What Is Electrical Earthing?

When a short circuit occurs this leads to high voltage or electrical supply currents to leak out of their original path. When this happens it will travel to the nearest conductor which can be either people or appliances. To prevent major damages to people or appliances earthing conductors and systems are installed. The earth connection is the third pin on a power plug of an electrical appliance. 

Ground is a good conductor of electricity which is why diverting the leaked current to it is important. It will safely transfer the flow of electrons and discharge to the earth or ground via a low resistance wire. The leakage will escape the device and divert to the earth meaning that damages to the appliance or a person are prevented.

There are three main reasons why electrical earthing is installed and devices are connected to the earth:

• People – if a device is not properly earthed and the current leaks while a person is using the device the fault current will pass through them. This can cause a person to be electrical shocked and can be fatal in some cases. 
• Electrical Equipment – appliances will need to be protected by electrical earthing systems. This is to ensure that the excessive voltage or over-current does not cause the device to malfunction. The large amount of current can cause the wires and cable to overheat quickly which is why earthing is also used to help with preventing electrical fires.
• Lightning Protection – to protect homes and buildings from lightning strike damages a lightning rod is connected to the roof. These will divert the lightning strike to the rod which is connected to ground so the current does not interfere with the home.

There are many different ways electrical systems can be connected to earth and there are many types of grounding systems:

• Neutral – a GI wire connects earth directly to the neutral of a system. This is used for systems with star wounding, such as generators, motors and transformers. 
• Equipment – electrical equipment will use this type of earthing system to protect them. A non-current part of the equipment is connected to the earthing system by using a conducting wire. When a fault occurs the short circuit will pass through the wire and make contact with the earth. 
• Plate – this involves a galvanised iron or copper plate being buried in the ground by digging up the earth in a pit form. This is where the earthing system will divert the current leakage into the ground.
• Pipe – a galvanised steel pipe can also be used and will be inserted into the soil. There will be holes drilled to connect the earth wires and the pole shape will be influenced by the electrical installation and type of soul.
• Rod – this is similar to using the pipe method but involves a rod being buried into the soil.

A qualified electrician will perform earthing testing on electronic devices and systems using professional test equipment and test methods. Assessing the ground circuits and systems on their performance and potency is important. Seeing if they properly allow a low-resistance path for leaked electricity to travel away from the system is key. The main test methods are soil resistance test, fall-of-potential, stakeless and selective.

For more information about electrical testing, including how often it should occur and a more in-depth explanation of the different methods, our blog is here for additional help.

The process of eating installation is where a certified electrician installs earthing systems into properties. Most times the electrical earthing system is installed by firstly locating where the soil has enough moisture, resistance, salts and other factors then digging up a pit. The electrical earthing unit, such as a copper plate, will be installed in the pit. After ensuring all other parts are installed correctly an electrical test will be performed at the end of the installation.

We encourage reading our blog that contains a more detailed explanation of the steps of earthing installation and to know additional facts.