Metals grounding conductors

Offshore, the equipment and system ground conductors are connected to the facility s metal deck, usually by welding. The metal deck serves the function of the ground loop and is connected to ground by virtue of solid metal-to-metal contact with the platform jacket. 

Flexible cord approved for extra-hard service, flexible metal conduit, and liquidtight flexible conduit for limited flexibility. A suitable grounding conductor must be provided inside the flexible cord s outer jacket. Flexible conduit must be bonded with an external jumper or an approved internal system jumper external bonding jumpers are disallowed for flexible conduit exceeding six feet. Typical liquidtight and flexible cord connectors and an explosion-proof flexible connection are shown in Figure 17-23. 

Equipment grounding conductor Conductor used to connect the non-currentcarrying metal parts of equipment, raceways, and other enclosures to the system grounded conductor, the grounding electrode conductor, or both at the service equipment or at the source of a separately derived system... 

The problematic nature of the melting transition can be illustrated by comparison with other well-known first-order phase transitions, for instance the normal metal-(low T ) superconductor transition. The normal metal-superconductor and melting transitions have similar symptomatic definitions, the former being a loss of resistance to current flow, and the latter being a loss of resistance to shear. However, superconductivity can also be neatly described as a phonon-mediated (Cooper) pairing of electrons and condensation of Cooper pairs into a coherent ground state wave function. This mechanistic description of the normal metal-super-conductor transition has required considerable theoretical effort for its development, but nevertheless boils down to a simple statement, indicat-... 

Grounding by attaching the device enclosure to the machine with bolts or other approved means shall be considered satisfactory if all paint and dirt are removed from joint surfaces. Moving machine parts having metal-to-metal bearing surfaces shall not be considered as a grounding conductor. 

B) The noncurrent-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame. 

Methods of grounding equipment—(i) With circuit conductors. Noncurrent-carrying metal parts of fixed equipment, if required to be grounded by this subpart, shall be grounded by an equipment grounding conductor which is contained within the same raceway, cable, or cord, or runs with or encloses the circuit conductors. For DC circuits only, the equipment grounding conductor may be run separately from the circuit conductors. 

D) Metallic guards shall be grounded by the means of an equipment grounding conductor run within the power supply cord. 

Conductors shall also be so located or guarded as to protect them from physical damage. Multiconductor portable cable may supply mobile equipment. An equipment grounding conductor shall be run with circuit conductors inside the metal raceway or inside the multiconductor cable jacket. The equipment grounding conductor may be insulated or bare. 

The IEEE definition makes an important distinction between ground and earth. Earth refers to mother earth, and ground refers to the equipment grounding system, which includes equipment grounding conductors, metaUic raceways, cable armor, enclosures, cabinets, frames, building steel, and all other non-current-carrying metal parts of the electrical distribution system. 

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. 

Figure 14.6 shows a schematic illustration of the basic setup for electrospinning. It consists of three major components a high-voltage power supply, a spinnerette (a metallic syringe needle) and a collector (a grounded conductor). 

---