A friend owns a farm and offers tent camping pitches as a sideline.
They wish to provide a limited and safe ELV supply to such camping pitches, for lighting, charging of electronics, and other low power uses.
Does anyone see any flaw in my proposal which is as follows.
For each pitch provide a 13.8 volt DC supply, current limited to 8 amps, this obtained from a DC to DC converter contained in a locked enclosure. Output via 2 core heavy duty rubber sheathed flex terminated in a plastic box on which will be mounted 3 automotive type cigar lighter outlets. Small green LED pilot lamp to show that the supply is on. No overcurrent protection required as DC to DC converter is current limited. No means of isolation provided at such a low voltage.
When not in use the trailing leads and the outlet boxes will be stored under some form of small shelter.
When in use, outlet box in users tent.
Cable size selected to give a minimum of 11 volts at full load.
10 camping pitches, 5 post mounted boxes, each containing two supplies.
"mains" input to these DC to DC converters to be 3 wire DC at 26/0/26 volts nominal, which could be up to to about 30 volts actual. Obtained from the main RE system at the farm buildings.
Distribution via 10mm twin with earth cable, overhead and well out of reach. Each post will also have a small amenity light to give low level area lighting.
The main 3 wire DC system has the center wire earthed. The CPC in the 10mm twin with earth cable will be used as a current carrying conductor, but only for the earthed center wire.
The 13.8 volt circuits derived from this system are isolated from earth.
