What is an earthing connection?

Let us start with the definition: earthing connections, also known as simply "earthing", connect the plugs of electrical appliances to earth. What are they used for? How do they work? Here are seven points to explain everything clearly.

What are earthing connections designed for?

They are mainly designed for safety purposes. The earthing connection diverts the flow of electric current to a space where no accidents can occur if there are problems in the electrical installation due to an earth leakage, stray current or electric shock caused by lightning. They prevent electric shocks that could be caused by touching the electrical appliance in these cases.

Earthing connections are also designed with protection in mind: they protect electrical devices to ensure their proper functioning, since they improve the electrical signal and the electrical installation as a whole.

Finally, they reduce the electromagnetic noise levels, so they are very common in sound devices.

How do earthing connections work?

Earthing connections are easy to identify: earthing connections are found in the form of the third cable or wire of your home installation, your home's power sockets or in your household appliances. They connect conductive materials, such as metal, to earth, diverting the electricity from the conductor to a place where it does not cause damage (such as earth, where it is dispersed). In the case of a household's earthing connection, it must be anchored under earth to prevent damage. This general earthing connection is usually connected to the power sockets to divert the current that could be dispersed from each one.

Earthing connections are easy to recognise, since they have green and yellow cables.

How is an earthing connection installed?

An expert technician must install and handle all earthing connections, due to their complexity and to the associated risks. Keep in mind that some very old homes may not have an earthing connection or this connection may have deteriorated over time. Therefore, it is necessary to inspect your electrical installation at regular intervals.

In addition, you must bear in mind that there are specific laws.

What elements must be connected to the earthing connection?

The boiler, elevator cables, pipes, concrete walls and other elements must be connected to the earthing connection, i.e., the conductive elements inside a home.

The TV antenna must also be connected to the earthing connection. It is highly exposed to electric shocks caused by lightning, due to its design and place of installation.

Moreover, the lighting arrester must also be connected to the earthing connection, according to its design purpose.

How is the differential switch associated with the earthing connection?

The differential switch is designed to protect your electrical installation against earth leakages to prevent electric shock to people or pets. Therefore, when current is detected between the protection cables of the earthing connection or on the earthing connection's cables of a plug or electrical appliance, these are disconnected automatically.

To do so, measure the input and output amperes: if it detects a difference in voltage, this means that there could be a risk of electricity leakage, so it is triggered and cuts off the electricity.

What are earthed sockets and plugs?

Let us start with power points. In Spain, most sockets have two horizontal holes, into which the electrical device's plug is fitted. You will see two tabs on the top and bottom of the socket: these are earthing connections. They are connected to the general earthing structure under the building.

In the case of plugs, Schuko plugs are used. These types of plugs usually have a metal groove on the top and bottom, into which the socket's tabs fit when the plug is inserted. These grooves are connected to the green and yellow wires mentioned above. The cables are connected to the areas that can be touched by people or pets, and which have conductive materials.

Therefore, electrical appliances featuring a plug with an earthing connection are much safer than those that do not have one.

What maintenance do earthing connections require?

The maintenance intervals and requirements are established in the corresponding laws. However, it is important to check your installation more often in some cases. It is essential to ensure that there is contact between the electrode and earth. Due to its nature or in the event of high temperatures, it can dry out or crack, which will lessen the degree of contact and thus reduce the resistivity of earth. Specific products can be used to prevent this phenomenon from occurring, which should always be applied by an expert, since acids or salts can rust and damage the earthing connection's materials.

The technicians will choose the best location for the earthing rods (the element in direct contact with earth), at the most suitable distance from the surface (depending on the type of weather in the area and type of building) and at a safety distance from river basins, wells, lakes, pipes, groundwater, power stations, power cables, etc.

All in all, earthing protects your home against electric shocks and is an essential part of your electrical installation and appliances. Ensuring your home is protected will allow you to enjoy day to day safely.