Earthing: Checkmate Death By Electrocution in Our Homes

Electrical earthing or ground is the process of making a path of least resistance to ground in the event of a fault current. This is because electricity usually flows from path of least resistance to the lower potential.

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The standard electrical connection comprises three wires. They are the live, neutral and earth.

Single phase cable: Earth is the yellow-green stripped cable,live is reddish-brown and neutral is blue

A typical UK standard three-pin 13A plug showing the three wire connection. 1=Cable clamp,2=Neutral, 3=Earth, 4=Live, 5=Fuse

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In a single phase system involving three wires, the earth or protective ground cable is usually color-coded to be either green or green with yellow stripe depending on the country or region.

• Live: carries the current to the electric equipment.

• Neutral: completes the circuit by forming a path back to the mains. It is usually at zero volts.

• Earth is the very low resistance wire connected to the metal casing of devices and connected to the earth in case the appliance becomes "live" (energized).

How Does Earthing Prevent Electric Shock?

^{Source: Free Google Image showing an electric washing machine connection showing earth connection}

First a look at how electrocution works. Electrocution is when a person comes in contact with a live wire and electricity flows through the person. But how do birds manage to perch on live wires and not get electrocuted? It is simply due to the principle of how electricity works, you need to close (complete) a circuit. The birds only perch on the one wire, that wire alone cannot electrocute them. But while flying away, if their wings inadvertently touch a grounded pole or wire while the feet are still on the wire, the circuit is then complete and the bird would be electrocuted.

Electricity also flows through the part of least resistance and basically, the earth connected to the metal part of an electrical device provides that path. So when the live wire insulation fails, the equipment is now live and could electrocute anyone that touches it. But when someone touches it, instead of the electricity to flow through him, it follows the part of low resistance which is via earth wire to the earth. This current (fault current) now moves and trips the circuit breaker thereby making the equipment safe and the person touching it not to be electrocuted.

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If there was no earthing in location and fault current would see the person touching the equipment as the part of least resistance and would flow through the person resulting in electrocution.

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Advantages of Earthing

1. Prevents damage, injury, and death. It protects the user from electric shock by its provision of the path of least resistance for fault current.

2. It protects the equipment in the event of surges, lightning or any abnormality that may damage our electrical equipment. If your electrical system is grounded, all of that excess electricity will go into the earth rather than fry everything connected to your system.

3. It makes for easier distribution of electric power, by ensuring circuits are not overloaded. It is a common reference point for many voltage sources in an electrical system
   
   

From my little observation, I noticed most houses in Nigeria are not earthed. Most technicians also do not take earthing serious. A case in point, watch whenever most electricians are changing the plugs of devices such as electric pressing iron, what they do first is cut off the earth cable! If you ask, they would tell you it is not useful!

Most home builders do not run earthing connection in like 40% ( this is a conservative estimate) of buildings.

Here is an earth cable terminated to the earth rod.



^{Free Google Image showing an earth cable connected to an earth rod which was driven into the earth}

Check if your house has an earth connection if in doubt invite an experienced electrician to run a check. Earth also fails after some time. Some house has an earth connected but not functional.

Be safe. Take all the precaution possible.

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