I've just bought a 4th floor apartment in an old (1820) building in Spain. Neither my apartment, nor the building as a whole, has any earth circuit. 

I'm looking for **practical, technical** advice on what steps I can take to minimise risks of injury or equipment damage caused by this arrangement. Longer term, can anybody suggest what installing a building ground circuit would entail? My apartment backs onto a small service courtyard (called a "patio" here), so for example, it's relatively easy for me to run a cable to ground level. 

update...

The service input goes to an old Siemens schutzschalter which is labelled as 30mA. The output of the Siemens goes to a single 20A circuit breaker which then feeds all of the lights and sockets in the apartment. 

Pressing the Test button on the Siemens has no effect, so I'm guessing that's not giving me a whole bunch of protection. Since it's wired directly to the supply, it will take time to organise the electricity company to intervene. Therefore, is it reasonable for me to add a second RCB (<https://www.bricodepot.es/productos/electricidad/proteccion-electrica/proteccion-modular/diferencial-bipolar>), alongside the breaker to provide the RCB protection? There is ample space in the consumer unit for it.

I should also explain that the whole apartment is scheduled for renovation, including rewiring. Thus I'm looking for what I can do quickly to address any safety issues for the interim.

Existing

```
mains ===> Siemens ===> 20a breaker ====> lights and sockets

```

Proposed

> 
> mains ===> Siemens ===> New RCB ===> 20a breaker ====> lights and
>  sockets
> 
> 
>