Bare conductors

Ground grid — System of interconnected bare conductors arranged in a pattern over a specified area and buried below the surface of the earth. 

Accidents are frequent when a person is electrocuted because of lack of care near the energized bare conductor, the construction area, rooftops, or TV antennas, or working on live high-voltage lines. 

First, instead of passing air through the core tube, a bare conductor wire is pulled through the die entering the core tube inlet and exiting the die pin. 

Size Area Circular Diameter ofSoUd Rubber Insulation Varnished Cambric Insulation Other Insulations and Bare Conductors Size Area Circular Diameter of Solid Rubber Insulation Varnished Cambric Insulation Other Insulations and Bare Conductors... 

There was a significant gap between the highest measurable recovery current (/mr) and the lowest measurable propagation current (/mp). This was —0.23/mr for the solder-filled cable, 0.33/mr for the insulated conductor, and —0.35/mr for the bare conductor. The behavior of the propagation velocity between these current values cannot be determined experimentally. 

The crosshead die is also used for wire coating. In wire coating, a conductor passes through the hollow center of the core tube and becomes coated with polymer melt close to the die exit. The conductor may be a bare conductor or it may already have been coated with one or more layers of polymer. In wire coating, one distinguishes between high-pressure extrusion and low-pressure extrusion see Fig. 9.19. 

Fig. 1.2 An early lead connector (Elema-Schonander). The distal insulation was stripped and bare conductor inserted into the pulse generator receiving port and secured with a small setscrew. The area was insulated with an O-ring against the pulse generator, a piece of T-tubing to cover the conductor and a plastic cap. (Permission for use St Jude.)...

Cables in need of repair shall not be used. When a cable, other than the cable lead referred to in paragraph (b)(2) of this section, becomes worn to the extent of exposing bare conductors, the portion thus exposed shall be protected by means of rubber and friction tape or other equivalent insulation. 

The size of the bare conductor for each tower radial (or for an interconnecting wire) will vary, depending on soil conditions. On rock, a bare no. 1/0 or larger wire is recommended. Flat, solid-copper strap would be better, but maybe blown or ripped if not covered with soil. If some amount of soil is available, no. 6 cable should be sufficient. Make the interconnecting radial wires continuous, and bury them as deep as possible however, the first 6 to 10 in. will have the most benefit. Going below 18 in. will not be cost-effective, unless in a dry, sandy soil where the water table can be reached and ground-rod penetration is shallow. If only a small amount of soil exists, use it to cover the radials to the extent possible. It is more important to cover radials in the area near the tower than at greater distances. If, however, soil exists only at the outer distances and cannot be transported to the inner locations, use the soil to cover the outer portions of the radials. 

Isolated ground (IG) receptacles, which are a version of single-point grounding, are permitted by the NEC. Proper appHcation of IG receptacles is very important. They must be used with an insulated equipment grounding conductor, not a bare conductor. Also, only metallic conduit should be used. 

It is considered an advantage to earth ar r metal framework of a building, in order that ar r bare conductors of stray electrical cmrent can be diverted to earth. If a metal frame was not earthed and became active, ar r person in direct contact with the frame and earth could be electrocuted. The earthed frame means that the fault to the frame would immediately be earthed. 

Never use bare conductors, damaged regvdators, torches, electrode holders, or other defective equipment. 

Appropriate surface treatments for the bare conductors after the coverlay construction should be chosen according to termination technologies. Several examples are listed in Table 62.4. Details are explained in Chap. 64. 

Because the flying leads are basically bare conductors, suitable surface treatments should be conducted according to termination technologies. 

There are several choices of places to bnild micro bnmps on flexible circuits, as described in Chap. 64 (see Sec. 64.3.8). The same processes nsed to build ball grid arrays on rigid circuit boards are appropriate for flexible circuits with flexible photo-imageable solder mask. It is possible to build micro bumps on bare conductors using plating masks. Many micro bumps are built on fine flying leads without solder masks. A valuable construction of a flexible circuit is micro bumps built on the other side of the circuit through the dielectric layer.This can provide a reliable micro bump array because of the stable construction. 

A common example of the technique in factory environments is the bare conductors running at height along a wall, which are used to provide power to an overhead travelling crane the crane has power pick-offs that run along the conductors as the crane moves, to provide power to the drive motors. This technique is satisfactory so long as there is no easy access to the bare conductors from the crane structure or, for example, from ladders placed up against the wall. 

Where a formal permit to work procedure is not used, the responsible person should carry out a risk assessment to devise a procedure that will ensure safety. In the case of the crane painters previously mentioned, for example, they should be told them that they should not start work in the vicinity of the bare conductors until the isolator has been locked off, the conductors have been tested to ensure that they are dead, and they have been given permission to proceed. When the work is finished the circuits should not be re-energised until the painters have been withdrawn from the work area. 

Damages or worn cables exposing bare conductors should immediately be removed from service or repaired with rubber, plastic, or friction tape, equivalent in insulation to the original cable covering. 

Ametani, A., M. Nayel, S. Sekioka, and T. Sonoda. 2002. Basic investigation of wave propagation characteristics on an underground bare conductor. Proceedings ofICEE 2002, Jeju, Korea 2141-2146. 

Shock — Electrical shock is a sudden and accidental stimrdation of the body s nervous system by an electrical current. Look for bare conductors, insulation failures, buildup of static electricity, and faulty electrical equipment. 

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