12v code /supplies

[bridge]

We are investigating the procedures for setting up our home  with 12 v dc. Before you write to me and tell me it's easier to use inverters and stick to ac in the home, please read on. We know it's easier, but we are also convinced that with 12 v appliances and lighting our power consumption will be drastically reduced and thus reduce our power supply demand so fewer panels etc. We have already done some experimenting using 12v dc with a submersible pump and are completely satisfied with it's perfomance and power consumption (rated for 8amps for a deep well but we only have it at 45f and it runs between 5 and 6 amps and the water flow rate is 2 gpm)it remains charged with a small solar panel.  We are not big consumers and don't need every electric appliance that others may not live without.What I am having trouble finding out is if normal oulets and light sockets are compatible and acceptable for the code requirements. I know the Canadian and American codes are different but they have alot of similarities too. We want to avoid the cigarette lighter, feel it's unreliable, and want to use a socket that wouldn't accept a normal ac plug but is rated or usable for dc, where does one find these things?  I've read about some people doing a hybrid system. How do they set it up, with cigarette lighters? Is this really the only option? We already have a line on dc rated panels and breakers, wiring is the same but need heavier guage, so now we are down to the internal hardware.We've been told it's expensive to set up for dc, but from the prices we've been getting, it'll be much cheaper than ac and a big array.It may be a simple thing but I can't seem to find a definative answer with out being told I should just use and inverter and go ac.

Thanks for any input as long as you don't tell me I shouldn't go dc.

[kurt]

all the pages i have read online on wiring a house for dc recomend using a standerd 220v-15a house plug for dc wiring.

 like this

that way the dc plugs will not fit in ac outlets and visversa just be sure you do not have any actual 220v-15a outlets or apliances in the house that use the same style plug. 220v into a 12v appliance would not be a good thing.

if you have 12v appliances that draw more than 15a perhaps s 220v-30a plug would work for those.(see pic below) i would not want to put 30a plugs on every appliance in my house though becouse the plugs are allot larger than standerd plugs..

[ToddH]

Yup, Kurt's reply has the style plugs that are generally used for low voltage homes.

My way is not to code, but it works fine for me.

I used grey colored standard ones that I bought at Home Depot. I mounted them sideways & labeled them "12V" so I don't confuse them with the standard 110V ones that my inverter powers.

Also, I used 14 gauge romex vs. the standard 16 gauge on all my wiring. My 12V loads are light, so I did not need 10 gauge romex. Depending on what your loads are you might need the 10 or larger.

And, I had to drill out the holes slightly in the plugs to get the 14 gauge wire to fit. If you use the screws on the side of the socket, no drilling is required.

[juiced]

I never thought of that aspect of this feild. Can a home be converted or built with DC and still conform to code and be insured?

                 

[bridge]

This is what I am talking to the electrical safety authority about. As far as I can tell it is allowed, low voltage is in the code, so we now have to find out the specifics, the technical advisor there is not even familiar with it, but he's willing to research for me and find out what it takes to make it work with the code. So if it does pass code I can't see why insurance should turn you down, but I don't plan to use insurance so it's not an issue. The biggest problem to me seems to be finding the components for the system and people that are not opinionated to help you find stuff, the general assumption  around here is that you can't do 12vdc and why bother, it's been frustrating, but we are still determined. Thanks for all commments, that's what we were hoping for. It's nice to get honest support and information without opinion.

Bridget

[brock]

I hate the idea of running #10 (pain to work with), but if I had to do it again I would use #10.  I ran #12 and the voltage drop is noticeable.  The other option is using #14 and making more "home runs" to avoid multiple loads on the same line.  Out big problem is in the kitchen with the 12v under cabinet lighting.  They pull 8 amps and that is the farthest run from the batteries so as you turn on the second set of 4 you really see the first set dim and the light in the dining room that taps in along the way drops off also.

So just keep in mind the loads and add the larger wire where you might need it, or multiple runs.  I had planned to use much more 12v when we built, but we use less then I had initially thought, but I am still glad we have some.  It is also nice to know it will work even without an inverter.

