After listening the term ‘Short circuit‘ , A shiver get down the spine. Sparks, Fire, Destruction, Burning-melted materials just appear into the mind. Short circuit is real a dangerous phenomenon which should not be happen at any cost. This post is dedicated to shot circuit in which its reasons, its prevention steps & Applications are going to be discussed.
SHORT CIRCUIT
“The term Short Circuit represents shorting the potential difference carrying two nodes directly. Short circuit is rapid phenomenon Which leads to uncontrolled heavy current flows in undefined direction.“
Short circuit get happened when potential(phase/positive) get directly connected to neutral/negative /earth/phase without any type of load in between. The short circuit current can be multiple times the rated capacity of the system.
This heavy current continuously flows through the circuit until it get interrupted. Meanwhile; Due to excessive high current; Temperature of that particular section rises rapidly & burning get started. Short circuit produces excessive ampere loading on backend circuit, If not prevented earlier this will lead to the damage of entire circuit.
A GIF shows the short circuit phenomenon below. In which single phase supply is connected across the load though a switch. Due to some circumstances phase wire get break & fall down on neutral wire Which leads to short circuit.
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REASONS OF SHORT CIRCUIT
There are multiple reasons of short circuit. Which are discussed below one by one:
This thing happened When :
- Winding, cable or circuit get overheated.
- Some sort of conductive material get spread across the supply terminals.
- When circuitry get damaged due to the strike from external material.
REASON 2. Short Circuit also get happened when applied voltage is much; much larger than the rated capacity of the system.
For Example :
- Connecting 24VDC rated system with 240VAC.
- In 3 phase+ Neutral distribution system, When neutral node for single phase system get damaged which results double phase appear across the single phase load.
REASON 3. When one of the components of the circuit get damaged internally.REASON4. Improper load distribution. Such as light cable or wires for heavy loads.REASON5. Improper take care & maintenance of Electrical loads.
HOW TO PREVENT SHORT CIRCUIT
Short circuit current can rise multiple times the rated capacity of the system. If not get interrupted; It can damage the conductors through which it is flowing or in worst cases; The energy source can also be get damaged.
The chances of short circuit are always there even if the system’s quality is superior. But Short circuit can be interrupted by breaking its closed loop line current. There are multiple components available for short circuit protection which isolate the rest of the healthy circuit in fault conditions. All these components been discussed one by one next !
Fuse
Fuse is two terminals components through which load current flows. Fuse contains a thin wire specially designed for particular current rating. Whenever current exceeds the capacity of the fuse, Fuse get blown out. Fuse actually follows inverse time characteristics Which means higher the fault current, lower will be the blown out time. Fuse can be used only for once, Once it get blown out; it needed to be replaced.
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Circuit breakers
Circuit breakers are type of electromechanical arrangement. In normal condition, It connects the its two terminals. In fault conditions, Arrangement inside the breaker produces the trip signal & contact get break off.
Unlike fuses; Circuit breakers can be reset again & can be used multiple times after the trip operations.
For detailed operation of circuit breaker you can go through our another post Working of Circuit Breaker.
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Thermal Overload Relays
Thermal Overload Relays are specially designed for motor protections which can easily be connected across the contactor. These relays works on same phenomenon as Circuit breaker do.
For more details about the relays, You can go through our another post Thermal Overload Relay
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APPLICATIONS OF SHORT CIRCUIT
After getting the things about the short circuit; It is real awkward to know that there are applications which are based on Short Circuit. But in real; there are many applications which are based on this phenomenon Such as Welding machines, Electrical Insect killers & Surge Arresters.
Welding Machines
A basic electrical welding machine is a type AC/DC power source whose output’s voltage been reduced up to a particular extent. Such that a heavy current get available at output side. Through the mechanism of short circuit, The heavy current is used to weld the metals & joint them together.
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Insect/Fly killers
Electrical insect killers contains rails of high voltages. Two nearby rails are having a opposite polarities which are having a high potential difference.
Due to blue attractive light, flies get attracted towards the lights then they get attached to the rail & “Boom”.
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Surge Arrester
Lightning or thunderstorm can generate the voltage spikes in power distribution system. In along, Chances of voltage surges from switching Or discharges are always there. These high spikes & surges can damage the whole system. For protection from these voltage surges; Surge arresters been employed which works on the principle of short circuit !
Normally, the arresters are two terminal devices. One of the terminal side is connected with potential while another side of the terminal is connected with Earthing. Whenever high voltage spike appear across it, Surges arrester discharges the potential towards the Earthing.
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SUM UP
- A short circuit occurs when a direct connection get formed between potential carrying nodes, leading to a surge of current that can cause severe overheating and potential damage.
- Common causes include damaged insulation, excessive applied voltage, and faulty components.
- Preventative measures like fuses, circuit breakers, and thermal overload relays help protect circuits from short circuits.
- Interestingly, short circuits also have practical applications, such as in welding machines, insect killers, and surge arresters, where controlled excess current is beneficial.
- It is crucial to manage and interrupt short circuits to maintain system integrity and safety.
Hope, You like the post. If you have any doubt, Suggestion or query please do comments !