Table of Content

• Wiring Color Codes
• Color Codes are used to Represent the Resistance of Different Resistors
• Types
• Wiring Color Codes for AC Power System
• Wiring Color Codes for DC Power System
• Properties of Wiring Color Codes
• Standards of Wiring Color Codes
• Advantages and Disadvantages of Wiring Color Codes

Note:- Different countries have different wiring color codes.

Color	1st Band	2nd Band	3rd Band Multiplier	4th Band Tolerance
Black	0	0	x1Ω
Brown	1	1	x10Ω	±1%
Red	2	2	x100Ω	±2%
Orange	3	3	x1kΩ
Yellow	4	4	x10kΩ
Green	5	5	x100kΩ	±0.5%
Blue	6	6	x1MΩ	±0.25%
Violet	7	7	x10MΩ	±0.10%
Grey	8	8	x100MΩ	±0.05%
White	9	9	x1GΩ
Gold			x0.1Ω	±5%
Silver			x0.01Ω	±10%

History of Wiring Codes

The Electrical Appliances (Color Code) Regulations 1969 came into effect on 1 July 1969. This regulation ensured that a set of rules and an industrial color code pattern must be followed worldwide.

This included four major color codes for industry as well as for domestic purposes:-

• Brown for live – Live wire means that the wire is connected to the main supply. So, brown color was used indicating this property of the wire.
• Blue for neutral – Neutral wire shows the returning path of the current from appliance to source. Sp, blue was used to indicate this property.
• Green for Earth – Earth wire means a safety wire that protects the appliance from electrical shocks. So, green color was used for this purpose.
• Yellow for Earth – Yellow wire is used for the high voltage for lights, fans. Also it is used for safety so that current of live wire can not pass directly to casing.

Evolution of Wiring Color Codes

From 1st July 1969 after The Electrical Appliances (Color Code) Regulations, wiring color codes have changed a lot. Different countries started adopting their color code standards.

According to the Old Standard of Color Codes in India

• The red color is used for live.
• Black color is used for neutral.
• The green color is used to protect the earth or ground.

New Terminologies of Indian Standard Color Code

Note:- Different terminologies are used for single-phase and three-phase wire systems. 

For Single-Phase Wire System

• The Brown color is used for live.
• The Blue color is used for neutral.
• The Green color is used for earth.

For Three-Phase Power Supply

• The combination of Red, Yellow, and Blue are used for the active line power conductors.
• Black color is used for neutral.
• Green or Green – Yellow for protective ground

New Standard for Three-Phase Power Supply

• The combination of Red, Yellow, and Blue are used for the active line power conductors.
• Black color for the neutral conductor.
• Green or Green – Yellow for protective ground.

Types of Wiring Color Codes in India along with their Properties

• Single-phase wiring
• Three-Phase Wiring
• Control Wiring System

Single-Phase Wiring

Single-phase wiring is mainly used for residential or domestic purposes. In this following color codes are used:-

• Red: Red wires are used as phase wires and they carry electrical current.
• Black or Yellow: These wires are used for neutral wires. These wires complete the circuit and provide a return path.
• Green or Green with yellow stripes: These wires are used as grounding conductors. They also reduce the risk of electric shock.

Three-Phase Wiring

Three-phase wiring is used for industrial purposes. In this following color codes are used:-

• Red, Yellow, Blue: These wires carry alternating currents with a 120-degree phase difference between them.
• Black: It is used for neutral connection and it also provides a return path for unbalanced currents.
• Green: It is used for grounding conductors.

Control Wiring System

It is used for low-voltage signals to control various electrical devices. In this following color codes are used:-

• Red: It is used for power supply lines for control circuits.
• Yellow: It is used for interlock and safety circuits.
• Blue: It is used for control signal lines.
• Black: It is used for grounding.

Wiring Color Codes for AC Power System

As discussed earlier wiring color codes are used to identify and distinguish between the conductors having different functions. So, let us discuss the wiring color codes for the AC power system, in which an AC supply is supplied to the system.

