What is the cause of resistance?
Resistance is caused in a conductor by the free electrons. These free electrons collide with each other and with the ions and atoms that oppose their free movement. This obstruction is known as resistance.
Does temperature increase resistance?
As electrons move through a metal conductor, some collide with atoms, other electrons or impurities. These collisions cause resistance and generate heat. Heating the metal conductor causes atoms to vibrate more, which in turn makes it more difficult for the electrons to flow, increasing resistance.
What is the difference between resistance and resistivity?
Resistance is the physical property of a substance because of which it opposes the flow of current i.e. electrons. Resistivity is the physical property of a particular substance which is having particular dimensions. Resistivity is only proportional to the nature and temperature of the particular material.
What are the reasons for the increase in earthing resistance?
Earth Potential Rise (EPR) is caused by electrical faults that occur at electrical substations, power plants, or high-voltage transmission lines. Short-circuit current flows through the plant structure and equipment and into the grounding electrode.
Which type of earthing is best?
Plate earthing
Which type of earthing is cheapest?
1. Pipe earthing. Pipe earthing is best form of earthing. It is cheap in system of earthing a GI pipe of 38mm diameter and 2 meters length is embedded vertically in ground to work as earth electrod, but depth depends on soil conditions.
What happens if earthing is not proper?
If the house is not earthed, people could get electrocuted. Without an earth connection, the safety switches will not work and an electrical fault could cause a house or appliances to become ‘live’ as the current flows to earth.
How do I check my house for earthing problems?
Take a light bulb holder, connected with two wires i.e., for positive and negative terminals of the bulb. Now insert one of the wires in phase and the other in neutral. The bulb glows indicating the power supply. Take out the wire from neutral and insert it into the Earth’s hole.
Is earthing dangerous?
The earth’s surface has a negative electric charge, and when it comes in contact with human tissue, there is an equalization. The body can take on extra electrons and build up a static electric charge. This is called the Earthing hypothesis. This could cause a potentially dangerous electrical shock.