Earthing Questions

<...why two body earthing & two neutral earthing will be done for transformers?...>

1. So that the circuit protective devices can operate to disconnect any fault, thereby protecting the equipment, the cabling and the personnel working near them.

2. So that the continuity in each connection can be checked by opening one of them and measuring ohms across the gap without risk to the operative, before re-closing them.

i) Logically one each will do; but, as earthing is a critical issue, one doesn't want to take a chance and hence two are provided, just in case one fails. The probability of both failing are very remote.

ii) ELCB setting has nothing to do with the i European practice is 10mA.