Wiring diagram for conecting Home UPS to home electrical wiring

Discussion in 'General Electronics Chat' started by kanoji_cb, Jul 29, 2011.

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  1. kanoji_cb

    Thread Starter New Member

    Jul 25, 2011
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    :D I am a new member to this Forum. I have a 800 VA online UPS working on 12 volt Battery. When the UPS is connected to 230 v AC power suply, a 12v battery is charged and at the same time stabilized 230v AC output is available which can be used to operate computer, music system and lighting etc. When power supply is failed, the built in Inverter will generate 230v / 50Hz AC by using 12v battery and automaticaly takes the load connected to the UPS instantly. Now I wish to install the UPS to one circuit of home electrical load. Please help me by providing the wiring diagram for the same.
    Thank you in advance.
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    Just curious, have you considered the amperage you will be pulling from that 12V battery? Almost 70 amps. You won't need a battery, you will need a bank of batteries. You would be better off with a generator IMO.
     
  3. kanoji_cb

    Thread Starter New Member

    Jul 25, 2011
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    I am residing in India and in our country power supply is 220v - 240v range. There are many manufacturers are vending 800va UPS systems with a single battery of 12v for home use and they are working fine. The typical load connected to such UPS include P.C., Lighting, Fan, T.V., etc. Now, simply I wanted the wiring diagram - how to connect such UPS FOR HOME USE with the features like the battery should be in charging mode while power supply is present and the normal power supply should be routed through the UPS and on failure of the power supply, the A.C. voltage generated by the UPS by using 12v D.C. (UPS includes Battery charger, Inverter, frequency controller and switching circuit) switching is very fast and the P.C. is not resarted on power failure and changeover.
     
  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    It is easy to use the UPS when it is directly powering/supporting the equipment attached to its plugs. the UPS does the automatic change over and the user sees an UNINTERRUPTED POWER SUPPLY.

    IF you connect the output to an AC circuit in your house, when the AC power grid fails the UPS will try to power up the entire electrical grid in your town or city.

    YOU MUST DISCONNECT THE AC INPUT FROM OUTSIDE TO THE HOUSE. Your house must be isolated from the AC grid. THEN you can use the UPS to power a section of your houses AC wiring.
     
  5. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    You need a fairly expensive device called a Grid Tie Inverter not a UPS.
     
  6. kanoji_cb

    Thread Starter New Member

    Jul 25, 2011
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    Thanks for the reply.
    As I have already said, it is possible to use 800va UPS with a single battery of 12v / 120 AH to handle the home electrical load with automatic changeover and keeping the electric circuit outside the house disconnected, if wired properly. Many people in India are sucessfully using such UPS at their homes. If I purchase such UPS from a local dealer, he will arrange for the wiring to be carriedover at my home. But I am already have a good one in my possession, just simply I wanted a wiring dagram as I have requested in my original thread.
     
  7. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    In the USA, UPS systems for home use are usually small and used only for powering one or two items that have low power consumption i.e., a personal computer. In that case, the UPS is plugged into the mains electrical supply and the item to be powered by the UPS is plugged into the UPS.\

    You state that your UPS system is 800 VA, does it look anything like this? http://www.apc.com/resource/include/techspec_index.cfm?base_sku=br800i If so, simply plug the UPS into mains power and plug your PC, fan, TV, etc. into the receptacles on the UPS. If your UPS is different from this, post a picture of it and you may get better answers.
     
  8. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    You need to give us more details about the UPS model, the electric grid and electric panels at your home.

    I drawed a general diagram (attached), but before starting your project give more information, in order to make it right.
     
    • UPS.JPG
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  9. SgtWookie

    Expert

    Jul 17, 2007
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    With an 800VA inverter connected to a 120AH battery, an estimated efficiency of 85%, loaded to capacity (800 Watts) your battery will be completely dead in just over 1 hour 31 minutes, and your battery would need to be replaced VERY frequently.

    If you wanted your battery to last its' expected lifetime, then you would not operate it with an 800 Watt load for more than 18 minutes.

    It is not a good idea to wire a UPS into a home's wiring, as they are not capable of supplying much power for very long.

    If you had a 100W fan and two 25 Watt energy efficient lamps as the only load for your UPS, and they were running when your electricity went off, you could continue operation for:
    H:MM Battery
    8:09 100% discharged (not recommended; battery will only last a few cycles)
    4:04 50% discharged (Battery life reduced to 1/3 of expected)
    2:26 30% discharged (~80% expected battery life)
    1:37 20% discharged (Full battery life)
     
  10. kanoji_cb

    Thread Starter New Member

    Jul 25, 2011
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    Thanks for the elaborated reply.
    Now, I have developped an idea and drawn the existing and modified wiring diagram as shown hereunder. Will it be ok. Pease help. UPS WIRING FOR HOME.jpg
     
  11. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Is there an AC outlet BEFORE the individual existing circuit breaker? I think it should be after the circuit breaker, right? What's the optional S1 for?

