Anyone ever drilled through the floor?

Hi, I'm in the process of installing a solar panel on the roof and I was planning on running the electrical wiring through the roof in the space behind the shower (rpod 177) and mounting the charge controller there (the wall where the other sensors and switches are by the door), then continuing the wiring down through the floor and joining up with existing wiring over to where the battery is.   I've installed a LiPO battery so I've also got a battery monitor mounted on that wall as well.   But this means I need to drill through the floor.   Anyone ever done that?  How hard is it?  What do you recommend to plug up/waterproof the hole after I run the wiring through?   There's the existing hole with the wiring but it's under the shower pan and I can't get to it, plus it's not big enough so I was just going to drill another hole.   I've installed a small access door near the floor on that wall so I can get to the floor and have already installed the battery monitor but the wiring is just hanging down.  I've not put the solar panel on yet. I've fairly confident about everything except drilling that hole as the floor is rather thick and I know there's a lot of layers and I want to make sure I properly seal it up after the wires are through.  So again, any thoughts/advice would be appreciated.  

I have a 2019 179 and have installed solar on the roof and did some extensive rewiring of the 12v system on the trailer.  The solar system seems to be holding up well after 5 seasons of camping.  Regarding your question of putting a hole in the floor for some wiring you are adding for your system that you are installing, I elected to increase the size of the hole already in the flooring that Forest River had put there. It is my understanding that the floor construction is the same as the walls.  That construction of the flooring going from top to bottom is there is a layer of lauan (1/4 inch) then 2 inches of foam insulation followed by another layer of lauan and finally a black fabric vapor barrier visible from the bottom.  Also there is a 2 inch aluminum frame work incorporated into the flooring.  Both layers of lauan are glued to the insulation/frame work. You can search the r-pod trailer construction from older posts on this web site which have you-tube video clips of the construction process.

Thanks for the insights.   

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