To ensure that employees are working safely and keeping up with the latest electrical codes, it is important that they follow well-established wire color codes. These are designed to help prevent people from accidentally getting injured while handling dangerous equipment.
In most facilities, electricity is brought in at one point and then distributed to various parts of the building through a series of wires. While it is not always thought about, electricity can cause various issues and even impede work if it is not properly managed. This is why it is important that employees follow proper wire color codes.
The Different Types of Wire Color Codes
There are various types of wire color codes that are used in different countries. They can be used depending on the type of electricity that is being used, as well as other factors such as the cables and circuits.
Understanding the various options that can be used in an electrical situation is very important for workplace safety.
Wire Marking Colors for DC Power
DC power is a type of electrical device that operates in a straight line. Unlike traditional AC power, which can travel long distances, DC power can only run in a straight line. This type of power is commonly used in various types of equipment such as batteries and solar cells.
There will typically be two or three wires when wiring for DC power. The colors are as follows:
- Red must be the positive current.
- The negative current must be completely black.
- If a ground wire is used, it must be white or grey.
Wire Colors for AC Power
In the US, alternating current, or AC power, is commonly used in standard home and business electrical outlets. This type of power is unique because it can change the direction of its flow of charge.
An AC wave is generated by the current of the device, and it can move in a sinusoidal manner, which allows it to move further than DC power.
AC power comes in various types depending on the amount of volts it will be carrying. This type of wiring has multiple phases that each have their own color wire. These wires are designed to make it easier for people to identify what they are working on.
The wiring color standards listed below are used for wires that will be 120, 208, or 240 volts.
- The wiring in phase 1 should be black.
- The wiring in phase 2 should be red.
- The wiring in phase 3 should be blue.
- The neutral wire should be white.
- Green or green with a yellow stripe may be used for ground wiring.
Sometimes, there will be a higher-leg connection that carries a higher voltage than the other wires. These types of connections are called high-leg connections. To identify these types of wires, look for one with an orange-colored wire.
High-Voltage Wire Color Code
These types of connections are commonly used in industrial areas and are known to have serious safety issues. Getting the correct color codes is important to ensure that the wires are working properly.
The following wiring color standards are used for wires that will be 277 or 480 volts.
- The wiring in phase 1 should be brown.
- The wiring in phase 2 should be orange.
- The wiring in phase 3 should be yellow.
- Grey should be used for neutral wires.
- Green or green with a yellow stripe should be used for ground wiring.
These are the standards that are used in the US when it comes to wiring. In other countries, such as Europe, there are different standards. This means that certain types of machinery made in the US will need to follow the US’ wire color standards.
Electrical Wiring Color Codes Meaning
The wiring color guidance provided below applies to the electrical wiring in the US. Although there may be instances where the color code is not followed correctly, this section can still be used to identify certain types of wires and their respective colors. Also, make sure that the wires are de-energized. Hot wires, which can carry live electrical currents from the electrical panel to light fixtures and outlets, are a major concern.
- Black wires are known as hot wires, which are wires that carry electricity. Before you can work with them, you must first shut off the circuit breaker. These wires go from a power source to various electrical outlets and switches.
- Red wires are referred to as secondary hot wires, which are wires that carry electricity. These wires can be used to connect various electrical devices, such as smoke detectors and ceiling fan lights. They can also be used to power outlets for 240v appliances, such as a dryer or air conditioning unit.
- White wires with red or black tape are referred to as hot wires. These wires are usually carried live electrical currents from the electrical panel to light fixtures and outlets. If you see a modified white wire with red or black tape around it, it means that it’s hot. These wires can then be used to replace the red wire in 240v outlets.
- Copper wires are referred to as ground wires. These wires are usually carried live electrical currents from the electrical panel to light fixtures and outlets. If a device goes out or trips a breaker, these bare wires will carry the current to the ground.
- Gray or white wires are also called neutral wires. These wires return power to a grounded section of the electrical panel. They act as a conductor, returning electricity to the breaker box.
- Blue and yellow wires are hot wire that usually found in a conduit, which is used to connect plug-in electrical devices. Blue and yellow wires are known as travelers, which allow lights or appliances to operate from different locations.
Infographics
Standard wire colors for flexible cable
Standard wire colors for fixed cable
US AC electrical circuit wiring color codes
In the US, the electrical code only requires that the power conductors be white or grey. Bare copper, green, or yellow stripes are the protective ground wires. In principle, other colors can also be used for the power conductors.
