RCD

[empip]

Having said my old RCD adaptor is working ok... I fished out a brand new spare (different make).
Plugged one into the other, the combined pair into socket.
Trip button test the one nearest socket, it trips but not the piggybacked adaptor.
Reset both. Trip button test the piggyback, both trip together.
Swap the two, same result.
For an average householder, is this a neat little test?
I am thinking the outer 'piggyback' adaptor with 'press to test' actioned, represents an appliance with a fault, independent of the second (closest to socket) adaptor's test button.
Reasonable assumption or not?
-------- Edit
Nah, that was rubbish.. see next post.

 

[Lectrician]

The test button does not actually cause an earth fault - it imbalances the internal coil. Pressing the test button on one plugged into the other is actually unlikely to cause the other to operate, so I am suprised this did for you.

 

[empip]

The test button does not actually cause an earth fault - it imbalances the internal coil. Pressing the test button on one plugged into the other is actually unlikely to cause the other to operate, so I am suprised this did for you.

You are of course, correct. I had it backwards..Tripping the outer has no effect upon the inner.

It was the nearer to the socket which caused the outer to trip - The adaptors are 'non-latching' they trip on power loss.. So the outer one was always going to trip with the inner breaking.