The purpose of the bonding regulations is to keep all the exposed metalwork of an installation at the same earth potential as the metalwork of the electrical installation, so that no currents can fl ow and cause an electric shock. For a current to fl ow there must be a difference of potential between two points, but if the points are joined together there can be no potential difference. This bonding or linking together of the exposed metal parts of an installation is known as ‘protective equipotential bonding’ and gives protection against electric shock.
Fault protection is protection against electric shock under single fault conditions and is provided by protective equipotential bonding and automatic disconnection of the supply (by a fuse or MCB) in accordance with IEE Regulations 411.3 to 6.
Protection from electric shock is provided by basic protection and fault protection.
Protective equipotential bonding is equipotential bonding for the purpose of safety.
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Definition
- Earthing is the connection of the exposed conductive parts of an electrical installation to the main protective earthing terminal of the installation.
- Bonding is the linking together of the exposed or extraneous metal parts of an electrical installation for the purpose of safety.
Below figure is Simplified diagram of connections and equipment at a domestic service position.
- Exposed conductive parts are the metalwork of the electrical installation. The conduit, trunking, metal boxes and equipment that make up the electrical installation.
- Extraneous conductive parts are the other metal parts which do not form a part of the electrical installation. The structural steelwork of the building, gas, water and central heating pipes and radiators.
Fault protection is protection against electric shock under single fault conditions and is provided by protective equipotential bonding and automatic disconnection of the supply (by a fuse or MCB) in accordance with IEE Regulations 411.3 to 6.
Protection from electric shock is provided by basic protection and fault protection.
Protective equipotential bonding is equipotential bonding for the purpose of safety.
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| Protective equipotential bonding of gas and water supplies |
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