Low Voltage House Wiring
 

Does anyone have any experience with wiring a house with 12 volt wiring? I'm thinking of doing that for a cabin along with solar power.

:shine:

Re: Low Voltage House Wiring
 

While I'm not participating in your discussion (likely nada to add atm), I'll post a link for some interesting light bulbs.

12 volts, fits an ordinary household fixture... fwiw.

http://cgi.ebay.ca/12-Volt-Light-Bul...efaultDomain_0

Keep amps in mind when wiring: Watts divided by volts = amps.

Re: Low Voltage House Wiring
 

Would suggest 24 or 32 volt dc for lighting; more efficient,

Especially if you use LED's.

You are SOL for anything which requires an electric motor, i.e.

Washing machine, dryer, dishwasher, well pump etc..

Equally SOL for electric stoves, furnaces, heatpumps

Und so on.

What are you trying to accomplish?


scyth

Re: Low Voltage House Wiring
 

More volts would lower the amp draw which would in theory be easier on the wiring. Amps are what melts things an causes grief. Yeah, you need to decide exactly what you're powering.

Cabin got TV, appliances, etc or just lights?

Just park your truck by a window... ;)

Re: Low Voltage House Wiring
 

I want in on this thread as I too am working on something like that. I am looking at wind, mini-hydro, and solar to charge the batteries. I heard that 6 volt deep cycles are great to use so I was thinking about getting 8 and hooked together in parallel and series with 24v.

Any experience and pointers is greatly appreciated!

Re: Low Voltage House Wiring
 

Yep, make sure you size your wires correctly and have proper circuit protection. The problem with electricity is you can do things wrong and it will still work and it may work for a long time just fine, until it starts a fire or bites you in the ass some other way.

Re: Low Voltage House Wiring
 

Well, this will be a test with a cabin first before possibly using with a house at a later date. A 12 volt system can be done without an electrician, and DC is safer than AC, especially 120 volts AC.

I think most appliances come in 12 volts or can be converted. Not as many options as with AC, but available, though sometimes expensive, like refrigerators.

I have a 12 volt TV (small 12").

An invertor can be used for something that may be too expensive, or not available in 12 volts.

Here is a link for 12 volt well pump for example
http://www.kansaswindpower.net/pumps,_submersible.htm

Re: Low Voltage House Wiring
 

I've got 12 volt in my RV connected to 2 rooftop solar panels, inverter/charger, charge controller, and 6 volt batteries...about all you can do with 12 volt is lights, teevee, stereo, water pump, fans/blowers and power the control panels on gas appliances like the refrigerator. The inverter will change 12 volt to 110 but it will draw your batteries down pretty quick.

Re: Low Voltage House Wiring
 

Just use 14 ga wire, as in regular house wire.

If you ever want to connect to the grid, or use a generator, you'll be wired for it.

12v will run on 14ga just fine....

Re: Low Voltage House Wiring
 

Most houses today are wired with 12ga, unless it's a lighting circuit, then 14 is sometimes used, depending on the number of lights on the circuit.

The lower voltage DC will have a faster voltage drop than the higher voltage AC, so a larger gauge wire is sometimes needed. All depends on the voltage, the amp draw, and the length of the run.

Re: Low Voltage House Wiring
 

i like 12 volt for lighting and for other purposes especially if it is only a small
cabin/trailer etc

i would have used it myself if i was doing it from scratch but my house
was already wired for 120/240 AC so inverters were the way to go for me.

some pointers for 12 volt use heavy enough wires to avoid as much as possible excesive voltage drop.
solder everything low voltage DC does not do well long term with twisted
wires or those quick clamps even crimp plugs have problems especially
if exposed to any moisture.
AC switches like you find in a normal home are not made for DC
and can actually fail very prematurely if used to switch DC.

most installers will recomend higher voltage solar/wind/generator battery
setups because of voltage drop problems with 12V long wire runs and
heavy loads and they are right to do so the money you can save in
wire buy going higher voltage could litteraly buy more panels or batteries.

but for a small low demand system you cant beat the compatability
and availability of 12V gear.

for use with 12v
lights are a good use
radio is a good use
12v tv and laptop are ok
water pumping is ok if pump is close to
battery bank and you dont have to raise the water
to high and you have minimal water demands.
water or space heating forget it.
refridgerator ok if built for 12v and efficient
coffee machines poor
microwaves poor
dishwashers,washing machines poor
toasters poor

Re: Low Voltage House Wiring
 

I wired my first house with14 gauge wire and ran it on an old 12 volt Trace 120vac modified sine wave inverter .I wired it the way an electrician typically would using branch circuits, this is a no no if you are not powering up the panel with 240 vac which in the past meant 2 inverters. It's ok to use one 120vac inverter(you won't be able to run any 220 appliances like a dryer) just be sure not to use any branch circuits, all circuits should be home runs back to the panel. Yes you can get away with branch circuits I did for 10 years until I read it was unsafe.

