Originally Posted by nbhybrid
couldn't you come down the same hole as your vent pipe? Generally the holes in the roof are a lot bigger than the pipe to aid in assembly. Might save drilling a new hole
I looked at running the wire down the same hole that the black water vent uses, but I'm not sure how to secure the wire without damaging the vent pipe cap. Large wire will not slip through the available space.
What I think that I'll do I is to use a waterproof electrical conduit elbow made for 3/4 inch pipe. I'll cut off most of the elbow so that only the base and one connector opening remain. Then I will cut a hole the size of the connector in the combiner box. With the combiner box over a new hole in the roof and enough dicor and screws it should be waterproof. The connector will extend down into the hole and be glued to a 3/4 inch pipe that will extend down through the hollow wall between the toilet and the bedroom. I'm not sure what I will do if there is any kind of brace in the hollow wall. Drilling a hole through it from up on top of the roof could be difficult.