Re: 12/24v socket outlets
Cigarette Lighter type sockets are also not very child friendly (or possibly, too child friendly). I would tend to avoid recommending them in areas where children are unsupervised. Using slightly less than standard UL approved AC connectors are designed to be (relatively) resistance to children's figures (child with wire, all bets are off).
Depending on the load (match current rating with that of the load)--I would suggest using a non-120 VAC standard AC sockets available from the hardware store--Like twist lock sockets and well labled (some are even available in Orange or other colors to attract attention to the differences). Then you can use standard house wiring techniques (boxes, covers, good UL cordage connections available, ROMEX, conduit,etc.) for your DC system.
As always, upstream fusing/breakers are very important in any distribution wiring scheme. (you need to make sure that the wiring is heavy enough to both trip the circuit breakers without damage, and the resistance of the run must be low enough to ensure that the surge current of a dead short will also trip the breaker/fuse).
20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.