The Difference Between Earth Leakage Circuit Breaker, MCCB, and RCCB

The difference between Earth Leakage Circuit Breakers (ELCBs), Molded Case Circuit Breakers (MCCBs), and Residual Current Circuit Breakers (RCCBs) is their working principle and cost.

In this blog, you will not only learn about their functions and cost, but the following aspects, too:

• Maintenance.
• Current rating.

Let’s begin!

ELCBs, MCCBs, and RCCBs: What’s the Difference?

Most circuit breakers revolve around the same function: to prevent current leakage.

However, ELCBs, MCCBs, and RCCBs slightly differ in the following:

• Working principles.
• Current rating.
• Cost.
• Maintenance requirements.

Working Principle

To begin, ELCBs work by monitoring the current flow through their winding transformers.

When earth faults occur, the sensing coils in the circuit identify the imbalance in current flow.

The ELCB then calculates the difference in current flow from the threshold, which shuts off the power supply automatically.

MCCBs, on the other hand, are typically beneficial to control AC and DC switching.

This device helps protect short circuits by acting as a border between the load and the power source.

What makes MCCBs different is that they contain an arc between the terminals that causes a magnetic field around the gap.

This magnetic field either repels or attracts metal objects that touch the said gap.

The MCCB continues to generate an electric current through the gap even if the circuit breaker has shut the power off.

Meanwhile, an RCCB’s working principle begins with the standard requirement: the current flow in the live wires should be equal to the returning current in the neutral wires.

When an earth fault occurs, the current escapes to the earth (i.e. touching a live wire).

What happens next: the returning current in the neutral wire is now reduced. Hence, called residual current.

This is where the RCCB’s work begins.

The breaker now continuously detects and analyzes the residual current between the live and neutral wires.

RCCBs will shut off the circuit when they identify a small residual current or difference in values.

Current Rating

ELCBs current rating can be up to 650 amperes. 

On the other hand, an MCCB’s current rating can be up to 1000 amperes, which makes it suitable for low and high-voltage applications.

Meanwhile, an RCCB’s current rating can be up to 125 amperes, which is suitable for low-power applications.

Cost

The cost for circuit breakers can vary depending on the classification, current rating, and brand.

ELCBs usually cost up to $200.

On the other hand, MCCBs are usually priced up to a thousand dollars due to their high-voltage current rating and overall functionality.

Meanwhile, RCCBs typically cost around $30 to $100.

Maintenance

ELCBs, MCCBs, and RCCBs need regular maintenance in order to function properly.

Here are the signs that your circuit breakers need maintenance checks:

• Old breakers.
• Overheating circuit breaker.
• Discoloration or burn marks.
• No tripping at all even if there are earth faults.
• Frequent and unusual tripping without ground faults.
• Electrical shocks when using certain appliances or equipment.

Key Takeaway

Circuit breakers (ELCB, MCCB, and RCCB) play a vital role in ensuring the safety of humans and animals from electrocution caused by ground faults.

These circuit breakers function according to their respective current rating.

Hence, they may differ in cost and installation fees.