As stated earlier, ignoring the onboard TEST button for a moment, unless an RCD can be verified with an external tester to simulate a fault,
and the RCD/GFCI performs reliably with consistency as per it's time/current specs (and not just a couple of 'lucky' trips
)
then OP Fergo is wasting money on a false sense of security buying into an RCD in a situation where it may/might/won't/ work, or all three together
As it is, even with an RCD in place in a properly grounded system, if I'm playing 'risky business' with electronicals
there is my own portable fast trip 10>15ma RCD, or RCD/MCB combo close by,
so Murphy can stay on holidays and not bother me with cheap travel offers to hot places
It may be two RCDs to reset if a larger fault trips the main RCD too, but hey, still better value than post zap hospital therapy
or zapping the relatives with a funeral bill
FWIW, you only have to spend maybe one weekend to assemble all the generic bits needed get the safety thing right ONCE,
to save you and your gear MANY MANY times.
It's actually fun doing it, testing the lot just to see and know what the outcomes and limitations are,
and realize after a few trips
and sort of controlled BANGS! or pending snafus that it's not so predictable as you thought to make a system idiot proof.
Cheap fast blow inline fuses, even no name knockoff/fakes? (pre-test a couple first!) rated just above the expected current draw,
will save you LOTS of money on blunders that are guaranteed to come knocking.
I've got an assortment from 100ma up to 10amps, and the best $20 investment I spent years ago.
If it saves even one cheap multimeter or project or repair, you just got $20 back and the rest
An isolation transformer (or three..
) with switchable modes of earth/ground isolation is a great tool, but not for those unfamiliar with those modes.
Still, a proper wired 'medical' style isolation transformer is a good bet for 'some' isolation and interference/noise from the mains,
even though the earth/ground and neutral output are bonded internally.
I use those whenever I can as they will only pump out whatever power their limit is, and some expensive types will regulate and current limit on an overload or dead short.
But all that stuff is sort of useless unless you've simple PPE eyewear/face shield, gloves and rubber soles,
A bucket of sand, fire blanket and fire extinguisher wouldn't hurt either and won't break your pocket
I keep all that stuff in one flaky carton box, which saves on looking around for the bits, and doubles as a traveller too
Stay safe and best of luck to OP with the new scope