Electric faults in circuits and buildings

Electric energy is used in homes and industries to perform various activities. For example, electricity in homes is used for lighting, cooking, charging mobile phones, and ironing clothes. When converted into mechanical energy, it can be used to operate machines such as milling machines. The amount of electricity consumed in homes varies depending on the uses. Thus, the amount of electricity used in homes may increase or decrease, depending on circumstances. Unexpected increase or decrease of current is called electricity fluctuation. Such fluctuations can produce electric faults in electric appliances or cause fire in buildings.

Increase of electric current

There is a maximum limit of current which can safely flow through circuits of electric devices or buildings. Increase of electric current is said to occur when it exceeds the limit specified for a circuit or building. Increase of electric current occurs due to an abrupt increase in source voltage or improper connections of circuits. Similar increase of electric current in electric devices can occur when there is short circuit. Increase of electric current may cause destructions such as burning of buildings and electric devices including refrigerators, electric irons, electric cookers, radios and television sets. Increase of electric current may also cause burning of electric wires in buildings and transformers. It may also cause injury and death to human beings. Thus, the electric circuit in a building gets damaged when electric current increases above a specific limit.

Decrease of electric current

Decrease of electric current is said to occur when it is below the limit specified for a circuit or building. Decrease of electric current in homes and industries may be caused by overloading of electric networks, decreased electric supply voltage or defective transformers. Decrease of electric current may also be caused by incorrect connections or overloading of an electric circuit which occurs when too many electric devices or appliances are connected to a single circuit. Decrease of electric current in homes lowers performance of appliances, for example dimming of the lighting system. Similarly, decrease of electric current may make appliances such as electric cookers, refrigerators or motors fail to operate. It can also damage electric stabilizers.

Protection of Electric Circuits and Appliances Against Current Fluctuations

Electric circuits and appliances are vulnerable to damage when there are fluctuations in electric current, such as an increase or decrease in the current. These fluctuations can cause electric devices to fail or get damaged. To prevent such damage, special devices are used to protect electric circuits, devices, and buildings. The devices that perform this function include

1. fuses
2. circuit breakers
3. earth wires.
4. electric stabilizers

Fuse

A fuse is a device used to protect electric circuits from damage caused by excessive current. The current flowing through a circuit has a specified limit, depending on the type of wire used in the circuit. Electric faults, such as short circuits or excessive current, can cause damage to electric devices connected to the circuit. A fuse consists of a thin electric conductor that allows only a specified amount of electric current to flow through it.

1. Function: When the current exceeds the rated value for normal operation, the fuse wire melts and breaks the circuit, preventing damage to connected devices.
2. Types: Fuses come in different ratings (e.g., 3A, 5A, 10A, 15A, 30A), depending on the amount of current the appliance requires.
3. Replacement: After a fuse melts, it must be replaced with a new fuse that has similar specifications.

Circuit Breaker

A circuit breaker is another device used to protect electric appliances from damage caused by excessive current or short circuits. It is commonly used in homes and industries.

1. Function: A circuit breaker receives electric current from the electric meter and contains a tripping switch. When the current does not exceed the specified value, the circuit breaker remains in the "ON" position. However, when there is an abrupt increase in current or a short circuit, the circuit breaker trips to the "OFF" position, creating an open circuit that stops the flow of current.
2. Operation: The tripping action prevents further flow of electricity to appliances, such as lights, electric cookers, and refrigerators.
3. Resetting: It is advisable to resolve the fault that caused the circuit breaker to trip before resetting it to resume normal operation.

Circuit breaker

Earth Wire

The earth wire is used to protect the user of electric appliances from electric shock due to faulty wiring in metallic electric devices, such as an electric iron or refrigerator. These devices have the potential to conduct leakage current.

1. Function: The earth wire protects the user from electric shocks by providing a safe path for leakage current to flow into the ground, rather than through the body of the user.
2. Earth Cable Setup: The earth cable has one end connected to the metallic casing of the appliance, and the other end connected to a copper rod buried in the earth. In the event of an electric fault, the leakage current will flow from the appliance's metallic casing through the earth cable to the ground, preventing the user from getting shocked.

Earth wire

Electric Stabilizers

Electric stabilizers are devices used to protect appliances like computers, radios, televisions, and refrigerators from the harmful effects of voltage fluctuations.

Function: They stabilize the voltage supplied to the appliance, preventing damage caused by increases or decreases in electric current.