Black Moon LTD
Results 1 to 18 of 18

Thread: Partial power outage..

  1. #1
    Flashaholic*
    Join Date
    Jun 2004
    Location
    Brooklyn NY
    Posts
    3,835

    Default Partial power outage..

    Well, right now, I have a partial power outage. Theres power in select rooms of my house, same thing is happening with my neighbors..so I'm typing by RR 2AAA light right now. Anyone guess what could be the cause?

  2. #2

    Default Re: Partial power outage..

    Weird. Might be a good idea to unplug electronics to protect from a surge...

  3. #3
    Flashaholic FLASHLIGHTMAN's Avatar
    Join Date
    Mar 2002
    Location
    Iowa
    Posts
    106

    Default Re: Partial power outage..

    I would guess that there is a fuse blown at the transformer.

    It sounds like to me that you are only getting 1 leg of the 220 that comes into your house. The reason you have select rooms on right now is that your service panel is split (every other breaker) to one side of the 220 that comes in. It takes both legs to get the 220 volts, but if one leg is down, you would still have 110 on the live side.

    I would only guess this is true since your neighbors are experiencing the same thing. If it had been you only, I would say it was in YOUR main panel.

    Good luck! At least your computer is still up!
    I don't always sit in the dark, but when I do, I'm usually playing with flashlights.

  4. #4
    Flashaholic* Morelite's Avatar
    Join Date
    Nov 2005
    Location
    Central PA
    Posts
    2,238

    Default Re: Partial power outage..

    The transformer has a secondary output line dead.

  5. #5

    Default Re: Partial power outage..

    Quote Originally Posted by FLASHLIGHTMAN
    I would guess that there is a fuse blown at the transformer.

    It sounds like to me that you are only getting 1 leg of the 220 that comes into your house. The reason you have select rooms on right now is that your service panel is split (every other breaker) to one side of the 220 that comes in. It takes both legs to get the 220 volts, but if one leg is down, you would still have 110 on the live side.

    I would only guess this is true since your neighbors are experiencing the same thing. If it had been you only, I would say it was in YOUR main panel.

    Good luck! At least your computer is still up!
    HEY! That's what I was gonna say!

  6. #6
    Flashaholic*
    Join Date
    Oct 2003
    Location
    Two Rivers, Wisconsin
    Posts
    3,828

    Default Re: Partial power outage..

    Luckily for you & your neighbors that the neutral didn't open or you may have zapped some of your equipment.
    I'm absolutely certain that I need another flashlight.

  7. #7
    Flashaholic* Morelite's Avatar
    Join Date
    Nov 2005
    Location
    Central PA
    Posts
    2,238

    Default Re: Partial power outage..

    I would be good to make sure all 220 volt devices like dryers, range, over, well pump, etc is turned off or disconnected. If one of those happens to be "on" it could feed the electricity from the powered leg (side of your panel) to the dead leg and cause a "brownout" effect on the devices connected to the dead side.

  8. #8
    Flashaholic*
    Join Date
    Jun 2004
    Location
    Brooklyn NY
    Posts
    3,835

    Default Re: Partial power outage..

    Thanks! Theres no 220V inside my building, so I'm safe..I think, power is now restored

  9. #9

    Default Re: Partial power outage..

    If this happens again, turn off your power at the main breaker immediately. Then call your electric utility's emergency number and report the outage. Don't turn it back on until they've fixed it. Indeed, you are VERY lucky the neutral didn't open. That can and does cause fires.. and if one leg is out, I wouldn't trust the neutral either. If your power is doing something weird, shut it off and report it - that's the safest thing to do.

    The symptoms of an actual open neutral are some lights dimmer than usual and others BRIGHTER than usual. If you ever see that, turn the power off IMMEDIATELY!

  10. #10
    Flashaholic*
    Join Date
    Jun 2004
    Location
    Brooklyn NY
    Posts
    3,835

    Default Re: Partial power outage..

    Thanks for the warning!

  11. #11
    Flashaholic
    Join Date
    Jun 2005
    Location
    Western Massachusetts, USA
    Posts
    237

    Default Re: Partial power outage..

