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An earthing system (UK and IEC) or grounding system (US) connects specific parts of an electric power system with the ground, typically the equipment's conductive surface, for safety and functional purposes. [1] The choice of earthing system can affect the safety and electromagnetic compatibility of the installation.
Low-resistance grounding systems use a neutral grounding resistor (NGR) to limit the fault current to 25 A or greater. Low resistance grounding systems will have a time rating (say, 10 seconds) that indicates how long the resistor can carry the fault current before overheating.
For building electrical grounding systems or earthing systems, there is a low resistance conductor bonding the metalwork and this is connected to a groundbed. The electrodes for electrical grounding are often called ground rods and are often made from steel with a copper clad surface – typically 1 to 2 m long and 20 millimetres (0.79 in) in ...
A good ground resistance is 5–10 ohms which can be measured using specialist earth test equipment. SWER systems are designed to limit the electric field in the earth to 20 volts per meter to avoid shocking people and animals that might be in the area. Other standard features include automatic reclosing circuit breakers . Most faults ...
Even if all of the audio and video equipment in, for example, a home theatre system is plugged into the same power outlet, and thus all share the same ground, the coaxial cable entering the TV may be grounded by the cable company to a different point than that of the house's electrical ground creating a ground loop, and causing undesirable ...
The ground serves as a capacitor plate to receive the displacement current from the antenna element and return it to the feedline from the transmitter. The ground connection must have a low electrical resistance, because it carries the full antenna current and any resistance in the ground connection will dissipate power from the transmitter ...
Current flowing in a grounding conductor will produce a voltage drop along the conductor, and grounding systems seek to ensure this voltage does not reach unsafe levels. In the TN-S system, separate neutral and protective earth conductors are installed between the equipment and the source of supply (generator or electric utility transformer).
An isolated ground (IG) (or Functional Earth (FE) in European literature) is a ground connection to a local earth electrode from equipment where the main supply uses a different earthing arrangement, one of the common earthing arrangements used with domestic mains supplies.