First we want to know what is ELCB and RCCB then only we can easily find out the difference between ELCB and RCCB.
ELCB is termed as earth leakage circuit breaker. and further more about ELCB we can see below,
- 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
RCCB is termed as residual current circuit breaker.and further more about RCCB we can see below,
- Phase (line) and Neutral both wires connected through RCD.
- It trips the circuit when there is earth fault current.
- The amount of current flows through the phase (line) should return through neutral .
- It detects by RCD. any mismatch between two currents flowing through phase and neutral detect by RCD and trip the circuit within 30Miliseconed.
- If a house has an earth system connected to an earth rod and not the main incoming cable, then it must have all circuits protected by an RCD (because u mite not be able to get enough fault current to trip a MCB)
- The most widely used are 30 mA (milliamp) and 100 mA devices. A current flow of 30 mA (or 0.03 amps) is sufficiently small that it makes it very difficult to receive a dangerous shock. Even 100 mA is a relatively small figure when compared to the current that may flow in an earth fault without such protection (hundred of amps)
- A 300/500 mA RCCB may be used where only fire protection is required. eg., on lighting circuits, where the risk of electric shock is small
- RCDs are an extremely effective form of shock protection.
Difference between ELCB and RCCB
- ELCB is the old name and often refers to voltage operated devices that are no longer available and it is advised you replace them if you find one.
- RCCB or RCD is the new name that specifies current operated (hence the new name to distinguish from voltage operated).
- The new RCCB is best because it will detect any earth fault. The voltage type only detects earth faults that flow back through the main earth wire so this is why they stopped being used.
- The easy way to tell an old voltage operated trip is to look for the main earth wire connected through it.
- RCCB will only have the line and neutral connections.
- ELCB is working based on Earth leakage current. But RCCB is not having sensing or connectivity of Earth, because fundamentally Phase current is equal to the neutral current in single phase. That’s why RCCB can trip when the both currents are deferent and it withstand up to both the currents are same. Both the neutral and phase currents are different that means current is flowing through the Earth.
- Finally both are working for same, but the thing is connectivity is difference.
- RCD does not necessarily require an earth connection itself (it monitors only the live and neutral).In addition it detects current flows to earth even in equipment without an earth of its own.
- This means that an RCD will continue to give shock protection in equipment that has a faulty earth. It is these properties that have made the RCD more popular than its rivals. For example, earth-leakage circuit breakers (ELCBs) were widely used about ten years ago. These devices measured the voltage on the earth conductor; if this voltage was not zero this indicated a current leakage to earth. The problem is that ELCBs need a sound earth connection, as does the equipment it protects. As a result, the use of ELCBs is no longer recommended