Lost my electronic equipment to a floating/Loose neutral

Discussion in 'General Electronics Chat' started by andersonmilltexas, Mar 31, 2013.

  1. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    Could someone explain to me how losing neutral would cause the following destruction????????

    Yesterday, I heard a lound pop and saw heavy smoke coming from my dishwasher. Of course I blame the manufacturer and then thought nothing of it.

    The next day My router wall wart melted. Now I becoming concerned.

    Today My DVD player caught on fire and moments later my Printer started spewing smoke.

    I ran to the breaker box and on the way my Microwave poofed and light bulbs were blowing out.

    I had an electrician come over and he said my neutral bus bar at my sub panel vibrated loose. Causing a floating neutral.

    Could someone explain to me how losing neutral would cause this destruction????????
    :(
     
  2. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
    5,003
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    What country do you live in and do you have a 3 phase supply?
     
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  3. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    I live in the United States. I get electricity from the utility company. It is dead-on 60Hz and 120 volts.

    Thank you for helping
     
  4. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    single phase modern wiring , utility and house electricity system.
     
  5. tubeguy

    Well-Known Member

    Nov 3, 2012
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    If the neutral bar is loose at the sub panel, then the hot leg with more load on it at the moment would pull the neutral bar closer to 120 volts, therefore lowering the voltage on that leg, while unfortunately, raising the voltage on the other leg.
    That's a tough one...
     
    Last edited: Mar 31, 2013
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  6. BillB3857

    Senior Member

    Feb 28, 2009
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    Imagine a 12.6V center tapped transformer. Connect a 6.3v indicator from one side to center and two parallel 6.3v indicator lamps (all lamps the same type). When power is applied, all bulbs will see 6.3v. Now, leave the junction where all three lights tie together connected, but disconnect that junction from the center tap of the transformer. Now the voltage will re-distribute and the lamp without the other in parallel will see 2/3 of the total voltage and the two in parallel will only see 1/3 the total voltage. Due to unbalanced loading between the two hot leads in your house, that is what caused your problem.
     
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  7. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    So,
    It was not the side that lost the neutral that blew all my electronics but the opposite side.
    How many volts are we talking about 170??
    Another unusuall aspect to this is that even after opening several breakers the ceiling lamps came on by themselves.
     
  8. tubeguy

    Well-Known Member

    Nov 3, 2012
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    All of the neutrals attached to the loose ground bar lost their Gnd reference which maintains the neutrals at 120 volts potential between the two legs.

    So depending on what appliances, lights etc were activated on each leg, the voltage balance could vary considerably, and would change as different devices were turned on and breakers turned off. So there is no way to predict the actual voltage on each leg at any given time..
     
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  9. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    Would you suggest i use a AVR (ferro type) for my real expensive stuff like the plasma tv?

    I had the problem fixed but then again this or something similar could happen again. If I went that route would you recommend building or buying surplus such as a Solo?

    Thank you.
     
  10. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
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    Sometimes a picture helps. If you can read a simple schematic, maybe this will help.
    I chose some arbitrary resistor values to represent the loads on your two phases. Yours will be different, but the effect is to put too much voltage on the lightly loaded phase, causing too much power dissipation, which leads to smoke, and sometimes, flames.
     
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  11. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    this open or floating neutral would it affect only loads on the one panel, assuming the neutral is disconnected at that panel?

    Would a using a Voltage regulating transformer used on my expensive equipment prevent damage in the event this happens again?:confused:
     
  12. BillB3857

    Senior Member

    Feb 28, 2009
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    How many panels do you have in your house? If more than one, which one is considered the "MAIN"?
     
  13. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    The main panel only powers the three sub panels. One sub panel for kitchen and living area and second sub panel for bedrooms third panel for outdoor lighting

    The main sub only has the large breakers for the subs 60-60-60 and the main breaker 150.

    The ground from each sub runs direct to the main. Each sub panels neutral runs straight to the main. The 3 neutrals tie to the ground inside the main and go to the pole. A seperate ground (inside the main) runs from the main to the water pipe.
     
  14. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    What would be the best protection at a reasonable cost for my media room electronics. Plasma TV Stereo blue ray and all that. I want to protect from a floating neutral and from erratic frequency (when I am on Generator power).

    I am under the impression that a standard Sola brand ferroresonant transformer would not be happy with frequency variations but would be marginally happy with a floating neutral. I suppose that if the volts dropped to much the ferroresonat would collapse.
    I very much would appreciate suggestions. thank you
     
  15. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    The sola transformers will only provide correction to a certain percentage of input variation. Your best bet is to determine why the neutral failed and correct the cause. You don't by any chance have aluminum wiring?
     
  16. timescope

    Member

    Dec 14, 2011
    298
    44
    Sollatek offer a range of voltage protection devices that are effective.

    Don't give up on your damaged equipment as only the power supplies may need repairs. Over-voltage often results in only a blown fuse and varistor if you are lucky, if not, capacitors and semiconductors may have to be replaced.

    The small transformer that powers the control circuit of the microwave may be the only component damaged.

    Timescope.
     
  17. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
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    Bill- It is copper wiring. The bus bar is not copper. Modern panel maybe an aluminum bus, but doubt it probably steel.

    Timescope- Some of the items still work despite the heavy smoke.

    The dishwasher appears to work. However it did produce flames from the plastic. It was billowing smoke. It is an electronic Bosch.

    The microwave we just tossed in the trash.

    The Laser wireless printer lights up but does not print.

    The Blu ray player put out some loud pops and some serious smoke but works. However, it does shut off every once in awhile for no reason.

    The overhead halogens and LED lights popped and are trash.

    The GFCI's melted.

    The Bosch oven occasionally will show F1 code and starts to automatically recycle.

    There was some other large bangs and pops but I have yet to figure out what. Some made the walls shake.

    I do not want this to ever happen again. This is a big financial loss.
     
  18. poopscoop

    Member

    Dec 12, 2012
    139
    16
    Do you live in an earthquake prone area?

    Generally speaking houses do not vibrate, and your problem most likely stemmed from a loose connection. You could spend hundreds of dollars on transformers and voltage regulators, or just take a look at the connection every few weeks. Hell, ask the electrician to throw in an extra neutral connection, the bars usually have several slots. Just don't try to do it yourself, and don't test the neutral connection by hand.

    You could also try making some kind of canary circuit that will sound an alarm if the voltage on one leg ever creeps too high. From your description everything didn't explode at once, so it may buy you enough time to throw the breaker and figure out what's happening.
     
  19. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
    23
    0
    I am in Massachusetts.

    It just occured to me that this surge went through my sub woofer. This would account for the wall vibration. It is a self amp unit. :(
     
  20. andersonmilltexas

    Thread Starter New Member

    Mar 17, 2013
    23
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    I may not be home to hear the canary.

    is there some kind of cut off device. Volts to high or to low cuts out the power to the media room and appliances? I went to the sollatec website but there products appear to be made for non american power systems.
     
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