overcurrent Device in Circuit Ahead of Equipment, Conduit, etc. Not Exceeding (Amperes) Copper (AWG) Aluminum (AWG)
60 10 8
100 8 6
200 6 4
300 4 2
400 3 1
500 2 1/0
600 1 2/0
800 1/0 3/0
1000 2/0 4/0
1200 3/0 250
1600 4/0 350
2000 250 400
2500 350 600
3000 400 600
4000 500 800
5000 700 1200
6000 800 1200

In Above table First column showing Current in circuit flows under fault condition.

And 2nd rows showing size of grounding conductor in AWG against the current showing in amp is same row when using of conductor of copper Metal.And 3rd rows showing size of grounding conductor in AWG against the current showing in amp is same row when using of conductor of Aluminium Metal.”AWG” stand for American wire gauges are a standard set of sizes for wire conductors — the smaller the wire gauge, the larger the diameter in inches or millimeters, and vice versa


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