    As Wookie explained, 400W is a lot for this tiny UPS. I don't know how common power outages are in your region, but if you don't want to change your battery every few weeks, keep the power consumption of this load as low as possible.
     
  12. kanoji_cb

    Thread Starter New Member

    Jul 25, 2011
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    Thanks for the reply
    As of now there is no AC outlet before indvidual circuit breaker. It is in the modifiied wiring layout to keep the online UPS in continuously on position and to avoid connection of UPS output to entire town/city. S-1 (OPTIONAL) is a provision made to switch off the system whenever going out for a long period. AC outlet after S-2 (indivdual circuit breaker) is not shown in the diagram, because output is directly connected to consealed wiring for 400W (One P.C. and few CFL lamps)
    Thank you
     
  13. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Well, I don't understand how one could do this if not on purpose.

    In my home I have a main circuit breaker and several smaller circuit breakers for individual circuits. If I take the output of one of those individual CBs , disconnect it, pass it to the UPS and connect the wires that were connected to the CB and connect them to the UPS's output there is no way I could feed the output of the UPS back to mains...

    (People feed back the output of an UPS to mains via a variable power transformer to simulate a load and test the UPS)
     
  14. kanoji_cb

    Thread Starter New Member

    Jul 25, 2011
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    Ok.
    I will explain how my wiring layout is misunderstood.

    In your home you have a main circuit breaker and several smaller circuit breakers for individual circuits. You take the input (not output) of one of those individual CBs, disconnect it, pass it to the AC outlet via S-1 as shown in my modified wiring diagram, now there is no input connection to the smaller CB, connect the UPS to the AC outlet now established and connect the wires of the UPS's output to the input point of the smaller CB, which is controlling meager load of less than 400W. This is to manage with shorter period of main power interruption with minimum load. Whenever main power supply is failed, one circuit in your home is energised by this tiny UPS.
     
  15. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    It's not being misunderstood ;) Thing is, if you put your UPS before the individual CB you have to turn off the main CB as well in order to install the UPS or to do some maintenance on it.
     
  16. SgtWookie

    Expert

    Jul 17, 2007
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    Do not connect the UPS before "one of the smaller circuit breakers".

    If you do that, your wiring to/from the UPS and the UPS itself would only be "protected" by the main circuit breaker, which may be rated for anywhere between 50 and 200 Amperes.

    It is unlikely that the main breaker would trip fast enough to protect your UPS and wiring that you placed between the main breaker and the smaller breaker.

    You really should hire an electrician who is licensed to work on residential units in your area, as very few on this Board are licensed electricians (I am not), and I don't know of anyone on here who is a licensed electrician in India.

    The price of hiring an electrician will be far less than the cost of a funeral.
     
  17. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    I agree to that, but if it works in India as it works in Brazil, everyone would call himself an electrician even if he wasn't. Things run different in these countries.

    Have a look at the attached picture and you know what I mean... not that I encourage it...

    [​IMG]
     
  18. SgtWookie

    Expert

    Jul 17, 2007
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    On this forum, there is one concern that overrides everything else: safety.

    I am not a licensed electrician, anywhere. So, I am not qualified to tell people how to perform modifications on their house wiring, even in my own city.

    Although I am reasonably familiar with such things, I would probably not be able to pass a test to become a licensed electrician. I have no idea what the standards are in India; all I've heard is that the AC they get in households is supposed to be single phase 220VAC 50Hz, but actual line voltage varies greatly. Beyond that, I don't even know what is a typical ampere trip rating for their circuit breakers.

    Most consumer UPSes are designed as a plug-in appliance, NOT as something to be permanently wired in to a residence. I have no reason to believe that our OP's UPS is anything more than a plug-in appliance UPS; so would not be safe to try to wire it as if it were.
     
  19. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Yeah, it was a uncommon idea from the very beginning. Especially he shouldn't OPEN his UPS to do some rewiring. I don't understand why the OP insists in wiring it before the individual circuit breaker...:confused: Doesn't make sense to me.

    And until now I don't know what model it is.
     
  20. monster_catfish

    Active Member

    Mar 17, 2011
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    My understanding is that the OP seeks a storage-battery charging system that will automatically top up one or preferably more deep-cycle batteries during the times when the mains electrical power does flow, but with integral inverter circuitry that will convert the 12 or 24 volt DC output from those intermittently charged batteries into 220 volt AC ( single phase ? ) emergency power which would be used for limited numbers of household appliances when the mains electrical power is off. That 220 VAC emergency power outlet would NOT be connected to the mains wiring at any point.

    Mains power in India reportedly shuts off randomly for hours or days on end, and these battery and inverter systems are in such wide use that I would have thought off-the-shelf systems that fit the bill would be available on the local market there.
     
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