How exactly the cables are laid in your caravan | motorhome depends on the model and layout. What they all have in common, however, is that the cables for 12 V and 230 V must be laid completely separately. There are also separate fuses for both voltages in the caravan | motorhome. Most camping appliances are designed for 12 V. They obtain their electricity from a central distributor. All appliances should be equipped with their own fuses in the motorhome. It is always advisable to have spare fuses with you in case one breaks.
The distributor is usually located on the EBL (electrical block) together with the charger, cut-off relay and refrigerator relay. Most 12V consumers are also fused there. A common place for the 230V fuse box and other electrics is in the wardrobe, under a bench seat, the kitchen unit or even in the vehicle floor. In addition, multiple replacements should be available for all fuses that are required!