Generally, load wires (also called downstream or outgoing wires) are connected to the top half of the switch box. Load wires connect the switch to a load or loads in an electrical circuit such as a bulb. The line and load wires are critical components in a circuit. Most people cannot tell these wires apart.
How can you tell apart a load wire in a circuit? In this guide, I will provide tips that will help you quickly identify a load wire in your electrical light fixture or any other electrical device. It is imperative to know the color codes of electrical wire.
Conventionally, load wires are black or red. And they are located on the top part of a switch. To identify a load or downstream wire, trace the black wire on top of your switch. These wires (load) deliver power to a device from a source.
Electrical Wire Color Codes
As aforementioned, electrical color code literacy is necessary whenever dealing with electricity. In this section, I will expose you to the colors used to denote wires such as live, line, ground, load, etcetera of electrical circuits. (1)
- Black Wires. All black wires are always considered live, and extra caution should be taken when dealing with them. These types of wires transfer current/power to the outlets and switches in a circuit.
- Red Wires. These are the secondary live wires, and they are also used in some switch legs. They are usually used in ceiling fan installations.
- Blue and Yellow wires. These types of wire labels act as live wires which are pulled through a conduit. In some applications, yellow wires serve as the switch legs in structural lighting and ceilings. The blue wires are widely used in 3 and 4-way switches. A good example is staircase switches where the top and the bottom switches can be used to control the same light bulb.
- Green wires ground the electrical circuits. They are linked to a grounding terminal in the outlet strongbox. Ideally, ground wires dissipate electrical current in the ground whenever the live wire touches a conducting material. Copper wires can also be used as ground wires.
- White and Grey wires are neutral. Neutral wires are assumed to be carrying no current. However, if the current load in a circuit I unbalanced, it may induce electrical current to the neutral wire. Always handle them carefully. The neutral wires are connected to conductive metals in an electrical panel causing the distribution of electrical current in the house. (2)
Load and Line Wires, What is the Difference?
The load wires link the light fixture to the light switch. On closing the switch, the load wires convey the electrical current to the lighting fixtures.
To avoid confusing the load wires with the line wires, not always look at the conventional colors of each wire. Load wires are usually black or red though. Important thing is that the downstream (or load) wires are at the top of the switch, whereas the line wires are located deep in the switch (about halfway inside).
Take a look at some of our related articles below.
- How to wire lights on a 48-volt golf cart
- How to use a multimeter to test voltage of live wires
- How to cap off electrical wires
(1) literacy – https://www.edutopia.org/blog/literacy-instruction-across-curriculum-importance
(2) metals – https://www.thoughtco.com/metals-list-606655