The Ultimate Guide to Residual Current Circuit Breaker (RCCB)

An RCCB (Residual Current Circuit Breaker) is used as a critical safety measure when it comes to electric circuit security.

RCCB, circuit breaker
An RCCB (Residual Current Circuit Breaker) is used as a critical safety measure when it comes to electric circuit security. (Image: Balurbala / CC BY-SA (

Although electricity has gradually become an essential component of our lives, the fact is still the same that it comes with its dangers to life and property. Given that the two main risks associated with electricity are electrocution and fire, one cannot afford to be careless when it comes to insulating equipment. That is when a Residual Current Circuit Breaker (RCCB) comes into the picture.

An RCCB (Residual Current Circuit Breaker) is used as a critical safety measure when it comes to electric circuit security. It is a current detecting system, which can calculate and disconnect the circuit automatically if a fault occurs in the connected circuit or the current exceeds the sensitivity level.

In cases of a sudden earth fault, RCCB is especially helpful in protecting a person from the risk of electrical shocks as well as electrocution and fires. RCCB 's presence guarantees that the circuit can pass instantly in such situations, thereby shielding the individual from an electrical shock.

There are two types of RCCB:

  • 2 Pole RCCB: This is used for single-phase supply connections that only has a live wire and a neutral wire.
  • 4 Pole RCCB: This is used when attaching a three-phase supply.

What is the Principle Behind RCCB?

RCCB operates on the Kirchhoff law theory, which states that the incoming current in a circuit must be equal to the outgoing current. Therefore, RCCB contrasts the difference between live and neutral wires in current values. Ideally, the current from the live wire flowing to the circuit should be the same as that which flows through the neutral wire. The current from the neutral wire is decreased in case of any fault, and the difference between the two known as Residual Current. The RCCB is caused to trip off the circuit when detecting a Residual Current.

A test circuit included with the system Residual Current make sure that the reliability of RCCB is checked. When you press the test button, the current will begin to flow through the test circuit. As it produces an imbalance on the device's neutral coil, the RCCB trips and supply are disconnected, thus proving the reliability of RCCB.

What Are the Benefits of RCCB?

Here, we have mentioned the benefits of a Residual Current Circuit Breaker (RCCB):

  • Offers protection from earth faults and any leakage current
  • Turns off the circuit automatically when the measured sensitivity is exceeded
  • Provides dual termination option for both cable and busbar connections
  • Provides protection against voltage fluctuation, as it includes a filtering system that protects against transient voltage.

Sensitivity of RCCB

A human being can withstand an electric shock for up to a magnitude of 30 mA. Although a prickling sensation can only elicit up to 10 mA, anything beyond 10 mA can lead to muscle contraction, leading to a respiratory paralysis of about 30mA. Therefore, RCCBs are configured to search for minor residual current shifts. RCCBs are often used for monitoring higher changes in residual current of up to 300mA in cases where fire safety is required.

There are RCCB's like Acti 9 xID and ID 125 that offer nominal current up to 125A, along with 30 mA sensitivity to have additional protection against direct contact. Not only this, but it also has 100, 300, 500 mA sensitivities, which provide further protection against fire and indirect contact (following IEC 364).

Therefore, RCCB is exceptionally critical in providing circuit safety in real-time. Its significance cannot be diminished in industries and high voltage commercial establishments as there is always the possibility of shocks and accidental deaths because of it.

Brands are selling a state-of-the-art RCCB product suitable for retail, residential, and commercial use. So, research about different power management products and consult a professional to buy the best one available.



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