Difference between MPCB and MCCB

Motor protection circuit breakers ad moulded case circuit breakers both are low voltage AC circuit protection devices. It is used to open and close the circuit manually and interrupt the circuit automatically on the occurrence of faults. MPCB and MCCB both are used to protect against overload and short circuits. Here any query regarding this topic please give a comment below as well as any opinion regarding this topic please inform me in the comments section.

Difference between MPCB and MCCB :

  • MPCB stands for motor protection circuit breaker while in MCCB stands for molded case circuit breaker. 
  • MPCB is used to manually turn on and off electric motors and at the same time protect them from different types of faults occurring in motors while in MCCB are used in power distribution and low voltage distribution circuits as well as motors loads.
  • MPCB is specially designed for motor protection while in MCCB are specially designed for general-purpose circuit protection.
  • MPCB can protect the motor against overload, short circuit, phase loss, and under-voltage faults while in MCCB can protect the motor against overload and short circuits. This circuit can also provide under-voltage, earth faults, and phase failure faults but these features are made available with additional accessories.
  • MPCB can withstand the stating currents without interrupting the circuit while in MCCB is used as backup protection for a motor, it may interrupt the circuit if it is selected based on its full load current.
  • MPCB is maximum load current can be set based on the full load current of the motor while in MCCB is overload, short circuit and trip relay delay time can be set based on the applications.
  • MPCB is selected based on the full load current of motors and maximum possible short circuit current while in MCCB are selected based on the maximum current and maximum short circuit current interrupt safety. 
  • MPCB has an adjustable bimetallic strip for overload protection. this strip can be adjusted between two set values but the MCCB overload value of MCCB can be  40% to 100% of its rated value.
  • MPCB can protect a motor against overload and short circuit while in MCCB when used in motor protection circuit can protect against short circuit only. Hence additional overload relay and contactor.
  • A motor can be directly ON and OFF manually using an MPCB, the contactor is optional while in  MCCB contactor is a must in these cases.
  • Some MPCB comes with auto-resetting features that allow motors to resume its operation after a short period from the occurrence of overload trip while in MCCB is feature is not available.
  • Overload relay is not required for motor circuits with MPCB backup but in MCCB overload relay is required.
  • Some MPCB comes with an auto-resetting feature that allows motors to resume its operation after a short period from the occurrence of an overload trip while in MCCB feature is not available.

Difference between ammeter and ohmmeter

An ammeter is an instrument used to measure the current through a circuit is connected in series with the component through which the current is to be measured whereas voltmeter is an instrument used to measure the voltage across the two ends. The comparison, definition, and the difference between them are explained below. 

Definition of ammeter:

The meter has used for measuring the current is known as the ammeter. As we learn, the current in the flow of electrons whose unit is ampere to measure current flows in ampere meter or ammeter.

Definition of ohmmeter:

An ohmmeter measures the basically resistance and also a continuity of electrical circuit and their components. 


Difference between ammeter and ohmmeter:

  • The ammeter measures current while ohmmeter measures resistance.
  • The ammeter is connected in series but in ohmmeter is connected in parallel.
  • In ammeter, the current is measured in amperes while in ohmmeter is an electrical instrument that measures electrical resistance. 
  • In an ammeter instrument used to measure smalled currents in the milliampere or some microampere range are designated as millimetres or micrometres while in micro ohmmeter is used low resistance measurement while Megaohammters measure the large values of resistance. 
  • While using an ammeter positive ad negative terminal need to be aligned with a circuit, while checking current, we do not need to take care of positive ad negative terminals while calculating resistance in an ohmmeter. 
  • The ohmmeter is very convenient the use but less accurate compare to an ammeter.
  • An ammeter is four of type permanent moving coil ammeter, moving iron ammeter, electrodynamometer ammeter, rectifier type ammeter while in ohmmeter is of three types series ohmmeter, shit ohmmeter ad multi range ohmmeter, this is the type of construction while in current category there are two types AC ammeter and DC ammeter.

Difference between MCB and RCBO

MCB stands for miniature circuit breaker while RCBO stands for a residual current circuit breaker with overload protection, this both are circuit protection devices. These devices are most commonly used in the distribution board in the office, home, theatre, commercial building, low voltage power distributions, etc.

