I am not much of fan for drilling through the RV ROOF for anything.
I have used the PVC ELECTRICAL BOXES (LOWES) and drilled a large hole in the center of it. Then I can mount this box to the side wall close to the roof and hopefully come out inside a ceiling mounted cabinet.
The PVC Electrical box can use a weather tight lid and uses several combinations of PVC TUBING connections into the Electrical box.
This is great using inside cabinets to go thru the floor also... The Electrical box seals real good using RTV sealant etc...
Food for thought...
Roy Ken
