Hook up cables

There and back

Hello to all,

We are so new to motor homing that we haven't even collected it yet. I'm sure we are going to have a steep learning curve! I would just like some advise re the electrical hook up. I am presuming it has waterproof connectors, but we want to travel to France
and I have seen a 2 pin adapter hook up cable to use over there. seeing as I would be joining cables, do I need a waterproof protection case to cover the joining of the cables? 

Thanks to all replys.