Why neutral wire has no current?

Answered by Phillip Nicastro

Well, let me start by saying that the concept of the neutral wire having no current can be a bit confusing, but I’ll do my best to explain it in a clear and detailed way.

In an electrical circuit, current flows due to the movement of charged particles, typically electrons. The flow of current is always from a higher voltage point to a lower voltage point. When we talk about the voltage at a specific point, such as the neutral wire, we are actually referring to the voltage difference between that point and another reference point, usually called “ground”.

Now, in the context of the electric power grid, the neutral wire is connected to the earth or ground, and this is by definition considered to be at zero voltage. This means that the voltage difference between the neutral wire and ground is always zero, and therefore the voltage of the neutral wire is also considered to be zero.

But what about current? Well, in a typical residential or commercial electrical system, the neutral wire is connected to the center tap of the transformer on the utility pole. This center tap is connected to the earth or ground, creating a reference point for the entire electrical system.

When electrical devices are connected to the power grid, they create a closed loop circuit where current can flow. The current flows from the hot wire, which has a higher voltage, through the electrical device, and then returns through the neutral wire back to the transformer. This completes the circuit and allows the flow of electrical energy.

However, since the neutral wire is connected to ground, it provides a path for any excess current to flow directly into the ground. This is an important safety feature because it helps prevent the buildup of excess voltage and reduces the risk of electrical shock or damage to appliances.

So, while the neutral wire does carry current, it is always designed to carry the return current from the electrical devices back to the transformer, and its voltage is always considered to be zero relative to ground. This is why we say that the voltage of the neutral wire is zero, even though it does carry current.

To summarize, the neutral wire in the electric power grid is connected to ground and serves as a reference point for the entire electrical system. Its voltage is always considered to be zero relative to ground, but it does carry current as it provides a return path for the electrical current from the devices back to the transformer.