You can download the installation instructions here:
http://www.barkermfg.com/auto%20drain2.pdf
They call for an "UNSWITCHED 16 GA WIRE" to power the device.
I have not installed one, but if it were me, I would run a "dedicated" 16 ga wire from the fuse panel in the power center or install an "inline fuse" in a 16 ga wire from the battery. With that device, if it should "stick" or get "hard to open" it will be drawing quite a bit of DC current and should be on an individual, fused circuit.
Take pictures and let us know how the install goes. A lot of us are faced with the same "dumping problems".....
Good Luck