VADODARA INSTITUTE OF ENGINEERING

Prepared By: Deepak Chawda

(160800119007) Akash Chaurasia

(160800119008) Stanley Christy

(160800119009) Shivam Dave

(160800119010)

Guided By: Prof. Rajan Modha

Earth Leakage Circuit Breaker (ELCB)

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An Earth Leakage Circuit Breaker (ELCB) is a device used to directly detect currents leaking to earth    from an installation and cut the power .There are two types of ELCBs:

1. Voltage Earth Leakage Circuit Breaker (voltage-ELCB) 2. Current Earth Leakage Current Earth Leakage Circuit Breaker (Current-ELCB).

The ELCB detects fault currents from live to the earth (ground) wire within the installation it protects. If sufficient voltage appears across the ELCB’s sense coil, it will switch off the power, and remain off until manually reset. A voltage-sensing ELCB does not sense fault currents from live to any other earthed body.

The way to identify an ELCB is by looking for green or green and yellow earth wires entering the device. They rely on voltage returning to the trip via the earth wire during a fault and afford only limited protection to the installation and no personal protection at all. You should use plug in 30mA RCD’s for any appliances and extension leads that may be used outside as a minimum.

 Advantages

ELCBs have one advantage over RCDs: they are less sensitive to fault conditions, and therefore have fewer nuisance trips..While voltage and current on the earth line is usually fault current from a live wire, this is not always the case, thus there are situations in which an ELCB can nuisance trip.

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When an installation has two connections to 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..If the installation’s earth rod is placed close to the earth rod of a neighboring building, a high earth leakage current in the other building can raise the local ground potential and cause a voltage difference across the two earths, again tripping the ELCB..

Disadvantages

They do not detect faults that don’t pass current through the CPC to the earth rod.

They do not allow a single building system to be easily split into multiple sections with independent fault protection, because earthing systems are usually use common earth Rod.

They may be tripped by external voltages from something connected to the earthing system such as metal pipes, a TN-S earth or a TN-C-S combined neutral and earth.

As electrically leaky appliances such as some water heaters, washing machines and cookers may cause the ELCB to trip.

ELCBs introduce additional resistance and an additional point of failure into the earthing system.

Thank you