Earthing the electrical installation
Whatever the type of building, an electrical installation needs to be earthed in order to ensure your safety. Earthing a new building is done using an earthing loop, whilst earth rods are used for renovations.
Why earth?
The goal of this technique is to protect both assets and people. If one of your appliances is defective, evacuating fault currents to the earthing will ensure safety and prevent electrocution.
The process consists of creating a conductive bond between an electrical installation or an electrical appliance and the earth. If an insulation fault is detected, the current will be automatically cut off by an earth fault interrupter.
More concretely:
- The PE conductor wire must be distributed with all circuits: lighting and outlets.
- All metal components in the building are also earthed. These are the main and additional (primary and secondary) forms of equipotential bonding.
Earthing an electrical installation is mandatory in Belgium, whether it is a new building or an upgrade for a renovation. It must be validated by an certified inspection body and comply with the Règlement général sur les installations électriques (RGIE, ‘General Regulations for Electrical Installations’).
Earthing loop for a new building
For a new building whose foundation is at least 60 cm deep, the procedure involves an earthing loop with a cross-section of 35 mm2. It is installed at the base of the foundation parallel to the external walls and is covered with soil in order to prevent any contact with foundation materials. The ends of the loop must remain accessible and come together at the ground switch.
Earth rod for renovation
For an existing building with no or defective earthing, one or more earth rods must be planted into the soil. The minimum distance between two earth rods is 3 m. The tip of each rod must be inserted to a depth of at least 2.10 m in relation to the surface level. The end must be buried to a minimum depth of 60 cm and connected to the earth clamp by means of a PE conductor wire with a minimum cross-section of 16 mm2.
Equipotential bonding
- The main or primary equipotential bonding connects all the metal structures of the building to the earth clamp by means of a PE conductor wire with a minimum cross-section of 6 mm2. The relevant metal structures are steel beams, water pipes, gas pipes and heating pipes, as well as all the metal components in the building.
- The additional or secondary equipotential bonding connects the metal structures of the bathroom or shower room (bath tub, heating, outlet earth terminals) by means of a PE conductor wire with a minimum cross-section of 2.5 mm2. This connection can be made either to the earth clamp of an outlet in the bathroom or to the earth terminal of the BT electrical box.
Need to ground your building? Renovating a house and need to bring your electrical installation in line with regulations?
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