Air switch and leakage switch function difference - Database & Sql Blog Articles

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It is generally recommended to install an air circuit breaker at the outlet end of the meter because the wiring length is usually longer. If the leakage current of a residual current device (RCD) increases, it might be due to the wiring itself. It's better to install the RCD before using the equipment. The main difference between an air circuit breaker and an RCD is that the air circuit breaker trips when the current exceeds its rated value, while the RCD trips if the current exceeds the rated value or if there is a leakage. These devices are typically used for home or office lighting to ensure human safety.

An air circuit breaker, commonly known as an air switch, is a low-voltage switching device with multiple protection functions. It can cut off the circuit under normal voltage and current conditions. It offers protection against short circuits, overcurrents, and other faults. Some models also include shunt control or under-voltage protection as optional features. This makes it suitable for handling various electrical faults such as overloads, short circuits, and low voltages.

The correct name for a leakage switch is a residual current circuit breaker (RCCB). It is essentially an air circuit breaker with an added leakage protection function. In addition to the basic protections of an air circuit breaker, it can quickly disconnect the circuit if a leakage occurs in the load, helping to prevent electric shocks and damage to equipment caused by faulty wiring.

However, a leakage switch cannot fully replace an air circuit breaker. While it offers more protection, frequent leakage events can lead to unnecessary power cuts, which may disrupt the normal operation of electrical devices. Therefore, it is often used in temporary construction sites or in socket circuits of industrial and residential buildings.

A leakage switch can be considered a type of air circuit breaker, as both use similar mechanical actions and arc extinction methods. However, the key difference lies in their purpose: leakage switches focus on protecting people from electric shocks. Their trip threshold is usually in the milliampere range. They detect residual currents—essentially the imbalance between the phase and neutral currents in the circuit. This allows them to respond quickly to ground faults and prevent direct contact shocks. In contrast, air circuit breakers only protect against overcurrents and short circuits.

Air circuit breakers are divided into two types: miniature circuit breakers (MCBs) and molded case circuit breakers (MCCBs). Both provide overload and short-circuit protection, but they differ in their short-circuit breaking capacity, which varies depending on the model and manufacturer. Leakage protection switches, on the other hand, are primarily designed for leakage protection. In residential settings, the typical leakage current setting is 30mA, calculated based on the resistance of the human body and the voltage during an electric shock. When a person gets shocked, some of the current flows through the body to the ground, and the RCD detects this imbalance and trips to protect the individual.

An air circuit breaker only trips due to overloads or short circuits, while a leakage switch includes a built-in leakage detection system that triggers a trip when a leakage current is detected. Some circuit breakers combine both functions. It’s important to note that a leakage switch protects against single-wire contact, but not when a person touches both the live and neutral wires simultaneously.

While an air circuit breaker will trip when the current exceeds the set limit, a leakage switch will disconnect the circuit when the leakage current surpasses the threshold. Some models offer both functionalities. Additionally, if the air circuit breaker is not energized, pressing the test button will still cause it to trip. However, a leakage switch will not trip if it is not powered.