Earthing
- In earthing body of the equipment is joined to the electrode of the earth pit through the earth wire. By earthing the body of the equipment is brought to the zero potential of the earth.
Grounding
- Many times grounding of the equipment is done instead of earthing .
- In this the necessary parts are joined by a wire but wire is not connected to the earth electrode.
- Due to this the joined parts come to the same potential but do not come to the zero potential as the common connection is not joined to the earth electrode.
- Grounding is employed in electronic devices and high voltage substations.
- Static electricity is produced in electronic equipments.
- Disturbances are caused in the operation of the equipment due to the accumulation of charge on the metal part.
- Due to grounding the static charges are given path and grounded parts come to the same potential.
- This is called the system Ground.
- In high voltage substations also static electric charges are produced.
- This charge can be earthed but as there is some resistance between different earthings and as these resistances as are not equal, static voltage is produced which may cause damage.
- So far this all the parts at zero potential are joined with a wire.
- This called ground wire.
- This wire is earthed at the two ends.
Bonding
- Many times static electric charges are produced due to friction between the two rotating parts which produces potential difference between these two parts.
- These two are joined by a flexible copper.
- This is called bonding.
What is Equipment earthing and System grounding in form of difference ?
Equipment Earthing
- In this the body of the equipment is connected from one or more points to the electrode buried in the earth.
- This is used to provide protection to the equipment and person.
- The equipment can operate without safety even if the earthing is not done.
- There is possibility of development of voltage on the body of the equipment at the time of earth fault.
- Cross section for the earthing conductor should be more as the short circuit current flows when fault occurs.
- Fuse or earth fault relay operates when fault occurs.
- Potential of the body of the equipment comes to the ground potential when earthing is done.
System grounding
- In this some parts of the system or equipment are joined with simple wire which may or may not be connected to the earth.
- System grounding is needed for proper working of the equipment.
- The equipment grounding is needed for proper working of the equipment.
- The equipment cannot work without grounding where it is necessary.
- In this Grounding all the connected parts come to the same electric potential.
- It is necessary to have greater area of cross section of the grounding wire as it is used to bring the connected parts to the same potential.
- This is not essential in grounding.
- As the connected all the parts are not joined to the earth, their potential are not joined to the earth, their potential does not become equal to the ground potential. However they remain to the same potential.
Similarities
- In both the methods the parts are brought to the equal potential.
- Conductor is required in both the system.