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What is a Short Circuit? | Meaning and Definition
We often talk about short circuit in our daily life when there is burst in electric circuit. Have you ever think why this happen. In this article we will have a detailed discussion on short circuit.
A short circuit occurs when there is a low impedance connection between the two conductors supplying the circuit. As a result, the power supply consumes excessive current and voltage. The current will follow a “short” path, causing a short circuit.
Electricity chooses the path of least resistance. Copper is used in electrical wiring because it conducts electricity efficiently, but wiring materials such as wood and fiber are inefficient because they are electrically resistant. Steel and iron are also poor wiring materials. However, it is better than wood and fiber.
Under certain circumstances, such as a broken or loose power cord can leak current through the power cord. At this point, the current attempt to return to earth by a short route. However, this route carries certain risks, including the possibility of fatal electric shock, due to the current flowing through highly flammable materials.If the wire is loose, damaged, or faulty, current will always follow the path of least resistance, including through the body of the person touching the switch.
Short Circuit Current
A short circuit is the flow of current in the wrong or unintended path with little or no electrical resistance. It can cause severe damage, fire or even a small explosion. In fact, short circuits are the leading cause of building fires worldwide.When two or more out-of-phase conductors of a power element such as a power line or power transformer touch, some of the impedance of the circuit is consumed and a large current flows in the normal phase, and this current is called short-circuit current. Short-circuit current reduces the effect of impedance in a circuit as the current in the circuit increases.
Reasons of Short Circuit:
- Wires are gnawed by pests and vermin.
- If electrical cables come into contact with water or other liquids.
- Poor connection in the electrical wiring of the device.
- Old or damaged sockets, switches, lamps, appliances or other electrical equipment.
- Abnormal accumulation of current.
- Walls punctured with nails or screws come into contact with live power cables.
Types of Short Circuit
Basically two types of short circuit occur as given below.
- Normal Short Circuit
- Ground Fault Short Circuit
Let’s know more in detail about these 2 types of short circuit.
1. Normal Short Circuit
A normal short circuit occurs when a energized hot wire touches a neutral wire. As a result, the resistance quickly decreases and significant current flows in the other direction.
2. Ground Fault Short Circuit
A ground fault occurs when a live wire touches the grounded part of the system. Examples include a grounded metal wall box, an exposed drain wire, or an appliance ground.
Symptoms of an Electrical Short
1. Burnt Smell from Sockets and Burn Marks
If the outlet shows signs of burning or smells like something is burning, this could be a sign of a short circuit.This is often caused by an overloaded electrical circuit. , may pose a fire hazard.
2. Buzzing and Popping Sounds from Sockets
Another sign to look out for is if the outlet makes a buzzing or popping sound. This can also be caused by overloaded electrical circuits, which is of great concern.
3. Sparks from the Circuit
Another sign of an electrical short is sparks from an electrical outlet. Sparks indicate excessive current in the circuit and can be dangerous.
Precautions in the Event of an Electrical Short Circuit
- Look for signs of a defective socket. A damaged cord, loose junction box, or outlet that has been in use for more than 15 to 25 years can cause a short circuit.
- Short circuits can also be caused by bad wiring or cracks in the device. You must immediately take the necessary steps to repair or replace the faulty device.
- Using multiple outlets at the same time or overloading the plug may cause a fire or short circuit. A lightning strike can cause a dangerous short circuit due to the amount of electricity it carries. You should avoid using electricity during storms to avoid short circuits and surges.
Short Circuit Diagram
A simple short circuit diagram is shown below.
The diagram above shows what a simple circuit looks like under operating conditions. A screening circuit exists if current can bypass the device, as shown in the following figure.
In the first circuit, the current had to form a perfect loop and pass through a high impedance device. In the second case, electricity found a “shortcut” to bypass all devices. Due to the high power output of the power supply and wires with little resistance, currents can reach astronomically high values, causing circuits to overheat and fail. This can lead to fires or, at the very least, more frequent electrical circuit failures. The wire will char and the fuse will blow, “opening” the circuit as shown below.
No more current will flow, the current will drop to zero, and the wire will cool.