What is Grounding?
The term grounding is commonly used in the electrical industry to mean both “equipment grounding” and “system grounding”.
“Equipment grounding” means the connection of a non-current carrying conductive materials such as conduit, cable trays, junction boxes, enclosures and motor frames to earth ground.
“System grounding” means the connection of the neutral points of current carrying conductors such as the neutral point of a circuit, a transformer, rotating machinery, or a system, either solidly or with a current limiting device to earth ground.
Figure 1 illustrates the two types of grounding.
What is a Grounded System?
Grounded System is a system with at least one conductor or point (usually the middle wire or neutral point of transformer or generator windings) is intentionally grounded, either solidly or through an impedance. IEEE Standard 142-1991 1.2
What are the Different Types of System Grounding?
The types of system grounding normally used in industrial and commercial power systems are:
- Solid grounding
- Low resistance grounding
- High resistance grounding
- Ungrounded (IEEE Std 242-2001 8.2.1)
What is the Purpose of System Grounding?
System grounding, or the intentional connection of a phase or neutral conductor to earth, is for the purpose of controlling the voltage to earth, or ground, within predictable limits.
It also provides for a flow of current that will allow detection of an unwanted connection between system conductors and ground (a ground fault).
What is a Ground Fault?
A Ground Fault is an unwanted connection between the system conductors and ground.
|Title:||Ground Fault Protection Technical Guide – Converting undergrounded systems to high resistance grounding|
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