How to find Low Insulation (Earth Fault) in a live circuit?

[wetholedigger]

Good day fellow Electricians,

I am just new in this field, I am currently working on a ship. Now, my problem I am having an earth fault on our 3Phase 220V. If only I could switched OFF all breakers then it would be easy to find this earth fault but the thing there are some essential loads that cannot be switched OFF.

How is it possible to find the earth in a live circuit? There are 20 machineries attached and sharing this 220V supply. Using the earthing lamps, when I pressed it, line "R" is off but "S" and "T" are on.

Hope you can help me. Thank you so much in advance.

 

[Knobhead]

How do you repair a fault on a live circuit?
Get a second fault and you’ll soon find out how critical the loads are.
An organised shut down is better than an enforced one.