RCD tripping when circuit off

[bigwedge]

Having switched the ring main circuit off at my newly pro-fitted CU, I cut through the T&E wiring on a circuit I'm working on, and the rcd tripped. Now the circuit was definitely dead (I'd touched all of the wires without killing myself!).

How can this be possible - and I assume I need to get the "expert" back in to correct this?

[sparx]

Hi B-W,
no prob this is normal!
when you cut the 'dead' circuit you would have only 'killed' the live conductor by switching off the MCB,
when you cut wire it connected N & E together, if any other circuit was taking power ie a light it would have given an unbalance to RCD which does its job & trips, bit of a pain but not a fault,
regards SPARX