Burnt neutral

Discussion in 'General Electronics Chat' started by Rev Reed, Oct 14, 2014.

  1. Rev Reed

    Thread Starter New Member

    Oct 14, 2014
    3
    0
    Why is it that on 120v wall receptacles that the neutral seams to be the one side that always burns first? Current flow should be equal.
     
  2. #12

    Expert

    Nov 30, 2010
    16,261
    6,768
    No reason, just policy. :D

    Really, the current is equal. You simply stumbled on to a batch of connectors that went bad on the ground side.
    I promise, they burn on the hot side, too.
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    Turn off the appliance before plugging it in...
     
    BR-549 likes this.
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,515
    2,369
    If anything you would think it the opposite as the neutral pin is the larger of the two?
    Max.
     
  5. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
    150
    On what do you base your assumption the neutral 'seams' to always burn first?

    P.S. "Seams" is for sewing.

    And the current flow in the neutral and the 'other side' aren't necessarily equal because the third side - the safety ground - can also carry current during a fault.
     
  6. Rev Reed

    Thread Starter New Member

    Oct 14, 2014
    3
    0
    Good point. Let me rephrase, the left wider one with no shorts to ground occurring.
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,515
    2,369
    If there were any ground current flowing on an appliance plugged into a socket, the current in the neutral could be lower, the degree of current in each would depend on the Earth Ground current in the appliance, but the neutral would not carry any more than normal.
    Max.
     
  8. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    What do you mean by "burns first"? Turn brown, apparently from heat? I don't have any receptacles that "burn" or look burnt. The house is "only" 23 years old, but I don't think a wall outlet should ever burn or discolor unless it is repeatedly overloaded so that it gets darn hot.
     
  9. Johann

    Senior Member

    Nov 27, 2006
    190
    30
    Could be that the wiring system is one where the neutral loops from one socket to the other(s). In this case, there might be a loose connection at such a point where more than one wire is connected to a common neutral connecting terminal of the socket(s).
     
  10. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
    150
    Not sure that rephrase clarified anything for me.

    Repeat: "On what do you base your assumption the neutral 'seams' to always burn first?"
     
  11. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,677
    899
    When you say "burn" do you mean the plastic melts or do you mean the neutral prong gets blackened, like with smoke? Can you wipe it off? I will assume it is the latter.

    In welding, smut forms on the piece being welded more than on the working electrode. One of the contributors to that is thought to be the temperature differential. The electrode being hotter than metal surrounding the weld promotes whatever is oxidized to make smut to condense on the colder surface..

    This may be crazy, but maybe the larger bulk of the neutral means it stays colder than the smaller hot prong. And after many insertions with arcing to either electrode, the neutral may accumulate noticeably more smut on it.

    Just a swag.

    John
     
  12. Rev Reed

    Thread Starter New Member

    Oct 14, 2014
    3
    0
    Best answer yet. Still though, many times it is really burnt, more than just soot.
     
  13. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    Ahh, so we are not talking about the receptacle at all, but rather the prongs on the plug?
     
  14. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,677
    899
    I assume the house has 220V service. Wall receptacles can be on either pole of that supply. Can you check whether the neutral is the burnt prong, regardless of which pole it is one?

    Put another way, I have an older house in which about half of the receptacles are on one pole. It is not unusual to lose power to just half of the 110V outlets. I have not noticed the burning issue you describe with any receptacle, probably because I always turn an appliance off before plugging it in.

    Finally, I agree with MikeML's suggestion. I rarely plug in an appliance that is turned on. In fact, I do that only when the "on" state can't be determined. Consider that when you insert the plug, there will be multiple connects/disconnects until the final state is attained. Those on/off's in quick succession can't be good for anything.

    John
     
  15. ramancini8

    Member

    Jul 18, 2012
    442
    118
    The only time I have seen a burnt contact on a 120V receptacle is when the screw was not tight enough.
     
    Johann likes this.
  16. studiot

    AAC Fanatic!

    Nov 9, 2007
    5,005
    513
    Are you sure the ground to the centre point of your house supply transfomer is in good condition?
     
Loading...