What is MCB?


MCB is designed to operate on overload current and they can be used as protection devices for the individual circuit. MCB can also provide magnetic fault protection and short circuit protection.

What is RCBO?


As the name suggests the operating fundamental of RCBO is to operate on residual as well as overload current. RCBO is a combination of MCB and RCCB. When in some current imbalance occur the RCCB will operate ad when there is overload in the circuit breaker will operate.

Difference between MCB and RCBO :

  • MCB stands for miniature circuit breaker while RCBO stands for a residual current circuit breaker with overload protection.
  • MCB can provide protection against overcurrent and short circuit only while RCBO can provide protection against overcurrent and earth leakage.
  • MCb can not protect against earth faults while in RCBO can protect against earth fault, electric shocks that MCB may not do.
  • MCB is selected based on the load, the maximum short circuit during overload and short circuit,  RCBO is the combination of MCB and RCCB. It is selected based on the load and maximum short circuit current it ca interrupt, trip curve and maximum leakage current.
  • MCB is used to protect lighting circuits, air conditioners and other home applications RCBO is used for protection against electric shocks. Hence it is mainly used to interrupt the power to water heaters, power sockets, etc. 
  • MCB is monitoring the current flow through the line and interrupts the circuit during overload and short circuit, while RCBO is not only monitoring but the current flow through the line interrupt the circuit during overcurrent, short circuit, and earth leakage.

RCCB advantages

RCB called as the Residual current circuit breaker, it is nothing but quickly breaks an electrical circuit to prevent serious harm from an ongoing electric shock. Let us have a deep insight into the advantages and disadvantages given by RCCB. 

Advantages of RCCB:

  • The main purpose of RCCB is to protect the human from the residual current.
  • It is used to protect against the earth's fault as well as electrical shock.
  • It automatically disconnects the circuit when the rated sensitivity is exceeded.
  • It offers protection against voltage fluctuations as it includes a filtering device that guards against transient voltage levels.
  • It offers the possibility of dual termination both for cable and busbar connection.

Disadvantages of RCCCB:

  • RCCB does not have short circuit protection.
  • Nuisance tripping of RCCB.
  • RCD doesn't offer protection against current overloads.
  • This circuit breaker will not protect against a socket outlet being wired with its live and neutral terminals the wrong way round.
  • RCCB is a higher cost.
  • This circuit breaker will not protect against live neutral shocks, because of the current in life and neutral in balanced.
  • RCCB does not protect from the overheating that strike if conductors are not properly screwed into terminals.
  • RCCB does not guarantee to operate if none standard waveform is generated by a load. It is mainly because RCCB is designed to operate on normal supply waveform.

Advantages and disadvantages of ELCB

ELCB stands for  Earth leakage circuit breaker, It is one kind of safety device used for installing an electrical device with the high earth impedance to avoid shock. The main advantage of the Earth leakage circuit breaker is to stop damage to humans and animals due to the electric shock. Let us have to deep inside the information about the merits and demerits of Earth leakage circuit breaker to better understand this topic.

Advantages of ELCB:

  • This device is not sensitive to faults.
  • It is cheap and efficient.
  • It protects animals and humans from electrical shock.
  • In this process, when the installation has two connections to the earth, a nearby high current lightning strike will cause a voltage gradient in the soil, presenting the ELCB sense coil with enough voltage to cause it to trip.

Disadvantages of ELCB:

  • Failure to respond at certain conditions.
  • ELCB needs a sound earth connection, for the load protects.
  • Nuisance trips.
  • Electrical leaky appliances water heater, washing, machine, and coolers may cause CKL to trip.
  • They may be tripped by the external voltage from something connected to the earthing system such as a metal pipe.
  • They do not detect a fault that doesn't pass current through CPC to earth rod.
  • They do not allow a single building system to easily split into multiple sections with independent fault protection because the earthing system is bonded to the pipework.
  • If the electrical installation earth rod is placed close to another earth of a building, then a high earth leakage current from other buildings can raise the local ground potential and cause a voltage difference across the two earth, again tripping the ELCB.
  • ELCBs introduce additional resistance and an additional point of failure into enough voltage to cause it to trip.
  • They may be tripped by external voltage from something connected to the earthing system such as metal pipes, TN-S earth or a TN-C-S combined neutral and earth. 

