I must apologies i was thinking of rcbo's with functional earth leads. I agree that an RCD test button does not require a functional earth.What we are telling you (not merely suggesting) is that pressing the test button on an RCD will (if the RCD is non-faulty) result in its tripping, regardless of any consdierations of earthing, or the absence of it.Gents, just for the record are you advising the OP that the RCD should not be tested ? Are you also suggesting that if they operate it has no bearing on the situation and of so, what is the purpose of installing RCD's ?
The only exception is some RCD sockets, the test buttons of which appear to introduce an L-E leak in order to test RCD functionality. In all other cases (like the RCDs you find in CUs etc.), pressing the button connects a resistor between L on one side of the RCD and N on the other, thereby creating an L-N imbalance which causes the RCD to operate - 'earth', or 'leakage to earth' does not (and could not, in the absence of an earth/CPC connection to the RCD) have anything to do with it.
Of course householders should test RCDs (with the test button) to make sure that they function in response to an L-N imbalance, but that tells us nothing about the presence, absence or quality of an earth. In contrast, an electrician's RCD testing kit usually does introduce an L-CPC leak, and hence will fail to trip the RCD in the absence of an adequate earth.
Kind Regards, John
I standby everything else i have said, it is impotant that the OP understands that the rcd will operate in the event of a fault even without an earth.
Regards,
DS