DC grounding issue (solved)

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DC grounding issue (solved)

Postby les45 » Tue Oct 31, 2017 4:11 pm

One of the minor issues after the first camp with my new pop-up project was the need for a better location for the switch to the overhead DC light over the bed. I kept the two original overhead DC lights which have their own built in switches. One of the lights is over the bed so accessing the switch involved standing on the mattress. I decided to install a simple toggle switch in the circuit to that light at a box that houses the terminal strips which distribute the DC power to those lights near the center of the cabin. This would be easily accessible while standing in the center galley area. I have dedicated grounds to all my DC fixtures so I figured I could simply install the switch into the ground wire inside the box since it was a little easier to access. After installing the switch, the light came on in the on position, but it dimmed slightly and stayed on when I flipped the switch off. After changing the wiring so that the switch was in the positive lead, the switch worked as it should. It took me a while to figure this out but it finally dawned on me that, even though I had dedicated ground wires, they grounded to the frame of the light fixture. The frames are mounted over aluminum cladding which forms the ceiling of the cabin. Therefore the frame of one light is electrically connected to the frame (and ground wire) of the other fixture because of this. Apparently, the cladding was providing a path for the light to be grounded even though I had cut the dedicated ground wire. Another lesson learned.

The toggle switch was installed in the left wall of the box so it appeared to be easier to cut the white ground wire on the bottom left to connect the switch. After that didn't work, I ended up connecting the black positive wire to the switch.
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