Re: Low Voltage House Wiring
 

I agree with scyth. Go for 24 VDC min, but 36 VDC would be better.

Re: Low Voltage House Wiring
 

24volt or 48, forget 36.....more products available for 24 or 48.

Re: Low Voltage House Wiring
 

Why not just skip all the trouble and use an inverter......

Re: Low Voltage House Wiring
 

My dad built a small dam in a creek by his gold mine and generated enough power with a 12v generator (the size of 2 car batteries) to power almost 600 watts of appliances for 3 people. All he had to do was walk out and switch on the water wheel.

Re: Low Voltage House Wiring
 

That's what I'm talking about in my posts, although I may not have made it clear enough in my last post.

Mozkill, hydro is by far the cheapest way to make power but we don't all have the luxury of a stream near us. Sound like your pops had a sweat set up and the beauty of his deal was he got power 24 hours a day 7 days a week.

Re: Low Voltage House Wiring
 

I did mine in both 120VAC and 12VDC. The 12 VDC was wired in 10 guage to minimize voltage drop. I chose 12 over 24 VDC because of availability of RV compnents and accessories.

The 120VAC is powered by generator and the 12VDC is powered by solar.
Most people just use an inverter.

Re: Low Voltage House Wiring
 

Electric fields are unhealthy to be around. Inverters are not anywhere near 100% efficient. They humm, too.

If you go with hydro, by all means step up the voltage. Have a battery bank and inverter at the hydro generator and run 120VAC to the house thus avoiding buying real heavy wires needed for low voltage.

Re: Low Voltage House Wiring
 

You can't go more than 30 feet with 12G on 12VDC lighting circuits. The florescent lights will fail.

Re: Low Voltage House Wiring
 

Uh, you can't really just pick a wire gauge and go with it.

You have to know the amp load, then pick the wire to match it.

You're right....14ga will run 12v, or ANY volts up to the rating of the insulation on the wire ( 600v for most "Romex" style house wire ), but the limit is the amperage.....which is 15a for 14ga wire.

The problem is, as the voltage goes lower, the amperage goes inverse for the same wattage.

Take a 60watt lightbulb as an example: Volts x Amps = Watts

or A = Watts/Volts

In a 120v system, A = 60w/120v = .5amps. You could run 30 60w bulbs on a 14ga wire.

In a 12v system A = 60w/12 = 5amps.....you could only run 3 bulbs !

And that doesn't even take into account the voltage drop, which when you use lower voltage, increases WAY quicker as a % of the total than when you go higher voltage......meaning, depending on how far you run the wire, you might only be able to run 1 or 2 bulbs....maybe NONE if you run a few hundred feet !


To wire the cabin in question:

Locate the battery bank as close as possible to where you are going to use it......build a battery box on the outside wall of the cabin ideally.....one to cut wire run distance, and two, to vent the box to outside if you are using batteries that off gas hydrogen when charging.

Then come right inside the cabin on the same wall, and mount a distribution panel. You can buy specialized panels and DC breakers from Solar outfits.....most of them are kinda high priced....or you can use a Square D panel and QO type breakers ( NOT "HOMELINE" TYPE ) which are rated for DC (48v max ) as well as AC. You can buy the panel locally, and usually the breakers as well.

From there, you can run your branch circuits, and as hoarder said, I'd use 10ga wire, and keep the runs short as possible.

If I were doing this, I'd probably run a dual system of low volt DC and regular volt AC side by side.

Re: Low Voltage House Wiring
 

Some interesting stuff here;
http://www.builditsolar.com/Projects...htm#Appliances

I think alot of DC appliances are available in 48V. Higher voltage is better as everyone says for a more permanent installation. 12v is fine for temp or very occasional use.

rest

Re: Low Voltage House Wiring
 

I pretty much stay out of these threads because I can't type fast enough, I have been 100% off grid for 24 years, gone through all the progressions from straight 12vdc then to 12 vdc inverted and to my present system of 48vdc inverted yes the ole house was quaint and cute but it was limited, if your willing to do without then it's not a problem, don't get me wrong even with a large 48volt inverted system you still make an effort not to waist power that's the nature of the game. My inverter is 94% efficient and resides in a Mech. RM along with all the breakers, meters and sub panel ,the buzz and electical fields are not a problem....btw if you were truly worried about electrical fields in a straight 12vdc system you would put a twist on all the + and - wires as they travel through the house. I have forgotten more than some of you know and there are others that are just just plain ole smarter than me but I have "been there and done that" and I would never go back to a non inverted system . And don't forget the inverter is a very effective and efficient battery charger when the generator comes on much more so than most any battery charger you can buy.

