Turning on the AC power to my water heater requires turning on the circuit breaker located in the converter box near the floor and I was looking for something more convenient like an AC switch with a pilot light. I found a Leviton 5618-2A Decora switch on e-Bay for a good price. It was "new-old" discontinued stock.
The space next to the access panel above the converter looked like a good spot. Note, some idiot keeps leaving the converter door open to trip over ..... oh, that was me ....
There is 3 1/4 inches space here. The masking tape marks the edge of the access panel for the shower valves.
Using masking tape, I marked the far left edge of the available space and drew the outline of the "old work" plastic box for mounting the switch.
Oh, yes .... someone had to put the grey tank vent back there! There is 2 inches from the outside surface to the pipe. I found a shallow box that is just over 1 inch deep.
Since a jigsaw would no doubt cut that vent pipe in half, I used a "Oscillating Multifunction Power Tool" from Harbor Freight with a plunge blade to cut the opening. (Remember, it is always easier to make a small hole bigger that make a big hole smaller!
) The box just fits .... after some cutting.
With the box and switch and cover plate in position.
Next I removed the water heater wire (AWG 14/2 with ground) from the breaker and pulled it back to the switch and ran a 3 foot wire from the breaker to the switch. For pilot light type switches like this you have to run a neutral (white wire) to the switch as well as a ground so I joined the 2 neutrals outside the shallow box and ran 1 neutral and 1 ground into the box
The pilot light is not all that bright.
Note: that black wire hanging there goes to the water heater, I connected that later with the breaker off.
Often when camping we like to switch off the water heater, which is under the head of the bed. This will make it easier on my old knees and back.