A Beginner’s Guide to Colour Coding in Circuitry


When it comes to differentiating wires and combinations in the electrical system, it would purely be a momentous task without colour coding. Although each wire has markings based on their gauge, amperage, voltage and temperature on the outer coating, it gets difficult to identify the source it is connected to. And over-time, the reading on the wires simply goes off, making it nearly impossible to differentiate.

In case you are a consumer, willing to educate yourself about wiring systems of your office or home, here are some of the basic facts about wiring you need to know before understanding the colours coding:

An electrical circuit has three wiring component —live or hot and main, neutral and ground.

The colour coding standards of wires are different across countries. The colour codes are decided by the national or international organizations like the National Electric Code based on the standard electrical installation practices across different regions in India.

In India, we follow the RGB—red, green and black scheme.

Red: The colour red in the electric circuit refers to the live wire. The red wires are used in switch leg that balances the load. Each time in a switch is turned on and becomes hot, the red wires at the bottom of the switch’s terminal comes off. These red wires cannot be mixed or connected with other red wires or even black wires.

Green: Green wires are used for grounding or earthing in an electrical circuit and attached to appliances like AC, TV, microwave, water heaters and geysers and connected to the junction box. The colour green is to direct a pathway in the ground for the electric current to flow without causing shocks and electrocution. Grounding wires are not connected to lighting and fan sockets. Also, they cannot be connected to wires of any other colour.

Black: Black is used for neutral wires or voltage transmission wires meaning, they carry unbalanced load or unused electric current to transfer it back to the electric panel. Inside the electric panel, these black wires are attached to the part called neutral bus bar or a highly conductive metal bar that draws electric current for disbursement. The black wires are meant to be connected to other wires except for black wires.

In addition to the above standard colour coding, the electricians have also been following a new coding method with BBG or brown, blue and green. Brown represents live wire, blue is for neutral wire and green for earthing.A green wire striped with yellow or just a bare conductor like copper wire is used for earthing purposes.

Blue and Yellow: These are also popular colour codes that we can find for usage in connecting live wires. In fact blue or yellow wires are found inside of a conduit. Yellow wires are also used in switch legs and connected to fans, blubs, tube lights and other household appliances. Sometimes the blue and yellow are also used in live or hot wiring and for phase 3 connections.

Grey and White: These colours represent neutral wires and white colour code is more popular than grey. They share direct connection to bus bar in the electrical panel and should only be connected with other grey or white wires.

We hope the above information would be useful for making your home or office’s wiring plans. For more details on safe and tested electrical cables and wires.

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