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In that case, circuit protection devices may detect a fault to a grounded metal enclosure and automatically de-energize the circuit, or may provide a warning of a ground fault. Under certain conditions, a conductor used to connect to a system neutral is also used for grounding (earthing) of equipment and structures.
In single-ended single-phase systems where the Earth and neutral are combined (TN-C, and the part of TN-C-S systems which uses a combined neutral and earth core), if there is a contact problem in the PEN conductor, then all parts of the earthing system beyond the break will rise to the potential of the L conductor.
This is called "system grounding" and most electrical systems are required to be grounded. The U.S. NEC and the UK's BS 7671 list systems that are required to be grounded. According to the NEC, the purpose of connecting an electrical system to the physical ground (earth) is to limit the voltage imposed by lightning events and contact with ...
Neutral to earth voltage (NEV) specifically refers to a difference in potential between a locally grounded object and the grounded return conductor, or neutral, of an electrical system. The neutral is theoretically at 0 V potential, as any grounded object, but current flows on the neutral back to the source, somewhat elevating the neutral voltage.
[2] [4] Neutral grounding transformers are very common on generators in power plants and wind farms. [2] Neutral grounding transformers are sometimes applied on high-voltage (sub-transmission) systems, such as at 33 kV, where the circuit would otherwise not have a ground; for example, if a system is fed by a delta-connected transformer.
United States electrical codes require that the neutral be connected to earth at the "service panel" only and at no other point within the building wiring system. Formally, the neutral is called the "grounded conductor"; as of the 2008 NEC, the terms "neutral conductor" and "neutral point" have been defined in the Code to conform to what had ...
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 ...
It is used as a grounding transformer, creating a missing neutral connection from an ungrounded 3-phase system to permit the grounding of that neutral to an earth reference point; to perform harmonic mitigation, as they can suppress triplet (3rd, 9th, 15th, 21st, etc.) harmonic currents; [2] to supply 3-phase power as an autotransformer ...