What Is the Difference Between ELCB and RCCB? . A circuit breaker is an electrical switch that is designed to operated manually as well as automatically either in normal conditions or in case of a fault in the system. Therefore, a circuit breaker can also function as a protective device which can protect the system equipment and the operators.
There are several circuit breakers are designed for this purpose, two of them are ELCB and RCCB. In this article, you will learn what ELCB and RCCB are, and what are the major differences between them.
Read More : What is an Oil Circuit Breaker?
What is an ELCB (Earth Leakage Circuit Breaker) ?
ELCB stands for Earth Leakage Circuit Breaker. The ELCB is a safety device that protects a person from the electric shock when it comes in contact with a faulty device.
An ELCB consists of a coil that is connected in series with the earth terminal. When phase wire comes in contact with the body of the equipment, a voltage is developed in the earth conductor. This voltage operates the ELCB to trip the circuit.
There are following three types of ELCBs (Earth Leakage Circuit Breakers)
- AC – for alternating current
- A – for square wave current
- B – for direct current
The earth leakage circuit breaker (ELCB) is not commonly used nowadays, and is replaced by a new circuit breaker known as RCCB.
Read More : Can We Use AC Circuit Breaker for DC Circuit and Vice Versa?
Operation:
- ELCBs operate by sensing the current difference between the live (phase) and neutral conductors.
- When a leakage current flows to the earth (ground), causing an imbalance, the ELCB detects this and trips to disconnect the circuit.
- By cutting off the power supply swiftly upon detecting such leakage, ELCBs help prevent severe electrical accidents.
Applications:
- ELCBs were widely used in older electrical installations to protect against earth faults.
- They are suitable for circuits where the risk of earth leakage is significant but do not provide protection against other types of faults.
Advantages of ELCB
- Enhanced Safety: Prevents electrocution and mitigates fire risks caused by earth leakage.
- Simple Mechanism: Easy to install and maintain.
- Cost-Effective for Older Systems: Ideal for retrofitting in legacy electrical setups.
Limitations of ELCB
- Outdated Technology: Less reliable in modern setups with complex electrical loads.
- Voltage Dependency: Ineffective if the earth connection is lost or compromised.
- Compatibility Issues: May not function well with newer wiring standards.
Read More : Difference between Circuit Breaker and Isolator / Disconnector
What is an RCCB (Residual Current Circuit Breaker)?
RCCB stands for Residual Current Circuit Breaker. The residual current circuit breaker (RCCB) works on the principle of core balancing current transformer, i.e. it compares the currents flowing through the phase and neutral wires.
RCCB monitors the vector sum of currents through the phase wire and neutral wire, if the current flowing through the phase wire to the load returns back to the supply through the neutral wire, then their vector sum is zero. Hence, the RCCB does not operate.
Now, if there is any fault or a living being touches the phase wire, which results in the flow of some leakage current from phase wire to the earth. In this case, current in the phase wire and neutral wire becomes unequal and thus their vector sum is not equal to zero. Under this condition, the core balancing current transformer of RCCB sends an unbalance current to the relay’s operating coil. Therefore, the RCCB trips the circuit and isolate the faulty circuit from the healthy circuit.
Read More : Difference Between Relay and Circuit Breaker
Operation:
- RCCBs work by continuously monitoring the balance between the live and neutral currents.
- If an imbalance is detected, indicating leakage to earth or through a person, the RCCB rapidly disconnects the circuit.
- This capability makes RCCBs more sensitive and effective in detecting a more comprehensive range of faults than ELCBs.
Applications:
- RCCBs are commonly used in modern electrical installations where higher levels of safety are required.
- They are essential for protecting against direct and indirect contact with live parts, thereby minimizing the risk of electric shocks.
Advantages of RCCB
- Advanced Safety: Offers superior protection against electrical shocks and fire hazards.
- Wide Sensitivity Range: Detects leakage currents as low as 30mA, ensuring early fault detection.
- Compliance with Modern Standards: Suitable for homes, offices, and industrial setups.
Limitations of RCCB
- Higher Sensitivity: May trip unnecessarily if exposed to transient currents.
- Cost: More expensive than traditional ELCBs.
