When waterproof fitting are needed, the best place to look is the marine industry. With a number of antennas and powered items mounted on our roof rack I needed lots of wiring access. To accommodate the high number of wires I chose to install 2 roof wiring ports. The part that I used is from Blue Sea Marine. The CableClams provide a water proof port that can be reused.
Blue Sea CableClam
I mounted one cable clam at the front of the rack and one a the rear.
The cable clams have a base that is attached to the sheet metal using a rubber gasket.
There is a rubber plug that I drilled out doe the wires. This plug is then clamped down using a top ring that is attached to the base with 4 screws.
Cost: $18.00 each
Time: 45 Minutes