Used in electrical installations

There are four main reasons for grounding an electrical system. A person may receive an electric shock if the active conductor comes into contact with exposed metal structure of the appliance. To reduce this risk, all exposed metal parts of any device that the user may come into contact with must provide a low impedance path to ground for any active voltage that appears on the frame or metal structures. This will help ensure that any circuit protective devices, such as fuses or circuit breakers, are turned on, cutting off the power, rendering the faulty device safe.

This land is called the Protective Land. If an exposed metal part of the device was connected to a fault condition with an active conductor, then the active current path must be capable of flowing to ground through a low impedance path such that excessive current will flow, resulting in a protective device such as a fuse or circuit breaker to open the circuit, thereby preventing an electric shock situation.

Circuit protection devices are also required to protect wiring from overcurrents, while ensuring maximum demand for a protected circuit. Fuses These can be fast impact, slow impact and semiconductor. Excess current causes the fuse to break or burn out, creating an open circuit. They must be replaced every time they work, but for most applications they are low. Circuit Breakers These magnetic devices are either current or thermal sensitive, in which case they use the thermal effect to activate a mechanical switch.

Circuit breakers may have different characteristics trips according to applications such as motor starting, where the initial high starting current can be tolerated, but the high fault current will cause the circuit breaker to trip, thereby tripping the overload. It is important to remember that it does not provide protection when a person comes into contact between Active and Neutral, as there will be no imbalance. It is primarily designed for active earth fault detection.

A thermistor is a type of resistor whose resistance increases with increasing temperature, as in the case of a positive temperature coefficient thermistor, or decreasing temperature, as in the case of a negative temperature coefficient thermistor. They are used as inrush current limiters or self-resetting overcurrent protection and temperature sensors.

They can be used as a resettable fuse, but they "switch off" every time. their resistance increases slightly to the point that they are unusable, so they need to be replaced regularly to ensure reliable operation.

The surge vent diverts excess energy such as excess voltage to ground. They can be installed in distribution boards, including specialized lightning surge diverters, as well as portable ones in power boards.

Some of them are reset, but most of them are not the way the manufacturer usually wants the cause of the overheating to be investigated. Metal Oxide Varistors Metal Oxide Varistors are semiconductors that protect electronic components and systems from transient voltages.

Minimize fire hazard

If the equipment becomes faulty with the live wire touching the frame, current will flow to ground, smoke will rise from the equipment, and, if the current is very high, the fuse in the live line will blow, cutting off line power to the faulty appliance. Standards that limit the current in any circuit are vital to preventing electrical wires from becoming overheated and causing fires.

The neutral point allows the vector sum of the three phase currents offset by 120 degrees, reducing them to zero. The secondary purpose is to detect earth faults or earth leaks and allow the protective device to operate at the required time.

In terms of the high harmonic content found in modern facilities, zero-sequence or triplex harmonic currents overload the neutrals if they are not of sufficient size. This is because they are in phase and therefore do not cancel out at the neutral point. Thus, the neutrals must be of a size equal to or sometimes double the size of the line conductors to carry the "algebraic sum" of the ternary components in the lines.

These fault currents must be large enough to cause the protective devices to operate. In the diagram, the neutral conductor of an electrical distribution system provides a low-impedance return path for fault current. This would limit the magnitude of the fault current to a value that may not be sufficient to cause the protective device to operate. If the protective device does not operate, dangerous voltage may remain on the metal frame of the device or equipment.

The ground resistance from the protected grounded parts in Class 1 equipment must be low enough to provide sufficient fault current to ground, thereby ensuring that the overcurrent protective device in the final subcircuit opens quickly in the event of an insulation failure.

The protective grounding conductor also ensures that any leakage current from live parts in Class 1 equipment flows harmlessly through a low resistance path to ground. All Class 1 equipment must test the integrity and resistance of its grounding conductor at regular intervals during its service life to ensure that connections have not been loosened, transposed or corroded.

Protective bonding or equipotential bonding

Ground bonding helps protect people and equipment from electrical faults, power surges, and other power surges and transients. Grounding the ground also helps reduce noise and other forms of interference. Proper bonding helps ensure that people are not exposed to voltage potentiometers between two metal surfaces, such as bathroom faucets or electrical control cabinets.

Alternatively, such accessible parts shall be separated from parts which are hazardous in the live state by means of a conductive protective shield or barrier associated with the protective conductor terminal. Accessible conductive parts shall not be connected to the protective conductor terminal if they are separated from all hazardous parts.

This protective connection is known as an equipotential connection. Metal bathroom fittings must be connected to the floor reinforcement mesh, which must be connected to a protective earth by an electrician. Public swimming pools must have metal reinforcing bars and all metal pipes bonded together, then connected to the protective soil.