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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.
A multipoint ground system is more complicated to install and maintain over the long term, and can be more expensive to install. Star topology systems can be converted to multipoint systems by installing new conductors between old existing ones. However, this should be done with care as it can inadvertently introduce noise onto signal lines during the conversion process. The noise can be ...
Equipotential bonding involves electrically connecting metalwork so that it is at the same voltage everywhere. Exact rules for electrical installations vary by country, locality, or supplying power company. [2] Equipotential bonding is done from where the distribution wiring enters the building to incoming water and gas services.
A ground fault protection relay must trip the breaker to protect the circuit before overheating of the resistor occurs. High-resistance grounding (HRG) systems use an NGR to limit the fault current to 25 A or less. They have a continuous rating, and are designed to operate with a single-ground fault.
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.
The ground loop still exists, but the two sides of the loop are close together, so stray magnetic fields induce equal currents in both sides, which cancel out. Break in the shield Create a break in the signal cable shield conductor. [5] The break should be at the load end. This is often called ground lifting. It is the simplest solution; it ...
Several methods may be used to protect employees from hazardous ground-potential gradients, including equipotential zones, insulating equipment, and restricted work areas. The creation of an equipotential zone will protect a worker standing within it from hazardous step and touch voltages.
A ground connection that is missing or of inadequate capacity may not provide the protective functions as intended during a fault in the connected equipment. Extra connections between ground and circuit neutral may result in circulating current in the ground path, stray current introduced in the earth or in a structure, and stray voltage.