Ground Neutral Question

Discussion in 'General Electronics Chat' started by les_garten, Oct 3, 2013.

  1. les_garten

    Thread Starter New Member

    Oct 3, 2013
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    Moderator Edit: This was split from here: http://forum.allaboutcircuits.com/showthread.php?t=14393

    I bought a Lutron wireless switch to control a ceiling fan.

    I need to cover up the switch with a painting and wanted to put in wireless since the switch would be inaccessible. So the wireless switch requires a Neutral since I suppose it needs a little power to run the radio and maybe trip a relay.

    My original switch does not have a neutral. It's just a dumb switch that switches the hot wire and has a ground.

    What would be the real life ramifications of using the ground as the neutral.
     
    Last edited by a moderator: Oct 3, 2013
  2. MaxHeadRoom

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    Jul 18, 2013
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    It is not allowed under the electrical code in most countries.
    Ground should never be used as a circuit conductor.
    Max.
     
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  3. MrChips

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    Oct 2, 2009
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    Ground is a safety ground. No current should flow through the ground wire.

    AC Mains Neutral is the proper return path.
     
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  4. les_garten

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    Oct 3, 2013
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    I understand about code, etc. I am wondering about what would/could happen
     
  5. #12

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    Nov 30, 2010
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    If you do not have a neutral wire available in the switch box and use ground as the return current path, some millivolts of AC voltage will appear at the connection to the ground wire in the switch box.

    Not lethal, but strictly illegal.
     
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  6. les_garten

    Thread Starter New Member

    Oct 3, 2013
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    Could you touch a ground wire and get a little buzz maybe?

    I've been around mobile homes that had metal stair rails that you could get a buzz walking up into the trailer.

    Thanx by the way!
     
  7. #12

    Expert

    Nov 30, 2010
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    Depends on your tolerance.:D

    But really, a few dozen millivolts is usually undetectable by humans. That is a good reason why amateurs make this mistake so often.
     
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  8. MaxHeadRoom

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    There a couple of unsafe scenarios that could happen.
    The ground conductor on its way back to the panel is probably grounding other objects and fixtures which are exposed to human contact.
    If you were to use the GND wire as a neutral and it happened to open accidentally or intentionally, this would make any metallic object it was connected to between your connection and the break become live.
    Also if it were opened by someone unsuspectingly in carrying out wiring, full voltage could exist at the point of the disconnection.
    Max.
     
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  9. WBahn

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    Mar 31, 2012
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    Power distribution in the U.S. is predominantly 3-phase. Residential split-phase is derived from one of the phases for any particular residence. As noted elsewhere, the assignment of residences and other utility loads is spread across the three phases to achieve approximate balance.
     
  10. MaxHeadRoom

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    No real difference from any other part of the world, the predominant feature is that rather than use the phase to neutral direct, N.A. uses a local single phase transformer to obtain a 240v centre tapped supply with the centre tap creating a earthed neutral.
    Max.
     
  11. les_garten

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    Oct 3, 2013
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    Yes I see, that makes sense.
     
  12. studiot

    AAC Fanatic!

    Nov 9, 2007
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    We have members in remote areas of both Canada and Australia that have pointed out the use of single conductor (Phase only) AC supply with the local return terminal connected to local ground.

    This does work and saves considerable wiring cost. It is most suitable where there are single or few consumers at the ends so that there are not big fluctuations of created by voltage by mass switching on / switching off.

    It is becoming obsolete.
     
  13. MaxHeadRoom

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    Probably an understatement! ;)

    I have known of remote phone line sytems operating this way.
    Max.
     
  14. sheldons

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    Oct 26, 2011
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    that is definitely not allowed to be wired like that here in the uk due to the fact if theres a fault it would make exposed metalwork live and if the earthing isnt quite up to standard there would be a shock hazard....what you need to do is fit it at your ceiling rose where you have an accessible live feed and neutral that way your wall switch isnt disturbed wiring wise and your safety earth remains a safety earth....
     
  15. WBahn

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    Really? I was reading about this system just this afternoon -- guess it started in New Zealand in 1925 or so -- and it said that it was expanding and becoming more common. It cited specifically in the U.S. northwest and prototype networks in Alaska.
     
  16. WBahn

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    Mar 31, 2012
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    The ground is isolated by transformers on both ends. The claim is that the safety record is comparable, if not better, than the traditional approach provided proper maintanence is done and that the lower cost of installation and maintenance encourages proper maintenance compared to traditional approaches. The reliability is said to be noticeably better, too.

    Apparently one of the biggest problems is that lines coming into contact with moderate resistances to ground, such as through a tree, may not be detectable as a fault and arcing in the tree (or whatever) can cause fires in cases where a traditional system would have faulted. But, by the same token, a significant cause of faults and fires traditional systems can be lines coming into contact with each other and that is not a possibility with single line ground return systems.
     
  17. MaxHeadRoom

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    The return path is unpredictable, both ends are connected to a 12,000 Km Dia spherical conductor .;)
    Max.
     
    Last edited: Oct 4, 2013
  18. t06afre

    AAC Fanatic!

    May 11, 2009
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    From this book http://books.google.no/books/about/Grounds_for_Grounding.html?id=1WfPWbSN7pUC&redir_esc=y
     
  19. sheldons

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    Oct 26, 2011
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    Here in the UK the protective Ground wire -be it for lighting or Ring circuits etc-is only used for that purpose for safety.......if you had no earth connection and the metalwork became live due to a fault there would be no protection against somebody getting a shock....could you post a pic/install info on the units you have ?
     
  20. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Hello, sheldons.

    UK practice has developed over the years. What was done in the (distant) past may have been different.

    Here, where I am, we have what is left of the works of electricity pioneer Andrew Crosse, at Fyne Court.

    I hope soon to visit Cragside, near you, to see the works of your pioneer.
     
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