I also ran an "emergency light" circuit around the house in key areas, like stairs and the back or dark rooms.  It is feed by 12v and is held off or open by a 120v relay.  My dad always jokes that I know if the power goes out because some lights come on    I did add a switch to make the relay think the power went out for testing and a master switch to turn them back off.  After the last outage I wanted to go back to sleep, but the lights we on  

[DERFMOOSE]

 RE DIMN LIGHTS  wouldn't it be feaseble to put a battery in the line to take up some of the slack it would be recharged from the main bank

[tecker]

   I've looked at raceways for some time now and to wire a house for low voltage requires a complete load calculation. Breakers at each connection point (device)and at a distribution panel. With a UL approach to overload protection .The one thing that will put anyone out of power faster is a short  This is real when a bunch of devices are on a runaway supply of 200 or 400 amps . Burning the house down is not an option.

  Fuses fuse blocks and service disconnects are cheap . If you take this Thing that we're doin out of the shop and into a mainstream home ,. ...... Well you know

[12volt dan]

Bridge

 Yes there are 12 volt codes, I've seen the code book. A lot of it has to doo with wire size and safties but the point is there is code. We are doing what your talking about (living on 12 volt) and I've noticed that most things that run on 12volt are more efficent in terms of energy consumption. On the wire size ,what we did was to put the 12volt sevice pannel in the center of the house to minimize the lenth of wire to the rooms. then run heavy cables to the panel. Don't cheap out on wire size, do it once and do it right (heavy wiring) and it's not a problem.

 The insurance companies are a pain when it comes to insuring somthing they don't understand but shop around you will find what you need

 We are presently building a cogeneration setup for winter heat and power and have just drilled our well (100'). Our well pump (submersible) is 12 volt and moves 4 gal a min at 100 watts.

 My point is it can be done on 12v and done well.

 good luck in your endeavors and don't let people get you down

 12 volt rules

 

[brock]

DERFMOOSE, yes.  As a matter of fact I had moved 2 of my Trojan T125's to under the kitchen sink and fused them and put them in parallel with the other wiring.  It helped a lot, but was a pain because of teh watering and once we had kids I didn't feel safe with them there.  But if you could add a matching battery at the far end of the line it would take up the slack and then slowly charge once the load was gone.

[nack]

There are two sets of documentation that you should have in hand for planning and to defend your design, should the inspector take exception to what you are doing.  First is the National Electric Code (NEC), which is published by the National Fire Prevention Association.  The latest NEC is always available from Graybar Electric, if you have trouble finding it locally.  Last time I had to buy one the paperback cost about $35.  The second documentation you will need must be gotten from your local building department, ask for all local (state, county, and city) addendums to the NEC.  These will describe areas in which your locality differ from the NEC - often silly things like how many feet between staples to support horizontal runs of romex.  If you have these documents, and design according to the requirements specified therein, you should be able to get through your inspection with minimal hassle.

[Ungrounded Lightning Rod]

As a matter of fact I had moved 2 of my Trojan T125's to under the kitchen sink and fused them and put them in parallel with the other wiring.

I would never do that.  Even in the absense of kids.

Lead (even traces of it) and food are not a good combination.  Neither are hydrogen gas and cooking appliances.  Sulfuric acid is not nice, either.  And a little accident with a salt shaker during battery maintainence would fill the house with chlorine gas.  Just for starters.  (Imagine dropping a barbercue fork or a frying pan across the battery posts...)

My take:  Run lots of separate, heavy wires from the distribution panel to the outlets/fixtures and be done with it.  Number 10 isn't THAT much more expensive than number 14.  (Yes, it's stiff.  But I'm wiring a dual-120v circuit with it right now, with dual duplex outlets in two-gang boxes which is pretty cramped with such stiff wire.  That's a pain - but doable.  If you're using a separate 10-2 + G run per outlet it's a piece of cake.)

