rcd ac type

[moglee]

does an rcd need a earth connection tt system to operate properly,
or will mit not operate at all
also does the imbalance travel to earth,

i have a rcd tester i bought pretty basic detects earth and phase neutral reversal etc.
you plug it in to a pc outlet then you can also test the rcd by causing a 10ma to 30ma fault it works when there is a earth present!! not when there is no earth
what is it actually doing

 

[winston1]

does an rcd need a earth connection tt system to operate properly,
or will mit not operate at all
also does the imbalance travel to earth,

i have a rcd tester i bought pretty basic detects earth and phase neutral reversal etc.
you plug it in to a pc outlet then you can also test the rcd by causing a 10ma to 30ma fault it works when there is a earth present!! not when there is no earth
what is it actually doing

An RCD does not need an earth connection to function. It operates on an imbalance between live and neutral. The unbalance current usually goes to earth (through your body perhaps) but it could also be a leakage to another phase or by bypassing one side of the RCD due to a borrowed neutral from an unprotected circuit.