How to detect earth fault error occuring at house, industry, office etc?

Thank you for Invitation

I don't Know how but you can use Avometer to detect if there is any Current 

There are Testers available in the market, which are like a Donuts CT powered by a 12V battery. You can check the continuity of the ground system using them. Generally if all is good and the grounding system is connected to the System ground or Earth, it will show 0.7 Ohms value. If not then it is going to give a higher reading and that is an indication that your grounding system is not connected properly and you have to take remedial measures.