FI switch does not trip

I have completely re-laid all cables in a flat (built 1875, electrical approx. 1970) in 20mm conduits with 3 cores. A new grounding with equipotential bonding and grounding rod was installed by a professional company about 4 years ago, and a grounding cable was pulled into each apartment. The fuse box was equipped with a 30mA RCD for single-phase alternating current and 5 circuits (4x16A, 1x13A). After everything was laid and wired, the grounding and all circuits in the fuse box were connected to the grounding busbar. Since only one phase is fed from the hallway distributor to each apartment (cooking and heating is done with gas), I first connected phase and neutral to the RCD, and then bridged to the individual circuit breakers. However, during a simple test (connecting phase to grounding using a test lamp), the RCD does not trip. Could this be due to faulty house grounding? The tripping was checked immediately after the circuit breakers in the fuse box.

Hello!

That can of course be due to a faulty grounding, yes. If there is a short circuit, the current flows off via the PE. The FI now notices that the same current is no longer returning on the neutral conductor N as was previously sent out through the phase, because the current flows through the PE. And then it trips. But if no grounding is present, the current cannot flow off via the PE.

I would have an electrician check the wiring. You can relatively quickly find out with the right measuring devices whether an FI works or not, and where the fault lies.

Best regards

Flying-Spark