Yes I am aware of the OPs original question but I got up early and thought I would go on a long drawn out non-sensical rant :s1:


If I was going to do a little cabin where power requirements weren't the major concern I would probably go straight 12 volt, I have a system like that up the road about a half mile that my parents used to use when they came to visit. once you have lights and maybe a fan or two then your only other requirements might be a fridg and maybe a tv . The fridg is easy, go with an old servel or a 12 volt sunfrost and there's another I can't think of.

Besides the panels and batteries the most important thing in a simple 12 volt system is the battery state of charge controller make sure it has temp. compensation and if the meter is remote make sure the probe is attached to a positve plate on the battery bank and is well insulated ... don't skimp on the charge controller . The battery box is equally important in maintaining a constant temp,even though battery capacity at high temperatures is higher, battery life is shortened. Battery capacity is reduced by 50% at -22 degrees F - but battery LIFE increases by about 60%. Battery life is reduced at higher temperatures - for every 15 degrees F over 77, battery life is cut in half. This holds true for ANY lead acid battery.

Hoarder & Andy thanks for cutting through the mustard and answering the OPs original question in a simple straight forward fashion....something I'm not so good at ......my other problem is I can't type for squat, I'm a one fingered pecker:smile:

Re: Low Voltage House Wiring
 

My BO place is 12v all through, with a big 240v generator if needed. Gas stove, gas fridge. Heated by wood. A couple of small solar panels keep the batteries topped up, the electricity is mostly for lighting. Anything bigger I need to run and I start the generator up, which can also top off the batteries if required.

Re: Low Voltage House Wiring
 

You have more experience living off grid than anyone I know. The 12VDC was my decision because the cabin was not intended for a family and I don't watch TV or listen to music at home...ever. If I had an inverter system I'd mount the inverter in a basement or crawl space as far away as possible from where I would spend much time. I probably type twice as fast as you because I use BOTH INDEX FINGERS! I'm pretty fast but make a lot of mistakes, it's funny to see younger people do a double take when they see me get after the keyboard with those two pointers.

Re: Low Voltage House Wiring
 

You must be like me, I'm a high speed hunt and pecker.

But it works.

Re: Low Voltage House Wiring
 

Yes, I was refering to the AC wiring on most of today's homes. Some AC lighting circuits will run 14ga for the lights, but the rest will be 12. I personally prefer to run 12 even for the lights.

I was pointing out that 14ga would be far too small for most 12v or 24v systems.

Re: Low Voltage House Wiring
 

15 amp service requires 14 awg and 20 amp service requires 12 awg.

Re: Low Voltage House Wiring
 

That is correct.

When 14 gauge wire is used in a lighting circuit, a 15 amp breaker is used.

Re: Low Voltage House Wiring
 

LOW voltage needs BIG copper.
A 30 foot run with 14 gauge wire is NOT sufficient for 12 volt circuits, the circuit path for a scant 30 foot run including return path is a 60 feet. 60 feet of 14 gauge will look a lot like a resistor to a 12 volt battery, you will be wasting more power in HEAT with undersized DC wiring than if you had run an inverter and wired the house for conventional 120 volts AC power.
Minimum wire size for 12 volt in wall, lighting circuits is 10 gauge. that is MINIMUM.
consider using larger (4 or 6 gauge) feeder busses from the battery bank to the farther rooms in your house, then branching off from these junction points.
If you are just wiring up a small trailer, bus or cabin, 10 gauge direct runs will be okay.
Have you given any thought to what you will use for a DC outlet and connector?
I have been using 1/4 inch phone jacks for my motorcycle accesories, heated vest, battery charger, etc.
they are pretty durable, compact, and easily handle a steady 10 amps without heating up.
don't expect the cheap Xhinese versions to work well or last very long.
look for high quality Switchcraft or Amphenol connectors at a music or commercial radio supply.

Re: Low Voltage House Wiring
 

You have to use heavier copper wires to carry the current. You can get a 12V version of anything that runs on 120V, but the nuisance and cost of the copper is enough that you might prefer to just wire for 120 and use an inverter.

Re: Low Voltage House Wiring
 

Volts do not dictate wire gauge, amps do.

More volts will lower amps.

Conversely lower voltage will raise the amps which will require heavier wire.