- No Overcurrent Protection: Requires an additional MCB (Miniature Circuit Breaker) for full protection.
Read More : How to Find the Number of Outlets on a Single Circuit Breaker?
Difference Between ELCB and RCCB
ELCB (Earth Leakage Circuit Breaker):
ELCB is primarily designed to detect small leakage currents typically caused by faulty insulation. It detects the imbalance between the phase conductor and the neutral conductor. When such an imbalance is detected, indicating leakage to earth, the ELCB trips to disconnect the circuit, thereby preventing electric shocks and fire hazards.
RCCB (Residual Current Circuit Breaker):
RCCB, also known as RCD (Residual Current Device), is an enhanced version of the ELCB. Unlike the ELCB, which detects only earth leakage, the RCCB can detect leakage to earth and any other unintended path, such as through a person. This is achieved by comparing the current flowing in the live conductor with that returning in the neutral conductor. If an imbalance is detected, indicating leakage, the RCCB trips to cut off the power supply swiftly, thus offering superior protection against electric shocks.
Read More : Why Use VCB Circuit Breakers in HV Transmission and Not ACB?
Difference between ELCB and RCCB
Both RCCB and ELCB are the protecting devices. However, there are several differences between ELCB and RCCB that the following table highlights
| Basis of Difference | ELCB | RCCB |
|---|---|---|
| Full Form | ELCB stands for Earth Leakage Circuit Breaker. | RCCB stands for Residual Current Circuit Breaker. |
| Definition | A safety device that is used in the electrical installation with high earth impedance to prevent the electric shock is called earth leakage circuit breaker (ELCB). | A safety device used in electrical installation that trips the circuit against the electrical leakage currents to ensure the protection from electric shocks due to indirect contacts is called residual current circuit breaker (RCCB). |
| Type of device | ELCB is a voltage operated device. | RCCB is a current operated device. |
| Connection | ELCB is connected to phase, neutral and earth wires. | RCCB is connected to phase and neutral wires only. |
| Fault detection | ELCB detects only those electrical faults in which the earth leakage current flows through the main earth wire. | RCCB can detect any kind earth faults. |
| Working principle | The working principle of an ELCB is based on the earth leakage current flowing through the main earth wire. | The working of an RCCB is based on the principle of core balancing current transformer (CBCT). |
| Monitoring of earthing status | ELCB monitors the earthing status of the system. It ensures that the system is perfectly connected to the earth. | RCCB does not monitor the earthing status of the electrical system. |
| Need of earth connection | ELCB requires an earth connection to function. | In case of RCCB, there is no need of an earth connection to function. |
| Nuisance tripping | The nuisance tripping is the beak in the power supply without the situation being really hazardous. In ELCB, the nuisance tripping is less. | The nuisance tripping in an RCCB is high. |
| Cost | The cost of ELCB is more. | RCCB is comparatively less expensive. |
| Applications | ELCB is an old safety device used in electrical installations to,protect from electric shocks. | RCCB is a new technology used in almost all wiring systems to provide protection against earth leakage currents. |
Read More : How to Wire a GFCI Circuit Breaker?
How to Choose Between ELCB and RCCB?
When deciding between an ELCB and an RCCB, consider the following:
- Age of the Electrical System: Use ELCBs for older systems; RCCBs for modern setups.
- Safety Requirements: Opt for RCCBs where advanced protection is necessary.
- Budget Constraints: ELCBs are cost-effective but may lack critical safety features.
- Regulatory Standards: Comply with local electrical safety codes.
Read More : Types of Circuit Breakers : Working and Applications
Frequently Asked Questions (FAQs)
1. Can an RCCB replace an ELCB?
Yes, RCCBs can replace ELCBs, offering improved safety and compliance with modern standards. However, compatibility with the existing wiring must be assessed.
2. Do I need both an RCCB and an MCB?
Yes, RCCBs protect against current leakage, while MCBs protect against overcurrent. Together, they provide comprehensive safety.
3. Why does my RCCB trip frequently?
Frequent tripping can be caused by ground faults, defective appliances, or transient currents. Proper diagnosis by a professional is recommended.
4. Are ELCBs still in use?
ELCBs are gradually being phased out but are still used in older systems where modern alternatives are not feasible.
