---
+ Post New Thread
Results 1 to 5 of 5
  1. #1
    Member level 3
    Points: 1,234, Level: 7

    Join Date
    Jan 2009
    Posts
    57
    Helped
    4 / 4
    Points
    1,234
    Level
    7

    Neutral to Earth voltage

    Hi,

    Could anyone tell me what has to be voltage b/w Neutral to earth.

    I have the system which when I connect , it shows around 106Volts b/w neutral to earth.

    Line-Neutral Voltage Line-Earth Voltage Neutral-Earth Voltage
    227VAC 120VAC 106VAC

    Thanks in advance

    •   Alt17th January 2011, 07:46

      advertising

        
       

  2. #2
    FvM
    FvM is offline
    Super Moderator
    Points: 172,245, Level: 98
    Awards:
    1st Helpful Member

    Join Date
    Jan 2008
    Location
    Bochum, Germany
    Posts
    27,933
    Helped
    8811 / 8811
    Points
    172,245
    Level
    98

    Re: Neutral to Earth voltage

    Neutral is not guaranteed to have an earth connection. I know, that in some countries with 120 VAC voltage standard, it's common to connect two 120V transformers to generate 230/240V, with center tap earth connection. Or you have an isolated transformer secondary.


    1 members found this post helpful.

    •   Alt17th January 2011, 08:18

      advertising

        
       

  3. #3
    Junior Member level 1
    Points: 985, Level: 7

    Join Date
    Nov 2007
    Posts
    18
    Helped
    3 / 3
    Points
    985
    Level
    7

    Re: Neutral to Earth voltage

    Line - Neutral Voltage = Supply Voltage

    Line - Ground Voltage ~ Supply Voltage (For testing purpose only)

    Neutral - Ground Voltage ~ 0V (Theoretical, but practically it should be around 2 - 6 V)

    Neutral - Ground Voltage value depends upon the quality of Earthing, a lower value is always preferred. If its high which shows there is some problem with earthing, this can result in electricity passage over device cabinet, casing etc which may result in malfunction & can even give shock to the operator.


    1 members found this post helpful.

    •   Alt17th January 2011, 18:10

      advertising

        
       

  4. #4
    Advanced Member level 5
    Points: 18,010, Level: 32

    Join Date
    Dec 2010
    Location
    Southampton and holiday cottage in Wensleydale (UK)
    Posts
    3,544
    Helped
    929 / 929
    Points
    18,010
    Level
    32

    Re: Neutral to Earth voltage

    The neutral conductor carries the return current to the supply transformer. Depending on the current, length and resistance of the Neutral conductor, the neutral to earth voltage can be up to 10V. In America where there is a 115-N -115 supply, any differences between the currents taken by the two 115 V supplies flows down the neutral. There would be no neutral current with 230V loads.
    Frank


    1 members found this post helpful.

  5. #5
    Full Member level 4
    Points: 1,678, Level: 9

    Join Date
    Jan 2011
    Location
    Newcastle, UK
    Posts
    202
    Helped
    77 / 77
    Points
    1,678
    Level
    9

    Re: Neutral to Earth voltage

    To develop FvM's post, it is actually very common for generating sets to use a centre-tapped earth. These may even be used to provide power to installations which are usually supplied from the local supply and this means that their voltages can be unpredictable.
    With a centre-tapped earth, the neutral - earth voltage is the same as the live - earth voltage. (and both of these are half the live - neutral voltage).

    In places where this DOES NOT apply, then the neutral - earth voltage should be very low, as others have posted, but there are several reasons why it can vary substantially, particularly when the load on the 3 phases is very unequal. The heavily loaded phases will "pull" the neutral voltage towards them. In fact the voltage distribution across 3-phase supplies can become quite complex and we should never make assumptions about neutral being "safe". It isnt.


    1 members found this post helpful.

+ Post New Thread
Please login