Red, blue, and black are commonly used for the 208 VAC three-phase conductors, while orange, yellow, and brown are used for the 480 VAC three-phase conductors. Power conductors with over 6 AWG are only available in blackwith red tape at the ends.
| Function | label | Color, common | Color, alternative |
|---|---|---|---|
| Protective ground | PG | bare, green, or green-yellow | green |
| Neutral | N | white | grey |
| Line, single phase | L | black or red (2nd hot) | |
| Line, 3-phase | L1 | black | brown |
| Line, 3-phase | L2 | red | orange |
| Line, 3-phase | L3 | blue | yellow |
US recommended DC electrical circuit wiring color codes
The electrical code for both DC and AC systems in the US generally requires that the power system’s neutral conductor be white or grey. The protective ground wire should be bare, green, or yellow-green. According to electrical inspectors, the first hot wire should be black, while the second should be red.
| Function | label | Color |
|---|---|---|
| Protective ground | PG | bare, green, or green-yellow |
| 2-wire ungrounded DC Power System | ||
| Positive | L+ | no recommendation (red) |
| Negative | L- | no recommendation (black) |
| 2-wire grounded DC Power System | ||
| Positive (of a negative grounded) circuit | L+ | red |
| Negative (of a negative grounded) circuit | N | white |
| Positive (of a positive grounded) circuit | N | white |
| Negative (of a positive grounded) circuit | L- | black |
| 3-wire grounded DC Power System | ||
| Positive | L+ | red |
| Mid-wire (center tap) | N | white |
| Negative | L- | black |
Europe IEC AC electrical circuit wiring color codes
Most European countries follow the guidelines of the IEC when it comes to the wiring color codes for their AC branch circuits. The protective ground wire, which is green with a yellow stripe, is the same color as the other wires.
| Function | label | Color, IEC | Color, old IEC |
|---|---|---|---|
| Protective earth | PE | green-yellow | green-yellow |
| Neutral | N | blue | blue |
| Line, single phase | L | brown | brown or black |
| Line, 3-phase | L1 | brown | brown or black |
| Line, 3-phase | L2 | black | brown or black |
| Line, 3-phase | L3 | grey | brown or black |
IEC DC electrical circuit wiring color codes
DC power systems, such as computer data centers and solar power plants, use the same color coding as the AC standards. The IEC also provides the same standard for the cables used in these types of installations.
| Function | label | Color |
|---|---|---|
| Protective earth | PE | green-yellow |
| 2-wire unearthed DC Power System | ||
| Positive | L+ | brown |
| Negative | L- | grey |
| 2-wire earthed DC Power System | ||
| Positive (of a negative earthed) circuit | L+ | brown |
| Negative (of a negative earthed) circuit | M | blue |
| Positive (of a positive earthed) circuit | M | blue |
| Negative (of a positive earthed) circuit | L- | grey |
| 3-wire earthed DC Power System | ||
| Positive | L+ | brown |
| Mid-wire | M | blue |
| Negative | L- | grey |
Canada AC electrical circuit wiring color codes
The Canadian Electric Code governs the wiring of electrical equipment in the country. The neutral wire is white, the single phase wires are black, while the three-phase lines are blue, black, and red. The protective ground wire is green with a yellow stripe (or green only).
| Function | label | Color, common |
|---|---|---|
| Protective ground | PG | green or green-yellow |
| Neutral | N | white |
| Line, single phase | L | black or red (2nd hot) |
| Line, 3-phase | L1 | red |
| Line, 3-phase | L2 | black |
| Line, 3-phase | L3 | blue |
UK AC electrical circuit wiring color codes
The UK follows the guidelines of the IEC when it comes to the wiring color codes for its AC branch circuits.
| Function | label | Color, IEC | Old UK color |
|---|---|---|---|
| Protective earth | PE | green-yellow | green-yellow |
| Neutral | N | blue | black |
| Line, single phase | L | brown | red |
| Line, 3-phase | L1 | brown | red |
| Line, 3-phase | L2 | black | yellow |
| Line, 3-phase | L3 | grey | blue |
UK electrical circuit wiring color codes
Some countries, such as Russia, China, UAE, and KSA, follow the International Electrotechnical Commission’s (IEC) cable color codes for DC. However, don’t expect the insulation colors in these areas to be the same as those used in older cables. Testers are required to confirm the neutral, positive, and negative wires’ phase and neutral, respectively.