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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 ?
EPRI has already begun analyzing ways to minimize magnetic fields associated with electrical grounding systems.
Finally, connect the 155-ft grounding wire to the mounting bracket bolt of the #1 floodlight.
Use tie wraps, NSN 5975-00-074-2072, to secure the grounding wire to the power cable.
First, if the system you are grounding needs to move and then set up again at a moment's notice.
For the 9-ft, 1-in thick ground rod, you'll need clamp, NSN 5975-01-034-8882, to hold the grounding strap to the rod.
To set up the SWGS, lay the grounding cable on the ground around the van with one end near the power entrance panel.
Drive the grounding pegs following the route of the cable at 5-ft intervals and attach the grounding cable.
Inside the van, part of your grounding system is having each piece of communications equipment bonded to the shelf it sits on.