Nov 2, 2016 at 10:24 am #651
Please explain the difference between MCB, MCCB, ELCB and RCCB and their respective applications.
Also, I have heard about RCBO and RCD. What are they? Is RCBO and RCD similar in principle?Nov 7, 2016 at 10:17 pm #661votes +1
Kiran DawareKeymaster25 votesPoints: 247
Difference between MCB, MCCB, ELCB, RCCB
MCB (Miniature Circuit Breaker)
MCB is commonly used in low voltage electrical network, such as homes, for overcurrent protection. MCB automatically disconnects the network in abnormal conditions such as overload or faults. MCBs are generally used for operating currents below 63 Amps. In some cases, MCBs can be used up to 100 Amps also.
MCCB (Moulded Case Circuit Breaker)
MCCBs also offer protection from short circuits and overcurrents (overloads), but they operate for higher current levels than MCBs. MCCBs are commonly used for operating current between 63 Amps to 800 Amps. They are also available for operating currents as low as 25 A and as high as 1000A.
ELCB (Earth Leakage Circuit Breaker)
As the name suggests, an ELCB is used to detect a current flowing through the earth (ground wire). If ground current exceeding few milliamps is dected, the ELCB trips (disconnects) the circuit from the supply. ELCB is also known as Ground Fault Circuit Interrupter (GFCI)
RCCB (Residual Current Circuit Breaker)
RCCB trips the circuit when any mismatch between phase current and neutral current is detected. That means, RCCB operates for earth faults (when the phase wires gets in contact with the ground). Most widely used RCCBs are 30 mA and 100 mA device, which means they will trip the circuit if the difference between phase current and neutral current is more than 30 mA and 100 mA respectively. Most of the RCCBs are designed to trip the circuit within 30 milliseconds when a mismatch is detected. RCCBs are extremely effective for preventing electric shock hazards. For example, if someone touches the phase wire accidently, a part of current will flow through the human body and hence causing mismatch between phase current and neutral current. In this case, the RCCB will trip the circuit almost instantly and thus preventing the shock hazard. RCCBs are also called as Residual Current Device (RCD).
RCBO (Residual current Circuit Breaker with Overcurrent protection)
RCBO is basically a combination of MCB an RCCB in one device. RCBO provides overload protection as well as earth fault protection.