Key Takeaways
- Short circuit: A short circuit occurs when a low-resistance path is formed between two conductors, causing a sudden increase in current flow. It is characterized by a path of low resistance, high current flow, and a rapid response from protective devices to prevent damage.
- Overload: An overload happens when the current drawn by devices exceeds the circuit’s designed capacity over a sustained period. It is characterized by excessive current draw, a gradual response that can lead to overheating. It occurs when too many devices are connected or a device draws more current than expected.
- Differences: Short circuits result from a low-resistance path and cause a sudden surge in current, while overloads occur when the current drawn exceeds the circuit’s capacity over time. Short circuits trigger rapid protective device response, whereas overloads may persist without immediate interruption. Short circuits pose a higher risk of fire hazards, while overloads can cause damage due to excessive heating over an extended period.
What is a Short Circuit?
An electric circuit that allows current to flow through a path from the circuit with minimum resistance is known as a short circuit. The electric circuit is short in resistance, and the circuit and equipment get damaged.
An electric circuit consists of conductors and insulators. Conductors are the ones that conduct electricity, and insulators are the ones that resist electricity. Both components are crucial to balance out the conductivity and the insulation of the current in a circuit.
When two adjacent wires in an electric circuit come in contact with each other, and the insulation factor reduces or breaks down, the circuit becomes short. The entire power system is damaged, leading to power shortages in certain areas.
When a short circuit occurs, the magnitude of the current flowing in the power system gets multiplied by the pre-existing amount of current. The fault point is the point where the short circuit occurs. During a short circuit, the voltage diminishes to zero at the fault point, giving the current the maximum flow possible.
Excessive heat is generated with excessive current flow in the power system, which, if not controlled, can lead to electrical fires or explosions.
What is Overload?
An overload in an electric power system is the condition when the voltage goes down to the minimum value, and the current is overloaded or superimposed at a certain point. In simpler words, overloading is the maximum or current imposed on the power system more than the regular load.
The voltage is dropped to the minimum possible value but does not go to zero. If we connect multiple devices to a single circuit, then a large number of current flows through a single outlet, which overloads it causing the fuse to blow off. The suitable value of the load is lesser than the value causing overload to the system.
Suppose various high-rated electrical appliances, like ovens, microwaves, refrigerators, air conditioners, etc., are connected to a single outlet. In that case, the current flowing through the system is much higher than the current allowed. If more current is generated, the wires get extremely heated and melt. Overloading can cause fire due to that.
As preventive measures, one should not connect multiple devices at once, avoid using faulty devices, and the devices should be within the range of the safe limit that the electric circuit can tolerate; a series connection of the electric fuse can also be implemented.
Difference Between Short Circuit and Overload
- There is contact between two wires during a short circuit; conversely, no contact occurs in overloading.
- A short circuit is comparatively more dangerous than overloading.
- The potential difference during a short circuit drops to zero; however, the potential difference becomes minimum but does not drop to zero during overloading.
- A short circuit occurs rarely; however, overloading occurs frequently.
- A short circuit occurs due to low resistivity or natural causes; on the other hand, overloading is frequently caused due to mechanical faults or connecting multiple high-power devices to a single socket.
- Reduction of the voltage applied through various devices is a factor causing overloading; on the other hand, this is not the factor responsible for a short circuit.
Comparison Between Short Circuit and Overload
| Parameters Of Comparison | Short Circuit | Overload |
|---|---|---|
| Detection | Difficult | Easy |
| Occurrence | Rare | Frequent |
| Danger | More | Less |
| Potential difference | Zero | Minimum but not zero |
| Preventive measures | MPR relays, magnetic relays | Thermal relays |
- https://ieeexplore.ieee.org/abstract/document/7055885/
- https://www.koreascience.or.kr/article/JAKO200706414511605.page
Last Updated : 13 July, 2023
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.
