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  1. #1
    Join Date
    Oct 2011
    Location
    michigan
    Posts
    2

    Default low voltage home

    Has anyone ever examined low voltage DC for a hole house at new construction? Like 28 volt DC.
    Low voltage could be less hazardous and with led lighting more efficient. Most appliances operate on low voltage dc which has to be made from 110 ac why not cut out the middle man. only use ac for distance transmission. I know Tesla vs. Edison!!
    Last edited by par48; 10-01-2011 at 12:16 PM. Reason: correct an ommision

  2. #2
    Join Date
    Dec 2007
    Location
    Tennessee
    Posts
    1,745

    Default Re: low voltage home

    There are books on the subject at your library. Most use 12vdc where there are a lot of appliances available from the recreation vehicle market. Not much available for 28vdc though.

    Mostly people that build these systems have them for emergency lighting during power outages. Some did it for cabins and homes that were too far off the grid to get good old AC.

    When you use 12vDC instead of 110vAC, you need much larger wires to carry the necessary current if you run a serious appliance, like a small refrigerator. The cost of this wiring must be considered. Most 12vDc appliances are small for this reason. You will need gas for your stove and heating. If you need AC as well, you may need to get a propane powered central heat and air. 12vDC won't cut it.

    It's really hard to beat 120/240 VAC for a house.

  3. #3
    Join Date
    May 2011
    Posts
    251

    Default Re: low voltage home

    Sounds like spending dollars to save pennies.

    Ultimately most appliances are designed for 110VAC. The extra cost and reduced availability of appliances and devices will offset any gains. TO maintain resale value, you;d need to run doth voltages. Otherwise, good luck on your appraisal and getting a bank loan. It would be similar to building a 2500sqft 1 bedroom home.

    AS mentioned above. Wire size increases dramatically. For larger appliances, it becomes prohibitive. Even a small 2 Ton AC for example might need it's own 100Amp circuit.

    Finally, I'm not sure how building code apply here.

    Ultimately, there is a reason AC was selected over DC 100+ years ago. The advantages are still there in transmission and user safety.
    1925 Two-Story Stucco Beaux Arts Neoclassical

  4. #4
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,803

    Default Re: low voltage home

    First I know of no 28 volt DC appliances, lights, etc. available.
    Converting 120 VAC to 12 VDC will be expensive to do for more than one appliance. Inverters operate at about 70% efficiency, that means a hough loss.

    Very accurate wire length measurements are need for DC circuits because of the losses caused by resistance per foot. Multiple sizes of wire would be needed or extremely large wire through out. A 5 volt drop in 120 VAC circuit is insignificant but a 5 volt drop in a 12 VDC circuit isn't. Wiring would probably be 5 to 10 times more expensive than wiring for 120 VAC.

    It is extremely expensive to build a supply to provide enough 12 VDC to power a home or even a significant part of the home.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

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