1. Earthing, or grounding, provides greater safety for human life, property, and equipment by providing an alternative path for faulty currents to flow safely into the earth.
2. There are two types of earthing: equipment earthing, which connects the metallic enclosures of electrical equipment to earth; and system earthing, which connects parts of the electrical power system like the neutral point to earth.
3. For stand-alone PV systems, there are three scenarios for equipment earthing: an ungrounded enclosure, an enclosure connected to the neutral wire, or a ground wire connected directly to the enclosure.
4. IMPORTANCE OF EARTHING
1.Earthing provides an greater safety for human life, property or equipment.
2.To limit spikes and surges from lighting strikers or other high-voltage condition on
PV.
3.Earthing provides an alternative path to faulty current to flow into the earth.
4. A human body can withstand 30mA for 25ms, and even depends on body of a person.
5. Grounding or Earthing
• The process of connecting the metallic frame (i.e. non-current carrying
part) of electrical equipment or some electrical part of the system (e.g.
neutral point in a star-connected system, one conductor of the secondary
of a transformer etc.) to earth (i.e. soil) is called grounding or Earthing.
Grounding or earthing may be classified as:
• Equipment grounding.
• System grounding.
8. Equipment Grounding
The process of connecting non-current-carrying metal parts (i.e. metallic enclosure)
of the electrical equipment to earth (i.e. soil) in such a way that in case of insulation
failure, the enclosure effectively remains at earth potential is called equipment
grounding.
(i) Ungrounded enclosure
(ii) enclosure connected to neutral wire
(iii) ground wire connected to enclosure.
There can be three scenarios:
16. System Grounding
The process of connecting some electrical part of the power system (e.g. neutral point of a star
connected system, one conductor of the secondary of a transformer etc.) to earth (i.e. soil) is called
system grounding
