Disadvantages
ELCBs have some 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 bonded to pipework.
- 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 with RCDs, 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.
Read more about this topic: Earth Leakage Circuit Breaker