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Intentional electrical connection to a reference conducting plane, which may be earth, but which more generally consists of a specific array of interconnected electrical conductors referred to as the grounding conductor.


Intentional electrical connections to a reference conducting plane, which may be earth (hence the term ground), but which more generally consists of a specific array of interconnected electrical conductors, referred to as the grounding conductor. The symbol which denotes a connection to the grounding conductor is three parallel horizontal lines, each of the lower two being shorter than the one above it (Fig. 1). The electric system of an airplane or ship observes specific grounding practices with prescribed points of grounding, but no connection to earth is involved. A connection to such a reference grounding conductor which is independent of earth is denoted by use of the symbol shown in Fig. 2.

The subject of grounding may be conveniently divided into two categories: system grounding and equipment grounding. System grounding relates to a grounding connection from the electric power system conductors for the purpose of securing superior performance qualities in the electrical system. Equipment grounding relates to a grounding connection from the various electric-machine frames, equipment housings, metal raceways containing energized electrical conductors, and closely adjacent conducting structures judged to be vulnerable to contact by an energized conductor. The purpose of such equipment grounding is to avoid environmental hazards such as electric shock to area occupants, fire ignition hazard to the building or contents, and sparking or arcing between building interior metallic members which may be in loose contact with one another. The design of outdoor open-type installations presents special problems.

Installations in which earth is used as a reference ground plane present special problems. To design an earth “floor surface” for an outdoor open-type substation which will be free of dangerous electric shock voltage exposure to persons around the station is a difficult task.


i. Declaring a pilot or an aircraft unfit to fly by the competent authority.
ii. Connecting a conductor to a ground or earth circuit.
References in periodicals archive ?
Relations between the obtained sums should correspond to the relations of potential groundings.
According to the results (Tables 1 and 2) on the Route Number Two, the expected number of potential groundings is 2.
The model proposed in this paper complements the existing models of calculation of potential number of groundings and introduces into calculation the influence of coastline parallel to the ship course, allowing the navigational routes to be ranked according to spatial distribution of dangers.
I)]--expected number of category I grounding events over a unit of time (because of the course overlapping with a danger); [P.
II)]--expected number of category II grounding events in a unit of time, as a function of the number and position of the turning points; [a.
III grounding events over a unit of time, as a result of taking evasive action near the obstacle; [P'.
4, for selected examples, one can define critical distances within which the number of potential grounding begins to increase very rapidly.
Accordingly, for the routes where navigation requires a state of maneuvering, comparison of routes should be in accordance with the actual number of grounding, i.
The goal is to find a safer route, considering the possibility of grounding.
However, this does not diminish the significance of the proposed model because the model assesses the risk of grounding on at a fundamental level.
GRACAT: software for grounding and collision risk analysis, Marine Structures 15(4-5): 383-401.
Together with analysis of the damage which can develop during grounding, it is relevant to consider the residual strength and the stability of the ship in the post-accident condition.