Running a low voltage system implies either short wire runs and/or heavy gauge wire. Long runs will likely imply a need for slightly higher voltage at the source to compensate for losses at the end. Multi-tap transformers are handy for this imo.

Not enough info on what's being used where to throw a decent opinion... consider an inverter.

Re: Low Voltage House Wiring
 

Even if you have a short run and you've calculated an acceptable voltage drop over the run of the wire, you still need to size the wire to your circuit protection. If you run wire smaller than whats required for your circuit protection you risk starting fires. Size your wire to your circuit protection and size your circuit protection to your service requirements.

Re: Low Voltage House Wiring
 

I wonder if anyone has looked into using Power over Ethernet. This gives you up to 16W per connection over regular Ethernet cabling.

Re: Low Voltage House Wiring
 

I have a small cabin that is miles off grid at a hunting location...

i run it totally on 12v and or 110v...here are some thoughts on 12v wiring

#1 you can find a lot of RV type 12v appliances to use i just bought a wrecked RV and salvaged the appliances from it for my cabin

#2 usually a small cabin your wire runs are simple and not long enough to have to go up to a major wire size

#3 with some planning you can put your major amp draws close to the source of the 12v to minimize long runs

#4 if you need to make a long 12v run to a different section what i do is run one major feeder and then put a small Sub panel to split and feed off of

#5 you must get the right wire size to carry the appropriate amperage draw your expecting on each circut and it needs to be fuzed or breakered appropriately

#6 you can get 12v panels and subpanels at RV and Boat salvage places reasonably

#7 some thought should be given to how your going to charge and maintain the 12v battery power source if charging and maintaining is going to be a big hastle it would probably be easyer to generate 110v and wire accordingly

#8 i actually wired my cabin with both 12v and 110v both work but for me it is easyer to use the 110v and use a small inverter suitcase generator and i can power a 12v charger from it to power my 12v appliances etc, so in actual ussage i tend to set up the genny and run it intermitantly to run heavy ussage items and charge the batterys ...then run on 12v all the rest of the time, 110v makes more sense if your trying to run something like a Microwave or AC, if your running a Fridge and lights 12v works ok, a inverter might have been a better route to go except i have several gennys and easy access

a good source for information might be to google "RV 12v Wiring"

just some personal experiences and thoughts i hope what i described makes sense

Re: Low Voltage House Wiring
 

Once again: amp draw dictates wire gauge.

Say it with me now...

If I say it often enough someone will hear it. Breakers/fuses are for when this draw is exceeded.

Re: Low Voltage House Wiring
 

Totally off topic but this discussion reminds me of the time I was making ozone gas using a neon transformer. "It's volts that jolts but it's mills that kills".....I learned a valuable lesson. RESPECT THE ELECTRONS!

Re: Low Voltage House Wiring
 

It may sound like semantics but its not. Amp draw does not dictate wire gauge, circuit protection dictates wire guage, and circuit protection is determined by service requirements.

Re: Low Voltage House Wiring
 

Wire Gauge and Current Limits table + Voltage Drop Calculator

http://www.powerstream.com/Wire_Size.htm

Re: Low Voltage House Wiring
 

Add my voice to the 120V inverter camp. I did an initial costing for 120VAC vs. 12 VDC..

What I found was the higher price of acquiring 12V appliances offset the cost of buying an inverter, higher gauge wire, etc...

When I bug out, all I need to do is take my freezer, bar fridge, dehydrator, TV, laptop, etc.....
I'm too lazy to type out my complete scenario, but I wholeheartedly agree with the "inverter" crowd.

Re: Low Voltage House Wiring
 

May be true in a typical household app, but we are "designing" a low voltage system on this thread where the load will determine the wire gauge, the breakers, and then the service/source itself.

I hope this doesn't distress you... ;)

Re: Low Voltage House Wiring
 

Where did I say that volts dictate wire gauge?

I said if 14 gauge wire is used in a circuit (usually only in lighting circuits) the breaker size cannot exceed 15 amps.

Re: Low Voltage House Wiring
 

My place is still run on 100 year old wiring - yep, a few shorts now and again, but I have an old fashioned fuse box using fuse wire - that blows out well before any risk of fire. You don't need a breaker on a 12v system, just fuses. And pretty much everything is available in 12v circuitry - more expensive, but as said above, a lot of it can be ripped out of RVs.
My fridge came from a boat - it will run on propane, butane, 12v, 110v or 240v. It takes a while to get cold when fired up on propane, so I run it on 240v for an hour then switch to the gas - a man needs a cold beer after cutting wood. Or for breakfast. Or lunch, or any drink in between.