For an electrical installation to be reliable and not endanger the safety of the occupants of a dwelling, it must respect the NF C 15-100 standard. Among the essential elements mentioned by the text, we find the grounding. But what is behind this term? DelightFire reveals everything you need to know about the earth.
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What is the purpose of grounding?
Grounding is a key element in ensuring the protection of people. È green and yellow electrical wires, recognizable among thousands, allow to conduct the current to the ground in case of leakage. This is how many electrocutions can be avoided. For a grounding system to be effective, it is necessary that :
- That the device has a grounding connection (third female plug);
- That the appliance is connected to a grounding outlet (with a male plug) or connected to a ground wire for the elements added to the electrical installation by means of a domino or a Wago connector;
- That the circuit continues to the grounding strip of the electrical panel;
- That the strip of the distribution board joins the general grounding of the dwelling.
Da 2015, grounding has been essential for electrical installations in new buildings and renovation. It is also one of the devices that will be verified during the electrical diagnosis required for a property sale.
Good to know: no exception for earthing
Grounding is an obligation of the NF C 15-100 standard that cannot be waived. Così, if it is possible to install shaver plugs without a plug-in bathroom, these elements will still have an earth connection for equipotential protection. These plugs can only be used for the connection of double-insulated appliances (class II).
What equipment must be grounded?
To ensure the safety of all, the following elements must be grounded.
Socket outlets;
Class I appliances (radiatori, large household appliances, eccetera.) which have an earth terminal marked with the symbol ⏚ ;
Equipotential connections in buildings, cioè., elements containing metal parts that may be conductive (the metal door or window frames, pipes, eccetera.) ;
Equipotential connections in bathrooms (a requirement of the NF C 15-100 standard for bathrooms) ;
The VDI (voice, data, and image) network ducts such as the GTL communication box.
How to make a grounding?
The dwelling must be connected to a general grounding to evacuate the surplus of electric current to the ground. For obvious safety reasons, an electrician should take care of this work. Do not hesitate to contact your local electricity agency to get the contact information of a professional. He will have two options for installing your grounding:
Down-the-hole method
The conductors from the electrical panel will be buried horizontally in the ground. When building a new house, foundation trenches are often used, and it is also possible to provide a dedicated trench of about 1 meter deep. For good conductivity, the trench should be filled with soil rather than gravel.
Earth stake method
This is the most commonly used method. It is suitable for new construction and grounding in case of renovation of the electrical installation. It brings the surplus of current to one or several galvanized steel poles driven into the ground. Each stake will measure at least 1,50 m. If there are several poles, they must be installed at a distance of at least 2 metri.
When your electrician installs the grounding, he will study the nature of the soil to determine its resistivity of the soil. Expressed in Ohm, it determines the length of wire that must be buried (or the number of stakes and their depth) to adapt to the resistance of the general grounding.
Mandatory since 2015, grounding is essential to enjoy a safe electrical installation. For a construction or renovation project, call on an expert to ensure a grounding to standards adapted to your home.
