What factors are effect on the resistivity?

What factors are effect on the resistivity?

Then the factors which affect the resistance (R) of a conductor in ohms can be listed as:

• The resistivity (ρ) of the material from which the conductor is made.
• The total length (L) of the conductor.
• The cross-sectional area (A) of the conductor.
• The temperature of the conductor.

What is the maximum value for the earth resistance?

Ideally a ground should be of zero ohms resistance. There is not one standard ground resistance threshold that is recognized by all agencies. However, the NFPA and IEEE have recommended a ground resistance value of 5.0 ohms or less.

How do I test my house for grounding?

How to Tell If Your House Wiring Is Grounded

1. Look at the outlets in your home.
2. Insert the circuit tester’s red probe into the smaller outlet slot.
3. Insert the black probe into the larger slot in the outlet.
4. Look at the indicator light.
5. Repeat Steps 1 through 4 in all the outlets of your home.

How do I fix a grounding problem in my house?

One of the simplest grounding problems to fix is making sure that all ground connections are correct.

1. Shut off the main electrical power.
2. Find the grounding rod driven into the ground.
3. Check the ground connection clamp.
4. Check the ground wire running to the copper or galvanized water service inside the house.

What happens if your house isn’t grounded?

If there is no ground connection or a poor ground connection in the house, electricity could travel through your body to the ground. In this case you would end up becoming the ground connection – a condition that can lead to serious injury or also death.

Is the earthing properly done yes or no?

Answer. An ‘Earthing Circuit’ is provided in all household appliances to protect the user from fatal electric shock. The earthing wire in the appliance is connected to a power-point (wall socket) which in turn is connected to a Copper Rod located outside the building and sunk approximately one-meter in the ground.

What happens if the earth wire is not connected?

Without the earth wire, if a fault occurs and the live wire becomes loose, there is a danger that it will touch the case. The next person who uses the appliance could get electrocuted . The earth wire is therefore connected to the case and is attached to a metal plate or water pipe underground.

What Colour is the insulation that covers a live wire?

Brown

Is Red live or neutral?

Answered by Dave, Electrical Safety Expert The UK changed the standard wire colours in 2004: The live Red becomes Brown. The Neutral Black becomes Blue.

Is red and black wiring legal?

A red electrical wire was used to signify a live current. And green and yellow wires were earth wires. Both red and black electrical wires are now illegal and any outdated wires must be replaced by a qualified electrician.

Is Black Live and Red neutral?

Black (neutral) Red (live) Green and yellow (earth)

What color is the red wire?

Black or red wires always carry power from the service panel (breaker box) to your home’s devices. What are Red Wires? Red wires are usually used as secondary hot wires. Red wires are also hot and should be clearly marked to avoid the dangers of electrocution.

Is Red live in old wiring?

The earth wire will be green and yellow (or sometimes bare in old systems). The live wire is brown in new systems and red in old systems.