Residual Current Circuit Breakers (RCCB)

Circuit breakers are products designed to protect from damage caused by excessive current as a result of fault that may occur in the system.

What is a Residual Current Circuit Breaker (RCCB)?

The Function of a Residual Current Circuit Breaker is to detect leakage current that may occur in the system and protect people and installations by breaking the circuit within milliseconds.

Residual Current Circuit Breaker iID, 4P, 63A, 30mA, Tip A
Residual Current Circuit Breaker iID, 4P, 63A, 30mA, Tip A

The Working Principle of Residual Current Circuit Breaker (RCCB)

Residual Current Circuit Breaker performs the protection operation based on the principle of equality of the incoming current and the outgoing current ( Kirchhooff’s Law).

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The toroid current transformer in the residual current circuit breaker continuously measures the incoming and outgoing currents. If the incoming current and the outgoing current are equal, then everything is considered normal. In case of a leakage detection, a current imbalance occurs on the toroid, as a result, the toroid transmits this information to the residual current circuit breaker and opens the main contacts.

This is how RCD protects from electrocution.
This is how RCD protects from electrocution.
ACSensitive to residual sinusoidal alternating current only
ASensitive to residual alternating current and/or pulsating direct current
BProvide protection of alternating residual sinusoidal current up to 1000Hz, pulsating direct current and smooth direct residual currents.
FProvide protection for circuit using single phased variable speed drivers could be used.

Residual Current Circuit Breaker (RCCB) Vulnerability

A human being can withstand an electrical discharge of 30 milliamps. Although up to 10 mA may cause a prickling feeling, 10 mA and beyond may cause muscle spasm and respiration paralysis at roughly 30 mA. Manufacturers consequently build RCCBs to detect even the tiniest variations in residue power.

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Residual Current Circuit Breaker (RCCB) Selection

Proper selection and application of an RCCB is one of the simplest, cost-effective, safe and reliable options for protecting human and electrical equipment.

There are 4 main criteria in the selection of RCCB;

  • Number of Poles: Residual current circuit breaker (RCCB) has 2 and 4 poles. 2-pole residual current circuit breaker are used in single-phase distribution systems and 4-pole residual current relays are used in three-phase systems.
  • Sensitivity: Residual current circuit breaker (RCCB) has products with sensitivity between 10mA-500mA. Residual current circuit breaker with 30mA sensitivity for protecting human life and 300mA sensitivity for fire protection are used as standard.
  • Nominal Current Value: Residual current circuit breaker does not provide any thermal or magnetic protection. Residual current circuit breaker to be selected should be selected according to the nominal current allowed by the previous thermal magnetic protection circuit breaker.
  • Type: Residual current relays are produced in 3 types;

4.1- Residual current circuit breakers (RCCB): It cuts the circuit in case of a leakage current to the ground. Residual current circuit breakers cannot detect overloads and short circuits and do not open the circuit in these cases, so a fuse is needed to protect the circuit.

4.2- Residual current circuit breakers with overload protection (RCBO): This type of residual current devices are designed to be a miniature fuse in their structure and therefore an additional fuse is not needed.

4.3- Earth leakage relays (CBR): This type of residual current device is produced to meet industrial needs. They are suitable for three-phase systems and high-value currents. earth leakage relay works in such a way that the switch cuts the circuit when earth leakage occurs.

VEKMAR supplies all these range of RCCBs in stock quantities as official distributor of Schneider Electric, Eaton and LS Electric. We can help you for RCCB equipment for your projects with our expert engineering team.

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