12VDC Wiring in cabin

Discussion in 'Off Grid Living' started by kckndrgn, Mar 11, 2014.

  1. kckndrgn

    kckndrgn Monkey+++ Moderator Emeritus Founding Member

    I'm still in the layout planning, but I need to know what size wire for internal wiring of 12vdc items.

    Items include 12vdc LED lights (3.2 W max that I have right now) and an RV ceiling fan (12W per the manufacturer).
    I'm looking at 4-6 light sets (used to light the area you are in not the entire cabin).

    The cabin is 14' x 20' and the "pig tails" on the lights I have are 18awg wire. Something tells me I need to run something bigger than that. Max run length would be no more than 34'.

    I was thinking of running possibly a 10awg wire as a tap off of that, but then figured I'd get a DC fuse block and make runs just like traditional AC wiring.

    I will also have some 110 outlets run from a fuse panel for tieing into the inverter and for running on generator.
    Thanks in advance!
  2. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    Up here, (Alaskan Bush) we mostly use standard #12 Romex, and make things just like AC, as most places, eventually, convert to AC and Inverter/Battery Banks, as they progress into getting their places Setup.... That way, when you do convert, you can just Pull the FuseBlock, and add a Breaker Panel, and you are ALL Ready to go.... #12 is good for 15 Amps, out to 50 ft. (15A*12V= 180 Watts) per leg of Romex)
  3. Cruisin Sloth

    Cruisin Sloth Special & Slow

    I agree , If all wiring is exposed , use 12awg shielded BX style Or with Plastic PVC to keep it all in semi code , Proper switch covers & boxes .12 Volt DC plugs are very special , Marine type are pricey & cheaply built Till your buying Amphenol style . !2 volt car vac's & other such toys ( tunes , Car sound etc) , anything that will come later so have a separate circuit for that also . I looked after a house for a while , all 12 volt , solar , dogs , chickens , HOUSE !! while the Dad & Mom were in the city having a complicated birth . I learn't lots ..
    Yard Dart likes this.
  4. Yard Dart

    Yard Dart Vigilant Monkey Moderator

    I agree with the other guys, don't go less than #12 since that will allow you the flexibility to run various power systems and not present a fire danger.
    AmericanRedoubt1776 likes this.
  5. kckndrgn

    kckndrgn Monkey+++ Moderator Emeritus Founding Member

    Awesome info, thanks all!
  6. Dunerunner

    Dunerunner Brewery Monkey Moderator

    A 12X20 cabin. Are you going to stay 12 VDC? I run A Red and Black 2/O welding cable the length of the cabin from my 12V Source. Then I'd stake my #12 DC runs off of that DC Buss to the lights and outlets. Leave enough at the opposite end of the cabin to connect another 12VDC Source of the same size, voltage and ampere hour capacity. Want to add Solar, just add the proper size Charge Controller anywhere onto the DC buss.

    As a note, building inspectors are usually not real knowledgeable of DC circuitry and what I have presented is probably so out of code it would never pass. All connections to the buss should be silver soldered and properly insulated.
    Mountainman likes this.
  7. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    Big wire is expensive... When we have straight runs of Low Voltage, High Current DC, we use 1/2" Copper Pipe... It comes in 100ft Coils and you just drill 5/8" Holes thru the wood and use the space between the two runs as the insulation. When you need to do a tap, you just squash the pipe flat, and drill a 1/4" hole and Bolt on a connection. Works for "Me" .......
    Oddmar, Dunerunner, oldawg and 2 others like this.
  8. -06

    -06 Monkey+++

    DC builds up heat. Old "Delco Remi" home units used ceramic insulators to keep all wires from contact with any wood. Am with BT on using 12 gauge wire. That way you can convert to AC w/o rewiring. For hot water heaters/AC I would use 10 gauge.
    Yard Dart and chelloveck like this.
  9. BTPost

    BTPost Stumpy Old Fart,Deadman Walking, Snow Monkey Moderator

    DC doesn't build any more HEAT in the conductors than AC would at the SAME Voltage. Heat comes for I2R Losses, and they are the SAME for AC & DC. The issue is that 12Vdc Requires a LOT More AMPs (10 times) for the same Power Transfer (Watts) than 120Volts and that causes more I2R losses in the same size wires on Power runs. This is why #12 wires can only supply 180 Watts @ 12Vdc and 1800 Watts @120 Vac. ......
  10. Cruisin Sloth

    Cruisin Sloth Special & Slow

    depends on code & area , plus a 220 VAC has 7 different styles . IBEW also dude here ! ..
    You can buy the 12 Volt DC plug from China ( Poohlo - Tang , spit blaaa) [Get over it , we don't build FA anymore ] that is a standard in India , Socket & plug is like 4.50 USD each . E-bay it & open the filters & clean the e-bay cookie crap
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