Difference between RCCB and ELCB

ELCB measure the voltage in earth link wire or ground wire to trip whereas RCCB measure sum of currents in neutral and phase to trip. They both are different in function but not in design and speed. Let us have a deep insight into the definition of ELCB and RCCB and the difference between them in this article. 


What is ELCB?

The ELCB stands for, Earth Leakage Circuit Breaker, it is a  basically safety device is used in electrical installations with high earth impedance to prevent shock. It detects small stray voltages on the metal enclosures of electrical equipment and also interrupts the circuit if some dangerous voltage is detected.

What is RCCB?

RCCB stands for Residual Circuit Breaker, It is essentially a current sensing device used to protect a low voltage circuit in case of a fault. It contains some switch device that switches off whenever some fault occurs in the connected circuit. 

Difference between ELCB and RRCB :

  • RCCB is the new name that specifies a current operated new name to distinguish from voltage-operated while ELCB is the old name and often refers to voltage operated devices that they are no longer available and it also advised you replace them if you find one.
  • RCCB stands for residual case circuit breaker while ELCB stands for earth leakage circuit breaker.
  • ELCB is an old technology while RCCB is a new technology.
  • ELCB is connected to phase, natural as well as earth line, RCCB is connected only phase and natural line. 
  • Both are working for the same, but the thing is connectivity is the difference.
  • RCCB does not monitor the system earthing status. It monitors only the live and neutral while in ELCB ensure the system is connected on perfect earth which means ELCB sense the connectivity of earthing.
  • In ELCB cost is high compare to RCCB.
  • ELCB is not recommended over RCCB while in RCCB  is also known as the current operated ELCB.
  • ELCB detect earth faults that flow back through the main earth wire, RCCB will detect any earth faults, that's why they are using mow instead of ELCB.
  • ELCB is working based on earth leakage current while RCCB is not having sensing or connectivity of earth because fundamentally phase current is equal to the neutral current in a single phase.

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Difference Between isolator and circuit breaker

As we know that both isolators and circuit breakers switch to isolate a section of the power system but one point is that the isolator is an offload device while in the circuit breaker in on load device. Let us have a deep insight into what is an isolator and circuit breaker and key difference between them in this article. 

Definition of isolator:

An isolator is just like a switch, only can be operated under offload condition. It mostly used in industry-level applications. It can not protect the circuit under fault conditions. 

Definition of circuit breaker:

A circuit breaker is basically a protecting switch, it can be operated both manually as well as auto, actually. It follows the instruction of protecting devices under various fault conditions such as over current, short circuit, etc.

Difference between isolator and circuit breaker : 

  • The isolator is switch operated manually while the circuit breaker is operated automatically.
  • The isolator is an electronics device made by using MOSFET or BJT while the circuit breaker is a mechanical device that acts as a switch.
  • Isolator has a low withstand capacity as compared to that of the circuit breaker.
  • The isolator is an offload device while the circuit breaker is an on load device.
  • The isolator is meant only for interrupting the power during maintenance or repair while in circuit breaker are meant for protection of a circuit or equipment from short circuit and overload faults while they are in operations.
  • The breaking capacity of isolators is very less compared to the circuit breaker.
  • In isolator protection relay does not require while in circuit breaker protection relay control the breaker.
  • Isolator has a less cost while in circuit breaker has a high cost.
  • In isolator atmospheric air is used as arc quenching medium while in circuit breaker different kinds of a medium are used in typically atmospheric.
  • Isolator has high safety while in circuit breakers need well-trained technicians.
  • Arc quenching medium is used for isolator while in circuit breaker SF6  and vacuum atmospheric air were used.
  • Physical contact status can be seen. since they are necessary during the maintenance process while in the circuit breaker we cannot see the physical condition.
  • Isolator cuts out a portion of a substation when some fault occurred. Some other devices operate without any interruption, but in the circuit breaker know as an automatic circuit breaker which trips the entire system if any fault occurs and thus the whole system is affected.