RCCB vs ELCB vs Isolator

RCCB vs ELCB vs Isolator
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When we point out “electrical safety”, we think about protection from electrical hazards. Definitely RCCB and ELCB are primary devices which we get in our mind. These comes under circuit breaker category and very useful during electrical design of wiring of premises. Circuit breaker are devices which trips electrical circuit in case of fault occurs. Nomenclature and working of circuit breaker depends on types of fault. We should not mix in circuit breaker and isolator. Both are used for circuit protection in electrical wiring and transmission. We will discuss about RCCB vs ELCB vs Isolator here.

Types of Electrical faults

We use term “fault” in our daily life which means some error happen. Same way, term “Electrical Fault” is used when any error happens during normal operation of electrical system. Electrical fault are majorly categorized :-

  1. L-G fault, Line to ground fault, (Asymmetric fault)
  2. L-L fault, Line to line fault, (Asymmetric fault)
  3. LL-G fault, Double line to ground fault, (Asymmetric fault)
  4. LLL-G fault, triple line to ground fault, (Symmetric fault)
  5. LLL fault, triple line fault, (Symmetric fault)

As per above five types of electric fault, L-G is less severe but most common fault. While LLL and LLL-G fault is very severe but rare fault in electric system.

Circuit Breakers

Circuit breakers are protective parts of any electric system which disconnect electrical circuit in case of fault during onload condition. MCB, MCCB, VCB, RCCB, ELCB etc are very common types of circuit breaker.In which RCCB and ELCB are most commonly used in electric wiring for earth leakage and human hazards prevention.


ELCB is safety device which is used for tripping circuit when there is any earth leakage. Earthing is essential for ELCB (earth leakage circuit breaker).

Electric breaker and isolator, RCCB vs ELCB vs Isolator

Let us understand with an example, A person (Ram) is working on electric equipment. Accidentally he touches its body, then some part of current flows throw Ram’s body.As per norms, equipment body is connected with earth through earth wire. This fault current will pass through ELCB and circuit breaker trips.

ELCB had one addition terminals for earthing connection. In other word, we can say that ELCB trips circuit only when we had a healthy earthing along with proper connectivity.


In above example, if earthing connection is broken, ELCB will not work. Here we have to install RCCB, which is independent of earthing due to its basic nature and working principle. RCCB will work on difference of current in Live and Neutral wire. So we can use it most effectly in domestic and commercial wiring where human interference is in high magnitude.


In the above video we can get clear details RCCB vs ELCB vs Isolator

For general use we should of 30mA rating for best practices. We can use 100mA and 300mA where we need less nuisance false tripping and human interference is less with electrical parts.


Isolators are another layer of protective parts in electric system which disconnect electrical circuit during Offload condition. It is commonly used when we need repairing and maintenance of transmission lines.

FOR more details please refer video

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17 thoughts on “RCCB vs ELCB vs Isolator

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