RCB keeps tripping

[JohnW2]

Why cannot this be due to simple mechanical movement of previously separated cables/ terminals, when operating the switch to the off position, moving a line cable/terminal to touch and earthed part? For example, badly sheathed CPC at DP switch.

Not impossible, I suppose, although such a scenario would surely be likely to result in a bang and operation of an OPD, rather than just an RCD tripping?

Don't forget that we're talking about a phenomenon which apparently occurs repeatedly every time the switch is moved to the off position. If L/CPC contact was occurring every time, one would surely expect something more dramatic than an RCD trip to occur on at least some occasions. I would think that there would have to be some subtle twists to what you suggest for it to be a likely explanation of what the OP is experiencing. To consistently and repeatedly get a transient L/E path during swith-off which was <~7.67 k&#937;, but not very low impedance, would be pretty difficult! Having said that, any attempt to speculate as to what may be going on seems pretty hard to believe, so .....!!

Kind Regards, John

 

[EFLImpudence]

It could be N-E irrespective of the switching procedure.

Just as unlikely though, of course, if only when switching off.

 

[securespark]

... but, as I have said/implied, such a proposed mechanism seriously stretches my view as to what is credible. In particular, I find it almost impossible to believe that anything approaching 30mA would travel through such a path.

Perhaps stretching that credulity further, maybe there is already a certain amount of leakage being picked up by the RCD and this just tips it over?

 

[JohnW2]

It could be N-E irrespective of the switching procedure. Just as unlikely though, of course, if only when switching off.

True. As you will realise, I was responding to what Thripster had literally suggested (L-E contact).

Kind Regards, John

 

[JohnW2]

... but, as I have said/implied, such a proposed mechanism seriously stretches my view as to what is credible. In particular, I find it almost impossible to believe that anything approaching 30mA would travel through such a path.

Perhaps stretching that credulity further, maybe there is already a certain amount of leakage being picked up by the RCD and this just tips it over?

Yes, I almost suggested that myself - but the more 'co-incidental' factors one brings into the equation, the more does that credulity get stretched

Kind Regards, John