Neutral and earth wires are often confused in the electrical trade. As both conductors are operating with zero voltage. When we connect the ground wire as a neutral wire by mistake, then the devices will operate correctly. But, such connections are against the code, because each conductor has different functions in electrical installations. This article will deal with the difference between earth and neutral. Understanding the difference between earth and neutral may be difficult in the beginning. Many safety and protection related aspects need to be carefully considered while understanding these concepts. Generally, the neutral point is earthed at the distribution transformer. It helps in keeping the earth and neutral in the same potential which protects the equipment against dangerous voltages in neutral.
What is Neutral?
The neutral wire acts as a return conductor for current flow in the electrical circuit. It completes the AC circuit. It carries the return current back to the source of electricity i.e. transformer. This point is earthed. Ideally, in an AC system, neutral and earth should be at the same potential.
It means the voltage measured between the neutral and the earth should be zero. This current can be primarily because of the phase current imbalance. The magnitude of this current is a fraction of phase current or in a few cases even double of the phase currents.
What is the Earth?
An Earth, also termed as ground, is a safety connection to protect the electrical appliances from the electric shock. When a bare conductor inside the equipment touches its metal body, then there is a risk of electric shock to the person who may be using it. This earth conductor provides a low resistance path for the leakage currents to be discharged.
Therefore, it protects the equipment and the person as well. Thus, it is useful for safety concerns against leakage or residual currents in the system. Phase and neutral are connected to the main power wiring, whereas the earth is connected to the body of the equipment. In case of insulation failure, this wire carries some minor current.
Difference Between Earth and Neutral
The important difference between earth and neutral
|Definition||It is the least resistance path, for giving safety against residual currents.||In the AC circuit carrying current in normal condition, it gives the return path and hence does the load balancing.|
|Current flow||In a normal situation, it doesn’t carry any current. But will have minor current in case of insulation failure.||A neutral wire is always charged with current.|
|Conversion||It cannot be turned into the neutral wire.||It can be turned into the earth wire.|
|Connection||It can come from the neutral line as well as may be separately executed.||It comes from the neutral line connection.|
|Role||It is the surging point for the appliances.||It is the return path for the supply of the current and termed as the reference point.|
Role of the neutral wire in electric circuits:
The need for a neutral conductor is for two important functions. One is for serving as a zero-voltage reference point and the second is for providing a return path for the current supplied by the live conductor. The only live conductor will not activate the circuit, because the current cannot circulate and hence no voltage difference will be applied. For a three-phase circuit, there may be cases where there is no need for the neutral conductor. Three-phase loads like electric motors run with three live conductors without any neutral conductor.
Role of the earth wire in electric circuits:
Earth wire is also having zero voltage similar to the neutral wire, but it accomplishes a very different role. It provides a grounded connection to all appliances and the equipment. Under the normal conditions, all current returns through the neutral wire and hence the grounding conductor will have no current.
On the other hand, when a line fault occurs, then the grounding conductor is giving an alternate path for the fault current. Meanwhile, electrical protections will detect such a situation, and as a result, will disconnect the circuit from the power supply. This ground fault may affect any circuit, so the grounding conductor is a must even when there is no neutral conductor.
FAQs about Earth and Neutral:
Q.1: Is there some voltage difference between neutral and earth wire or not?
Solution: Yes. Neutral to earth voltage is also termed as common-mode voltage.
Q.2: Why is the main’s neutral wire tied to the earth wire?
Solution: Reasons for grounding the neutral are as follows:
- Grounding the neutral wire is providing the common reference for all things plugged into the power system.
- Without the ground wire, static electricity will build-up to the point and hence may cause significant loss in transmitted power, overheating, fires, etc.
- It gives a return path to neutral, as a short path to the grounded chassis of an appliance will cause a predictable outcome in terms of a fuse.