Phase conductor (Line or Live)

• Single phase: A single-phase system is common in residential wiring in which Red or Brown color is used. This shows that the wire is connected to the single-phase supply.
• Three-phase: Three-phase systems are commonly used for industrial and commercial purposes in which Red, Yellow, or Blue are used for the three-phase system.

Neutral Conductors

• Light Blue or Black color is used for neutral conductors. It shows a return path of the current to the source.

Earth Conductor

• Green or Green with a Yellow strip is used for earth conductors. It ensures safety by providing an earth connection.

Wiring Color Codes for DC Power System

The wiring color codes for the DC power systems are not as standardized as AC power systems. Different appliances and different industries have their different wring color for DC power systems.

However a common wiring color code for DC power systems:-

• Positive voltage : Red or orange is used for positive voltage or to indicate the positive terminal of the battery or conductor.
• Negative voltage : Black or Blue to indicate the negative terminal of the battery or conductor.
• Earth conductor : Green color is used to indicate the earth conductor or safety terminal.

Properties of Wiring Color Codes

In this section, we are going to discuss the properties of wiring color codes-

• The major property of wiring color codes is to identify and distinguish between different wires or conductors. The different colors used for color codes specify a unique function which makes the identification very easy.
• Another major property of wiring color codes is that They ensure the safety of the appliances and the person working on them.
• Wiring color code is that it makes requirements and maintenance very easy.
• Standardized color codes make it very easy for a person from one country to work or repair some appliances in another country.

Standards of Wiring Color Codes

Until now we have focused our discussion on the Indian wiring color codes only, since every country has its wiring color codes. But some of the common color codes accepted in every country are called Standard wiring color codes.

Some standard Wiring Color Codes for AC Power System are as follows:

Phase Conductors (Line wire)

• Black color is used in single-phase systems.
• The red color is used in 3-phase systems.
• The brown color is used in 230V single-phase systems.

Neutral Conductor

• White or Gray color is used for the neutral conductor, which carries the return current.

Earth Conductor

• The green color is used for the grounding conductor for safety.

Standard Wiring Color Codes for DC Power System

• Positive Voltage – Red or Orange is used to indicate the positive terminal of the battery or conductor.
• Negative Voltage – Black or Blue is used to indicate the negative terminal of the battery or conductor.
• Earth Conductor – Green or Green with a Yellow strip is used to indicate ground.

Benefits of Standard Wiring Color Codes

The benefits of standard wiring color codes are the same as the wiring color codes. But this has one major advantage as having the standard wiring color code is that it helps everyone from any country working with the appliances safely.

Advantages and Disadvantages of Wiring Color Codes

There are some list of Advantages and Disadvantages of Wiring Color Codes given below :

Advantages of Wiring Color Codes

• It helps us to identify specific wires.
• It ensures safety as it provides a visual of the wire’s purpose and also provides protection to those working on it.
• It ensures safe and effective electrical installations and maintenance.
• Color codes are the reason for the production of machinery in one country and shipped worldwide.

Disadvantages of Wiring Color Codes

Though wiring color seems very important for industry and domestic purposes it still has a few major disadvantages.

• Color codes are very difficult for color-blind people to work on.
• Overheating or dirt accumulation sometimes makes it difficult to distinguish between similar colors like brown and red.
• The use of many colors may sometimes lead to confusion.

FAQs on Wiring Color Codes

Do wiring color codes vary from country to country?

Yes, different countries have different color codes.

Are there exceptions to these common color codes?

Yes, some specialized applications or may use different color codes. Always follow the local electrical wiring code and any manufacturer instructions when dealing with non-standard colors.

Are there any safety considerations when working with wiring color codes?

Yes, following the correct color codes is crucial for safety. Incorrect connections can lead to electrical hazards, equipment damage, or non-compliance with local electrical codes.