What is the main difference between MCB & ELCB?

A Miniature Circuit Breaker. An MCB is a device designed to protect a circuit's wiring from the serious damage which would be caused if it has to carry a current which is too high for the diameter of its wires.

MCB:

• Trip characteristics normally not adjustable.
• Thermal or thermal-magnetic operation.

 

The name  Earth Leakage Circuit Breaker(ELCB) was   given to a device that breaks the power supply when a fixed amount of  current ,say 25-40 milli amperes flow through the earth line.

 

ELCB:

• Phase (line), Neutral and Earth wire connected through ELCB.
• ELCB is working based on Earth leakage current.
• Operating Time of ELCB:
• The safest limit of Current which Human Body can withstand is 30ma sec.
• Suppose Human Body Resistance is 500Ω and Voltage to ground is 230 Volt.
• The Body current will be 500/230=460mA.
• Hence ELCB must be operated in  30maSec/460mA = 0.65msec

 

MCB-will trip the load as per designed Rating and curve. ELCB-EARTH LEAKAGE CIRCUIT BREAKER,ELCB sensitive for earth leakage

MCB (Miniature Circuit Breaker)

ELCB (Earth Leakage Circuit Breaker)  was   given to a device that breaks the power supply when a fixed amount of  current, say 25-40 ml amperes flow through the earth line. The ELCB is  now called as Ground Fault Circuit Interrupter (GFCI).

A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current, typically resulting from an overload or shortcircuit. Its basic function is to interrupt current flow after a fault is detected.

An Earth-leakage circuit breaker (ELCB) is a safety device used in electrical installations with high Earth impedance to prevent shock. It detects small stray voltages on the metal enclosures of electrical equipment, and interrupts the circuit if a dangerous voltage is detected

ELCB :

An Earth Leakage Circuit Breaker was the first name given to what is now called a Ground Fault CircuitInterrupter (GFCI) . The original type of ELCB or GFCI was designed only to detect a current flowing in the safety "ground" or "earth" wire. If there is no fault anywhere in a circuit supplying single-phase alternating power to a unit such as an electrical appliance, machine or other equipment, the current flowing to the unit at any instant in the "hot" or "live" wire should exactly match the current flowing away from the unit in the neutral wire. Similarly, there should be no current flowing in the unit's safety "ground" or "earth" wire. It is a basic fact of electrical engineering design that all current flowing to an electrical appliance, machine or other equipment from the power generation station via its supply circuit's "hot" or "live" wire should only return to the power station via that same circuit's "neutral" wire. So, as a result of that basic fact, if any current is flowing in the ground wire, it must be caused by a fault condition and the supply of current to the circuit needs to be stopped urgently. Many years ago, before today's electronic RCDs or GFCIs were designed, much simpler electro-mechanical relays called EarthLeakage Circuit Breakers (ELCBs) were invented so that, if any such ground current exceeding just a few milliamps was detected, they would "trip" - meaning "operate" - to break the current supply to the circuits for which they were installed to protect.

The original type of ELCB or GFCI did not check for any difference in current flowing in the live and neutral wires, which is another indication of a very serious fault condition - even if no current can be detected flowing in the ground wire - because the "missing current" may actually be flowing to ground via someone's body! When RCDs were invented, most manufacturers of GFCIs adopted the same technology because it offers so much more protection to users than the original GFCI could ever give. In the US and Canada such devices are still commonly known as "GFCIs" or "GFIs" even though they have the additional "residual current detector" functionality, whilst in Europe and elsewhere the more accurate name of "Residual Current Detector" or RCD has been widely adopted for general use instead of using the name of the much simpler GFCI device.

MCB :

Nowadays we use more commonly miniature circuit breaker or MCB in low voltageelectrical network instead of fuse. The MCB has some advantages compared to fuse.

1. It automatically switches off the electrical circuit during abnormal condition of the network means in over load condition as well as faulty condition. The fuse does not sense but miniature circuit breaker does it in more reliable way. MCB is much more sensitive to over current than fuse.
2. Another advantage is, as the switch operating knob comes at its off position during tripping, the faulty zone of the electrical circuit can easily be identified. But in case of fuse, fuse wire should be checked by opening fuse grip or cutout from fuse base, for confirming the blow of fuse wire.
3. Quick restoration of supply can not be possible in case of fuse as because fuses have to be rewirable or replaced for restoring the supply. But in the case of MCB, quick restoration is possible by just switching on operation.
4. Handling MCB is more electrically safe than fuse. Because of to many advantages of MCB over fuse units, in modern low voltage electrical network, miniature circuit breaker is mostly used instead of backdated fuse unit.

Only one disadvantage of MCB over fuse is that this system is more costlier than fuse unit system.

MCB miniature circuit breakers main function to protect against short circuit faults and overload (magnetic and thermal protection) while ELCB earth leakage circuit breaker main function to break the power supplywhen there is any current leakage.

Earth Leakage Circuit Breaker(ELCB) was   given to a device that breaks the power supply when a fixed amount of  current ,say 25-40 milli amperes flow through the earth line. The MCB (Miniature Circuit Breaker) is a device designed to protect a circuit’s  wiring from the serious damage which would be caused if it has to carry  a current which is too high for the diameter of its wires.

MCB-Miniature circuit breaker, it will trip the load as per designed Rating and curve.

ELCB-EARTH LEAKAGE CIRCUIT BREAKER,ELCB sensitive for earth leakege,Normally for domestic 30ma and Industriel 100Ma.