And if the house is REALLY long, put a second battery bank OUTSIDE near the other end, feed it with a heavy bus from the primary system, and use a second subpanel for that end of the house.  Or just use the heavy bus to the subpanel and leave off the battery.

[Ungrounded Lightning Rod]

Also talk it over with your inspectors and ask their advice.  In some cities (like mine) they're happy to help you out with friendly advice, especially if you come to them and ask.  Respect their authority and ask for advice - and if you think they're misinterpreting something, try phrasing it in a "What was I missing when I thought it said X?" mode.

They'll tell you about their enforcement hotbuttons, too.  The REAL code is not just NEMA + local mods.  It's NEMA + local mods + the code department's undocumented additions and interpretations.

(I always work to pass all three, plus my personal overdesign biases.  When the inspectors passed my electrical work on the kitchen remodel they told me they were very impressed and wished the pros would do as well.)

[nack]

Amen, brother!  Never pick a fight with the inspector, right or wrong (s)he can stop you in your tracks.  And it is just human nature that (s)he will like you better for recognizing his/her authority by asking.

[bridge]

I'm so glad to hear about so many doing the same thing we want to to. Where does one find the supplies for doing 12v to code, I am going to have to deal with inspectors, but they seem eager to help at this point. I am just having trouble finding stuff. Do you use square D panels and breakers, what's acceptable, I have some one looking into cutler hammer products, but he's not sure they're rated for dc. Any suggestions?There doesn't seem to be an easy location for all products for 12v. I guess that's what I get for not being a sheep!

[nack]

Again, you might try Graybar - they have a pretty extensive product line.

[ghurd]

I'm big on 12 volts for smaller systems. It may cost a tad more for wire, but everything else is cheaper and eaisier to find locally. Shipping costs for the 24 volt stuff is going to cost more than you save on the wire. The local chain dept. store has 12V things like batterys, inverters, light bulbs, TVs and blenders, etc. for a price comparable to mail order. Some of the big auto parts stores have a lot more stuff than one might think.

We ran 12v with 8 ga THHN (bought the red 250' roll cheaper than 2 100' rolls of 10ga, permanent markered the negative black. I'm the only one messing with it.)the whole way.

We striped 1/2" where needed, and dropped in 14 ga 2 conducter "trailer light plugs", from the top through 1/4" holes, then soldered them in to the 8 ga.

Easy and cheap to add or remove a plug. The 1/4" hole in the floor behind the carpet tack strip, under the carpet, will never be noticed.

Have an adapter, trailer plug to lighter socket, for things that use it.

8ga reduces the V drop. 16" of 14 ga won't count for much. There is no danger of plugging something into the wrong voltage or backwards.

This is a smaller system, 1 battery, 1 panel. Most loads are 1 amp to 4 amps, and not many at once.

I like cheap, easy and change-ablity. It worked for us.

[pdvjak]

Hi;

You might want to look at systems used for yachts... 'Yachties' have literally lived with 12V for decades, in the most challenging environments.... Using wind, solar, what have you.... Mixing drinks, watching TV, using microwaves and washing machines even.... Good place to start is probably West Marine.... I'm sure there is also some USCG or ABS or similar code for DC systems in ships/yachts that might be a good guide, too.... Hope this helps....

[nobicus]

If you were in the UK I would advise a visit to a caravan dealer and go through the accessory sales shop.  I think that they are called RVs in America and Canada.  When we had our caravan we had a shower run from a propane heater that heated about 3 gallons of water on a continuous basis.  The taps were all demand in that the pump switched on as you turned on the tap.  The electricity supply was all 12volt dc.

Best of luck.

[jacquesm]

watch the rating on your breakers ! do not use AC breakers, AC breakers assume that the voltage will cross 0 60 times per second to extinguish the arc. A DC rated breaker of the same amperage is of much heavier construction then an AC breaker, it has multiple breakers in series to help extinguish the arc.

another option, instead of 12V is to use 24 volts, many truck accessories are 24 volts. save a bit on wiring that way if you decide to go DC.