Understanding the Wire Colours connected to Electrical Appliances

Wire Colours connected to Electrical Appliances
wire colours

All electronic appliances comes attached with a power cable for connecting to electricity outlet in your house.The power cable may contain 2 or 3 wires. A power cable with 2 wire colours are in RED and BLUE. A power cable with 3 wires have the colours GREEN, RED and BLUE.

Meaning of the wire colours

The Wire colours have their meanings and It is briefly explained below;

Red colour : Live wire

Brown or Black colour : Live wire

Blue or White colour: Neural wire

Green or Yellow colour: Earth wire

In some places, the live wire is black in colour and the neutral wire is white.

The red or brown wire is “LIVE” as the name implies, electric current flows through this wire. The live wire supplies electric current to the appliance. You should take care when you handle this kind of wire. It can cause an electric shock

The blue wire is “NEUTRAL” . This wire do not give a shock upon touching it or show a red light through a tester. In reality it carries electric current back to the power source. It is the neutral wire that allows the current to alternate. Neutral wire is an integral component of an AC power system.

The green wire is “EARTH” . The purpose of this wire is to remove excess electric charges that might be on the connected appliance and drive them into the earth. It is good practice to earthen electrical appliances to prevent any form of electric shock upon contact. The Earth wire is usually connected to a metal rod driven into the ground.

Some electrical appliance come with just the live and neutral wire. This is Ok. But you are always at a risk of receiving electric shock from contact with the appliance when connected to electricity. This usually happens when the electrical appliance is faulty.

The live wire supplies current to the appliance, the neutral wire carries it back and the earth wire is to serve as protection from electric shock.

Understanding Power Ratings of Electrical Appliances.

Every household electrical appliance, always have its power rating labelled on it. Power rating is very important as it gives information regarding its power consumption.

Knowing the power consumption rating of your electrical appliance will help understand and analyze your electrical bills. It will also help when you have to determine the capacity of generator or inverter you will need to power up your appliances.

There are two important information to look out for in a power rating label;

  1. Voltage rating  (v)
  2. Power rating   (w)

You should always check the voltage rating of any appliance you buy, this is necessary to make sure it is not different from the voltage rating supplied to your home.

Since electrical bills are determined by power consumption you should always check power ratings of your electrical appliances to have good idea of how much you would be paying for electricity by the end of the month.

Power consumption on electricity bills is usually measured in kilowatt hour (kwh).

For example, an electric fan with a power rating of 50w will consume 50w in one hour or 50/1000 kwh = 0.05kwh.

An electric cooker with power rating of 2500w and used for 2 hours everyday will consume 2500 x 2 = 5000w in 2 hours or 5kwh. (Note: 1kw = 1000w). Doing this every day for the month you consume 5 x 30 = 150 kwh! Just for using the electric cooker!..

Total power consumption of all active electrical appliance in your house is added up by your electric meter. You pay for total electrical power (kwh) consumed every month.

It is very important to switch off electrical appliance when not in use to save cost of electricity bills.


Direct current (DC)

The Direct current (DC) is simply electric current that flows in one direction. It usually flows from a battery source. It also means electric current with one polarity of current or voltage.

Uses of DC

DC is often used to power low voltage appliances such as flashlights, toothbrushes, calculators, telephones and so on, although it can also power high voltage appliances.

Sources of Direct Current Supply

 Common sources of DC supply includes solar cells, batteries and DC generator.

Drawback of Direct current (DC)

The major drawback of Direct current (DC) is that it cannot be transmitted through long distances without considerable power loss. The power plant or source of direct current (DC) supply must be within 3km of the appliance which implies that direct current power plant/supply must be installed in every household.

Alternating Current (AC)

 Alternating current rapidly changes in direction. AC is transferred at very high voltage (kilovolts) over long distances and then stepped down with a transformer to between 100-240 volts at point of use.  

Uses of AC

AC is often used to power appliances that require higher voltages examples include fans, air conditioners, cookers, tvs ,  water heaters, pressing irons and so on

Advantage of Alternating Current

The major advantage of AC is that it can travel hundred to thousands of kilometers without considerable power loss making it possible for the location of central alternating power supply stations far from point of use.

Comparing Alternating to Direct Current

It can be argued that AC holds no practical advantage over DC. As stated earlier, DC is preferred over AC for low voltage appliances while AC is preferred to DC for high voltage appliances. However it is possible to build power supply/distribution systems that are more efficient with AC than DC and this is one reason why the AC is far more popular.