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Residual Current Circuit Breaker (Details and Operations)


Do you want a solution to protect the low-voltage circuit in case of any fault? The residual current circuit breaker is a solution to this problem. In this article, we’ll discuss the residual current circuit breaker, its purpose, and the benefits it can bring to you. So, let’s start:

What is a Residual Current Circuit Breaker (RCCB)?

In simpler words, a residual current circuit breaker (RCCB) is an electrical device. It protects the electrical device from electric shocks. Moreover, the RCCB monitors and controls the flow of electrical current in a circuit. It is also commonly known as a Ground Fault Circuit Interrupter (GFCI) or an Earth Leakage Circuit Breaker (ELCB) in other regions.

The RCCB works by controlling and monitoring the flow of current in a circuit. RCCB also compares the current—the flow of current while entering a device and the flow of current returning from it.

In a properly functioning electrical device, the current entering and the current coming back should be equal, and its balanced flow is controlled and monitored by RCCB.

But what happens when there is a fault? Maybe a leakage! The current returning from the circuit becomes unbalanced. Such a situation is dangerous, and RCCB detects this imbalance and takes action to control it.

How does it work?

Kirchhoff’s Current Law is the driving force behind this RCCB circuit. According to this law, the incoming current in any circuit should be equal to the outgoing current. In RCCB, whenever a difference in the incoming and outgoing current is recorded, the residual current switches off the entire circuit.

To manage the equality of flowing current, the circuit measures the current at both terminals every instant. Thus making it possible for the circuit to work.

Below is a breakdown of how RCCB works for a better understanding:

  • The RCCB continuously monitors the current that is entering the circuit and the current that is coming out of the circuit.
  • The RCCB compares the current in the live and neutral conductors, it makes sure the currents are equal.
  • If there is an imbalance, and the current leaving the circuit is higher than the current entering, the RCCB detects it immediately.
  • Once the RCCB detects the imbalance, the internal tripping mechanism is activated.
  • The activation of the internal tripping disconnects the power supply, and the RCCB prevents electric shocks and fire.

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Types of RCCB:

Two main types in the residual current circuit breaker exist, too.

These include a two-pole and 4-pole circuit.

2-pole circuit: In this circuit, there is a single life and only one neutral wire.

4-pole circuit: In this circuit, four slots are available for the connection in which you can connect three-phase wires and a neutral one.

The sensitivity of the RCCB circuit:

The RCCB circuit is highly-sensitive. It is designed to monitor 10mA of residual current. This is the amount of current that humans can bear with a prickling sensation. However, if the purpose of using this circuit is to prevent electric fire, it can resist up to 300mA as well, making the circuit resistance worthwhile.

Benefits of RCCB:

With this Residual Current Circuit Breaker, you can get the following benefits:

1. It provides real-time protection to the circuits, saving electronic gadgets from a severe problem.

2. Commercial buildings and industries use these circuits to limit the risk of electric shocks. 

3. Besides, it can help protect the high-cost machinery and parts as it disconnects the circuit in voltage fluctuations.

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Limitations of RCCB:

RCCB can work only with standard waveforms. In case of any unusual waveforms, this circuit will not work.

You might experience unwanted tripping even because of minor fluctuations that aren’t even dangerous for the machine or the people.

A current overload cannot be detected with this circuit. It only detects the difference between the live and neutral current.

Line-neutral shocks can still exist because the current at the terminals is the same as the line-neutral shocks.

Summing Up:

All these details about the Residual Current Circuit Breaker could have cleared your concept. If you are planning to use RCCB in any circuit, make sure to keep the circuit’s limitations in mind. So you can get the desired results.

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