Line Versus Load Wire


Electricity is a crucial component of our day-to-day lives. The wiring systems play a vital role in delivering power to our homes and businesses. In electrical wiring, there are two primary types of wires known as the line wire and load wire. These wires serve different purposes and have distinct functions.

To have a better understanding of electrical wiring, we need to understand the differences between the line and load wire.

Line Wire:

The line wire is the first wire that connects to a power source such as an electrical panel, switch or outlet. It is also known as the hot wire, which carries voltage or electrical power through a circuit. The line wire connects to the power source through the electrical panel, and it can be identified by its color. In most houses, line wires are black or red. However, in some cases, they can be blue or yellow, depending on the country or region.

The line wire is responsible for delivering electrical power to electrical devices or lighting systems, and it should always be connected to the appropriate device or appliance. The voltage carried by the line wire can vary depending on the device connected to it, i.e., a 120-volt appliance will require a 120-volt line wire.

Load Wire:

The load wire connects to the electrical device that needs electrical power such as a light fixture or a home appliance. They are also called neutral wires, and they carry no voltage, but they act as a return path for the electrical current from the device back to the electrical panel. The load wire is essential as it provides grounding for the device, preventing electrical shocks.

The load wire is also coded for its color in most cases. It is white or grey, and it should also have marking tape to indicate that it is indeed neutral. In some cases, the load wire can be black or red, which can cause confusion, especially when doing electrical work.

To better understand line versus load wire, let’s consider the scenario of a light fixture installation. The wire that feeds the light fixture is the line wire, while the wire that connects the light fixture is the load wire. The line wire connects to the switch or electrical panel, and it provides and sends electrical power to the load wire that powers the light fixture.

Line versus Load Wire:

The fundamental difference between line and load wires is that the line wire carries the electrical power to the device, while the load wire sends the power back to the electrical panel. Line wires are the first wires to be installed, while load wires come last.

Another significant difference is that the line wire is the wire that carries voltage in the circuit, while the load wire is the wire that carries current. This explains why line wires are often black or red, while load wires are white or grey.

One of the most common mistakes when dealing with line versus load wires is mixing them up. When installing electrical switches or outlets, switching the line wire and the load wire can cause devices not to function correctly or create a short circuit, causing electrical shock or even fire.


1. What is the color code for line and load wires?

The line wire is often black or red, while the load wire is typically white or grey.

2. What happens when line and load wires are reversed?

When line and load wires are reversed, appliances or devices may not work correctly, or electrical shock hazards may occur.

3. Can line wires carry neutral currents?

No, line wires carry voltage, while neutral wires carry no electrical power.

4. Can load wires carry voltage?

No, load wires carry current, but they are not meant to carry voltage.

5. Can the same wire be used for both line and load wires?

No, line and load wires serve different functions, and using the wrong wire can cause electrical hazards.


Understanding the differences between line and load wires is crucial in electrical wiring. Proper installation and labeling of these wires can prevent electrical hazards, fires, and damage to devices. Always ensure that you use the appropriate wires for the right purposes and avoid mixing them up. Electrical work can be dangerous, so it is best to seek the help of a professional if you are not sure of what you are doing.