2A Flashcards
What is grounding?
The conductive path between earth and grounded object.
What are the three main functions of grounding?
personnel safety, equipment protection, and electrical noise protection
How does grounding protect personnel?
By grounding electrical equipment, buildings, and large metal objects that could conduct dangerous currents. Grounding such items diverts dangerous currents to earth and activates protective devices (such as fuses and circuit breakers) that shut down the affected circuit.
How does grounding protect equipment?
By grounding power sources, equipment racks, building structures, and other conductive objects. This prevents transient voltages and currents from reaching levels that could damage equipment.
How is electrical noise reduced?
One method is reducing the voltage potential difference between equipment.
Another is connecting and thus lowering the resistance between the signal reference subsystem and the earth electrode subsystem.
Noise control may also require other measures such as shielding or filtering of local noise sources.
What is a facility ground system?
Provides a conductive path between the earth and the grounded facility
What are the three subsystems of the facility ground system?
Earth electrode subsystem, equipment fault protection subsystem, signal reference subsystem
What is the earth electrode subsystem?
Provides the connection between the earth and the other subsystems in the facility ground system.
What does a typical earth electrode subsystem consist of?
A network of buried conductors (earth electrodes) such as ground rods, metal straps, wires, tubes, grids, plates, sheets, water pipes, and well casings.
What is the equipment fault protection subsystem?
Protects personnel and equipment from voltages caused by faults in
electrical circuits.
The equipment fault protection subsystem is sometimes referred to as?
The safety ground
What is the signal reference subsystem?
Establishes a voltage reference for signal circuits and controls electrical noise and static in a facility.
What is a signal ground within a piece of equipment?
A bus bar or any conductor that serves as a reference plane
of the signal circuits within the equipment
What is a signal ground between pieces of equipment?
A grid or a network of wires, straps, grounded
equipment racks, and other conductors.
What is an equipotential plane?
A network that establishes a multipoint signal reference subsystem is to bond equipment cabinets, racks, conduits, ducts, bus bars, wires, and other conductors to a common interior metal sheet or grid. All
points in the network are at the same potential.
Also refers simply to the sheet or grid to which the other conductors are connected.
