OP
domestic spark
You can switch off locally but you can't always be certain that every load is isolated, that's why the recommended procedure is on the outgoing terminals of the device with loads disconnected.
The capacitors etc. don't actually make the RCD/RCBO trip any later but as wirepuller says, they 'trick' the rcd tester into displaying a higher trip time.
so basically disconnect these items out of the loop for the benefit of thetest.
however only if your not achieving your times!
i ask this as ive never had this problem testing!