House Tripping - old wiring

HI All,

It's gonna be a lengthy one, so please bear with me. I live in Malta.

I'm a new DIY man with basic circuit knowledge from school. I recently moved into a house with very old wiring from what i can tell. The modern type consumer unit is non existent and it appears that the whole house is on a single circuit.

The power is coming (from mains outside) to an pre-historic fuse box with a single main switch - a massive ON/OFF switch with a fuse the size of a fist and a wire within thick enough to survive any surge in form of a black and red wires (red being live, black neutral - theres no earth). From there, sparkies from the times of middle earth have wired the L and N (no E) to respective holes of a semi-modern main switch & RCD combined.

The switch comes 3-part combined (double main + single RCD). Wires are going into the RCD from the aincent mains and going out of the new main to the rest of the house. I hope by some miracle you can imagine the circut & switch.

The switch is a 63 one instead of the Malta standard 40. (model DS652 - Brand ABB)

Thats all i have access to.

Now,

Few days ago the cooker (i discovered) kept on tripping the RCD which ten continued to trip even after i physically disconnected the cooker from the socket. After a couple of hours the RCD miraculously worked on its own wihtout further influence (cooker remained disconnected). Thats a first ?? - any ideas how come? It tripped again and i decided to change the RCD+main and repace is with new single RCD in same value.

Now the L and N wires from the aincent main switch go into RCD and from there to the rest of the hosue. Ireplace with same 63 value RCD, but modern.

This worked fine for a few days with everything on, stable. Great.

I decided to change some light fittings today. I switched the RCD off myself, stupidly instead of switching off the mains. I cut the wires going to the old style 'candle looking' wall lights and realised both wires are black.

I needed to check which was the live one so i went to switch the mains back on.

Now it wont turn back on. Its tripping the house continuously. I separated the cut wires. Connected them to terminal connectors. I separated them. I switched EVERYTHING off.i mean evrything - cooker and al;l otehr appliances are off from the walls etc. (cooker was working fine after being repaired few days back by a technician).

point of this long story is THE WHOLE HOSUE IS 100% OFF and the RCD is still tipping.

I bypassed it and hooked mains to mains and tested that all is off - confirmed. im currently online due to not having a functional RCD.

does anyone have ANY idea what could possibly be causing the RCD to trip with all off and the wires a cut insulated separately with insulation tape?

I have no ideas left.

Any train of thought is much appreciated.

Thank you.

Why did you bypass a safety device (RCD)?

Sounds like your RCD has developed a fault, try a new one. On another note, it sounds like you should get a professional in to check all your wiring and make sure it is safe, and perhaps install some sort of earth for you.