Principle behind RCCB
RCCB works on the principle of Kirchhoff’s law, which states that the incoming current must be equal to the outgoing current in a circuit. RCCB thus compares the difference in current values between live and neutral wires. Ideally, the current flowing to the circuit from the live wire should be the same as that flowing through the neutral wire. In case of a fault, the current from the neutral wire is reduced, the differential between the two known as Residual Current. On spotting a Residual Current, the RCCB is triggered to trip off the circuit.
A test circuit included with the Residual Current device ensures that the reliability of RCCB is tested. When the test button is pushed, the current starts to flow through the test circuit. As it creates an imbalance on the neutral coil of the device, the RCCB trips and supply is disconnected thereby checking RCCB’s reliability.
Benefits of RCCB
Provides protection against earth fault as well as any leakage current
Automatically disconnects the circuit when the rated sensitivity is exceeded
Offers possibility of dual termination both for cable and busbar connections
Offers protection against voltage fluctuation as it includes a filtering device that guards against transient voltage levels.
Moulded Case Circuit Breaker is an electromechanical device which protects a circuit from overcurrent and short circuit. It provides overcurrent and short circuit protection for circuits ranging from 63 Amps up to 3000 Amps.
The primary function of an MCCB is to provide a means to manually open a circuit and automatically open a circuit under overload or short circuit conditions. The overcurrent, in an electrical circuit, may result from short circuit, overload or faulty design.
It is generally installed on the secondary side of transformer stations (main switch or for protecting individual branches). In industry, we can use it in switchgear or for protecting the motors as well we have big requirements in shipbuilding. For building applications, you can find it as the main protection switch.
The Molded Case Circuit Breaker is a specific type of circuit breaker.
NEMA defines Molded Case Circuit Breaker as devices designed to open or close a circuit by nonautomatic means and to open the circuit automatically on a predetermined overcurrent without damage to itself when properly applied within its rating.
The term “molded case” simply refers to the construction of the circuit breaker and refers to the fact that the circuit breaker is an assembled unit in a supporting housing of insulating material.
MCCB vs Fuse
MCCB is an alternative to a fuse since it does not require replacement once an overload is detected.
Unlike a fuse, an MCCB can be easily reset after a fault and offers improved operational safety and convenience without incurring the operating cost.
Essentially, circuit breaker is lockdowns but for a limited amount of time. They are designed to break the chain of infection, and bring the infection rate down. It’s hoped that circuit breakers will help to reduce pressure on health services as hospitalizations due to Covid-19 rise.
This is crucial for the U.K., which has the third-highest number of coronavirus cases in Europe, with its tally now standing at just over 744,000 cases with 43,816 fatalities, according to data from Johns Hopkins University. It is currently battling a dramatic second wave of infections, like the rest of Europe, particularly in northern England.
On Monday, 18,804 new daily infections were reported, up from 16,982 on Sunday. The seven-day average number of cases on Oct. 16 was 17,649, according to government data, compared to 14,588 a week before.
Scientists advising the government seem to favor circuit breakers, as does the opposition Labour Party, with both encouraging the government to implement a mini-lockdown.