    My EE professor just told us a story the other day where the neutral line fell out of it's clamp in his breaker box because the electrician didn't tighten it down, and that he ended up testing 3V on one side of the house and 237V on the other side, which of course meant one side of the house didn't work and all the electronics which were connected to the other side burned up because they experienced double their rated voltages.

    Can someone explain what exactly the neutral line does to keep these two 120V lines at their appropreate voltages?

  12. #12
    Flashaholic* yuandrew's Avatar
    Join Date
    Apr 2003
    Location
    Chino Hills, CA
    Posts
    1,273

    Default Re: Partial power outage..

    I had the same thing happen as well in my house shortly a few years after we moved in. Electrician said it was a bad neutral connection inside the breaker panel. Dad later told me the red wire probably shorted to the neutral

    Around 240 volts went to one part of the living room and a very low voltage went to the other part (dim lights in half the house and really bright lights that lasted for a few seconds in the other half). Fried two TVs, a stereo, VHS tape rewinder, my Nintendo, a VCR, Aquarium pump, three fluorescent light ballasts, and popped a few incandescant bulbs.

  13. #13
    Flashaholic* turbodog's Avatar
    Join Date
    Jun 2003
    Location
    Southern USA
    Posts
    4,062

    Default Re: Partial power outage..

    Quote Originally Posted by GarageBoy
    Thanks! Theres no 220V inside my building, so I'm safe..I think, power is now restored
    So...... you don't have a clothes dryer or an oven/stove?
    This is your life, and it's ending one minute at a time.
    Be prepared for the truth.

  14. #14
    *Flashaholic* CLHC's Avatar
    Join Date
    Dec 2004
    Location
    PNW|WA|USA
    Posts
    5,685

    Default Re: Partial power outage..

    At least you're prepared with some light right?
    LUX'Ottica

  15. #15
    Flashaholic*
    Join Date
    Jun 2004
    Location
    Brooklyn NY
    Posts
    3,835

    Default Re: Partial power outage..

    Again..220 inside my building..
    Gas Dryer..Washer/Stove all use 120V

  16. #16
    Flashaholic*
    Join Date
    Jun 2004
    Location
    Brooklyn NY
    Posts
    3,835

    Default Re: Partial power outage..

    Wait, when the neutral blows..doesn't the electricity cease to flow?

  17. #17
    Flashaholic*
    Join Date
    Oct 2005
    Location
    Southern California
    Posts
    728

    Default Re: Partial power outage..

    Not with AC power, it just needs two live wires.

  18. #18

    Default Re: Partial power outage..

    Most residential power in the US is provided as single phase 220V with a center tapped neutral. This means that you can draw 220V between the two hot legs, or 110V from one leg to neutral. So long as the neutral is properly connected, it will keep the voltage on each leg approximately correct. (bextech, the neutral carries the *difference* in current between the two hot legs. If the two legs are each drawing the same amount of current, there is no current carried by the neutral. As soon as they fall out of balance, the neutral carries as much current as is needed to keep the two legs in balance. I can dig out the mathematical explanation if you'd like.)

    Take away the neutral's connection to the power company's transformer, and you don't have anything holding each leg to 120V. The one that needs more power will actually get LESS, and the one that needs less power will actually get MORE. This is a Very Bad Thing. If this happens, 220V appliances will continue to work fine, because they are drawing hot to hot and not using the neutral. (This is what yuandrew described exactly.)

    So why don't we use hot/hot all the time? Because it's more expensive. Center-tapped single phase is a very efficient way to provide 110V service while still having 220V available for heavy loads where the wire size required at 110V would be even more expensive. On ships, for instance, where there is no ground reference to tie neutral to, delta power (hot/hot) is used. That would be two 60V hots together forming a 120V supply, just like the two 110V hots in residential service together form a 220V supply.

    One more complication - you're in NYC. Many older apartment buildings actually use commercial three-phase power. With that setup, you have a neutral and THREE hots that are out of phase with each other. You can develop 110V from any one hot to neutral, or 208V between any two hots. The advantage of this system is that it's much more efficient when all three hots are attached to a large motor. For instance, elevators work much better on three-phase power.

    Note that I am talking about US/Canada power here. It's done differently other places; the UK, for instance, has a particularly unusual approach.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •