MCBs and MCCBs have commonly used circuit protection devices. These devices provide protection against overcurrent and short circuits. In this article, let us discuss the difference between MCB and MCCB.
Overview of MCB:
- These are thermal / thermo-magnetic devices
- Provides protection against overcurrents and short circuits.
- Available up to 100A and have a maximum short circuit capacity of 25kA.
- Commonly used in lighting circuits.
- The trip level cannot be varied.
- Available in single, two, three, and four-pole versions.
Overview of MCCB:
- Maybe Thermal/ Thermo-Magnetic/ Electronic trip type
- Primarily provide protection against over-current and short circuits.
- Can provide protection against Earth Fault, Residual Currents, Under voltage, etc
- Available up to the rating of 2500A.
- The trip level can be varied in adjustable trip type MCCBs.
- Remote ON/OFF is possible with additional accessories
- Commonly used are loads over 100A and motor protection circuits.
- Some MCCBs are microcontroller based.
- Available in single, two, three, and four-pole versions.
The major difference between MCB and MCCB
- The principle of operation of MCBs is based on the thermal property of current whereas MCCB is a microprocessor-based device that uses current sensors to measure the magnitude of current and isolate a circuit.
- The maximum normal current rating of an MCB is 125A whereas that of an MCCB is 1600A.
- The maximum short circuit capacity of an MCB is 15kA whereas the maximum short circuit rating of an MCCB is 85kA
- The trip characteristics of an MCB are fixed and preset. But characteristics of an MCCB can be varied based on application.
- MCBs are designed to protect residential loads and small electronic loads whereas MCCBs are capable of handling much heavier industrial loads.
Comparison of MCB and MCCB
| MCB | MCCB | |
|---|---|---|
| Maximum rated current | MCBs are available up to the rating of 125A. | MCCBs are available up to the rating of 1600A. |
| Maximum breaking capacity | The short circuit current that the MCB can safely interrupt ranges between 5kA and 25kA, depending on its design. | The short circuit current that the MCCB can safely interrupt ranges between 25kA and 100kA, depending on its design. |
| Tripping current | The trip current of the MCB is fixed and cannot be adjusted. | The trip current of the MCCB is fixed and cannot be adjusted, provided that it is a microcontroller-based device. |
| Remote operation | Remote operation tripping is not possible. | MCCBs can be opened and closed from a remote using suitable accessories. |
| Application | An MCB is best suited for the protection of smaller loads, lights, home appliances, and electronic devices. | MCCBs are suitable for the protection of heavy industrial loads and machinery. |