MCB, MCCB, RCCB, ELCB-What do these circuit breakers do and how different they are

Circuit Breakers are crucial for human and equipment protection. This blog explains their importance and difference in the simplest way possible.

Imagine you have planned a birthday surprise for your best friend. You have got a custom cake, the finest of the wine, the favorite entrée menu, and a whole bunch of common friends invited. You escort the unassuming celebrant and switch on the lights. But what — the whole house gets in a power failure. Because probably oven, grinder, and room heating unit all were left on. Switching on of all the lights got the load too large and tripped MCB. It sure dampens the surprise but keeps your house safe from accidental fire hazards. Circuit breakers are clever devices that protect you along with homes, offices, and industrial setups.

Most people have heard about circuit breakers. Many of you would have a vague idea that these devices have something to do with circuit protection. Barring people who work day-in day-out with these products—not many of us know what these crucial electrical devices do.

As you might have noticed the acronyms end with ‘CB’ –meaning circuit breakers. MCB, MCCB, RCCB, and ELCB are all circuit breakers but they serve an exclusive specific purpose. Before we dive a bit deeper and understand differences, let’s begin with understanding their basic functions.

MCB

MCB stands for Miniature Circuit Breaker. It is the most familiar circuit breaker of them all, because of its ubiquitous presence in households. It automatically switches OFF electrical circuit in conditions such as overload and short circuit. But this is what fuse does? Isn’t it? Well, a fuse may sense unusual situations in the electrical network but needs to be replaced while MCB can be reset.

MCB protects electric wires and appliances from overcurrent, essentially preventing fire or electrical hazards. MCB restores the supply faster and therefore is the preferred choice for overload and short circuit protection. 

MCCB

MCCB, another device in the CB family, is the Molded Case Circuit Breaker. It comes into the picture when the load current exceeds the limit of an MCB. Besides offering greater protection against overload and short circuit faults—it is also used for switching the circuits.

MCCB is employed for higher current rating and expected fault levels. Due to it wider current ratings and higher breaking capacity, MCCB is commonly used in industrial setups. Whenever the installation requires adequate protection along with adjustable overload setting or earth fault protection—MCCB is the device of choice.

Difference between MCB and MCCB

RCCB

Taking circuit breaking capacity a notch up — RCCB or Residual Current Circuit Breaker is a standard protective device, recognized as essential lifesaving equipment. It disconnects the circuit offering protection against electrical leakage or electric shock caused by direct contacts. RCCB is generally used in series with an MCB to ensure protection from over current and short circuit current.

ELCB

ELCB or an Earth Leakage Circuit Breaker has fundamentally the same function as RCCB, except for the voltage sensor capabilities. In simpler terms, ELCB interrupts the circuit if a dangerous voltage level is detected. As a safety device, it protects electrical installations with high earth impedance by detecting small stray voltages.

Difference between RCCB and ELCB

End note

Though it is helpful to know the differences between circuit breakers—the recommendation for their installation must come from an expert. Circuit breakers are not mere essential electrical devices, they are life saviors in large electrical installations.