Since space is so tight in a class B camping van, each vehicle presents its unique challenges. I've included some photos of my installation on my 2003 Chevy Roadtrek 190 Versatile model.
I had to remove the toilet and the bathroom floor board to allow easy access to the space beneath for wiring. Surprisingly, the removal process was very simple and took all of 10-15 minutes.
This is the space to work with. I covered the blackwater tank drain with a plastic bag to avoid dropping anything into the tank.
This is my finished wiring job. The main 4⁄0 cables go through the wall on the left to the inverter. A cutoff switch is installed so I can easily reach it once the toilet is put back in place. Also seen toward the back of this space are the two AC cables running within a 1⁄2 inch split wire loom.
The cylindrical object houses the 300 Amp T-fuse. This protects the metal parts from coming into contact with anything. I made this up so I could easily loosen the clamp and slide the housing off the T-fuse in case I needed to change the fuse for some reason without having to take the toilet out again. This is made up of a rubber plumbing 1 1⁄4 inch PVC pipe connector with an adapter on each end that restricts the opening enough so the fuse assembly can't slide out. You can better see the cutoff switch in this picture too. I had to modify the plastic housing of the switch so the big 4⁄0 cables would fit into it.
This is where the positive and negative cables pass through the van floor. I used a 1 inch cable strain relief through each hole to hold the wires firmly in place and to protect them as they passed through the floor. You can also see the flexible split wire loom covering each of the battery cables. The 8 AWG green ground wire is seen with a crimped lug and screw grounding it to the van metal floor. The telephone type cable is the excess wire lead for the battery temperature sensor, which then runs with the negative battery cable to the rear battery compartment.
Finished project with bathroom floor compartment door closed
Bathroom floor compartment door opened, revealing the shutoff switch for the positive battery cable going to the inverter. You can also see the telephone type cable just above the switch which I ran along the front left corner of the bathroom wall up to the inverter display panel. I secured this cable using white silicon caulk so you can barely see it even if you look for it.