what causes earth leakage?

[ExArmy]

testing a house today before I put RCD protection on it and i got 300mA earth leakage. appox 100mA from the sockets, 180mA on the downstairs lighting circuit, then 20 odd mA accross the rest of the circuits.

I had a poke around the downstairs lighting circuit, couldn't see anything obvious, did R2 tests at all points (OK), did IR test and it was in the region of 650MΩ L-N, L-E and N-E.

as for the sockets, 2 chest freezers that are older then me are the cause of 50mA between them, rest is unnacounted for?

what causes this?

 

[GLENNSPARK]

Naa naa ne naa naa......... my mft will measure earth leakage........

 

[1shortcircuit]

Naa naa ne naa naa......... my mft will measure earth leakage........

Okay then Mr Smarty Pants, I guess you ought to be posting a link to your model of MFT for future onlookers

:thumbsup

 

[telectrix]

Naa naa ne naa naa......... my mft will measure earth leakage........

when it'll make the tea/coffee, then i'll be impressed.