All lights flickering when any load added -- normal, dangerous, or what?

Discussion in 'Electrical Forum discussion & Blog' started by davearonson, Jul 22, 2018.

  1. davearonson

    davearonson Knows Just Enough about Plumbing to be Dangerous

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    Software Development Consultant
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    Virginia
    Ever since we moved into our current house two years ago, we've had a problem in that any time practically any significant electrical appliance starts up (such as the heat pump, dishwasher, usually the dehumidifier, etc., but oddly enough NOT the clothes washer or dryer), all the lights in the house flicker a bit, but especially the living room, which has LED lights. In particular, the lights continue to flicker during most of the cycle of the dishwasher. I think they are at least supposed to be on separate circuits.

    I spoke to an electrical company the home warranty company sent me to, and they said it's perfectly normal for things on the same circuit to make lights dim, and wouldn't listen when I said it was practically ALL the lights in the house, which certainly shouldn't be on the same circuit. So I'm disinclined to trust that, especially since I've gotten, shall we say, rather mixed service out of the warranty company's contractors, but that's another story.

    So, any clues? Anything I can do to fix it, as a homeowner with just a little bit of electrical skills? (I've replaced receptacles and fixtures and such, but do not want to monkey about in the guts of the panel itself. I suspect this needs something like a panel rewiring, upgrade, or some such.) Or are there at leas more precise common bits of jargon I should use to describe this situation to a pro I should call?

    Thanks in advance....
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Flickering usually refers to a fast repeated change. A dimming light would be dimmer while other power was being used.

    I would start by getting a millimeter, and look at voltages at outlets. I would look at voltages in the breaker box with the cover open, but you may not feel confident of your ability.

    Gas dryer?

    There are two hot line coming into the house. About half of the 12o v loads are powered by one hot, and the others by the other hot. The two halfs are often referred to as being on different legs. Adjacent breakers are on different legs.

    Do you know what breaker does what in your house? If not, this is a good time to find out and post a list at the breaker box.

    As to what to know before talking to the electrician, do think about flicker vs dimming. Do check that the symptoms are reproducible vs intermittent. Reproducible will be much easier to troubleshoot.
     
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Retired Systems engineer for defense industry.
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    New England
    A cheaper, analog meter might be more informative than a typical digital one unless it has an instant read bar graph as well as the digital readout. While an analog meter's needle will have some damping to it, if there are variations, they may be easier to spot than with a digital one. While most people don't own an oscilloscope, that would also potentially show what the problem is, especially if it has a storage capability.

    If you understand and feel comfortable doing it, remove the cover of the circuit breaker panel and check the voltage on the main inlet. I'd also verify that the screw clamps are tight and those to the bus bars. Do not do this unless you have the proper safety equipment and knowledge...it could kill you. It's also possible that the power company's feed has a problem. If there is any corrosion on the bus bar of the breaker panel, that can cause problems. While not normally an issue on a new panel, as circuit breakers age, if they regularly see high current and potentially lots of on/off cycles, they do wear out.

    FWIW, I have some LED lights, and my dishwasher and central air conditioner do not cause any lights to flicker.
     
  5. fullysprinklered

    fullysprinklered In the Trades

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    Might be a loose connection on the neutral for the d/w. If not there, start opening boxes and checking all your wirenut connections. Possibly near where the home run enters the affected circuit.
     
  6. Reach4

    Reach4 Well-Known Member

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    Location:
    IL
    davearonson, do any of the lights get brighter during the flickering?
     
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Joined:
    Sep 2, 2004
    Occupation:
    Retired Systems engineer for defense industry.
    Location:
    New England
    A bad neutral connection, depending on where it is, could cause 240vac to appear where it shouldn't. If you had that, you'd probably burn out various things as many items designed for 120vac can't handle 240vac. Some can, but by no means all.

    LED bulbs tend to not like excess voltage and will burn out. An incandescent, might handle a very short spike, but would definitely get brighter and quickly burn out if it saw excess voltage for more than an instant.

    I'd still look for a problem in the main power feed or panel since, assuming we're hearing you right, this happens everywhere in the house. If it were only on a single circuit, it would point towards a problem there. I suppose you could have multiple problems in multiple places, but that's much less likely than where they are all sourced.

    For chance, is your main power drop aluminum? If that's not installed with the anticorrosion paste and torqued properly and the panel is designed to either copper or aluminum, that may be your problem. I'd first eliminate the possibility of any loose or corroded connections inside of the panel. Note, it could be to the meter, either on the inlet or outlet to the panel as well.
     
  8. WorthFlorida

    WorthFlorida The wife is still training me.

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    Orlando, Florida
    I had a similar problem when I purchased my home in 2011. Usually, but not always, when the AC unit turned on the lights would slightly dim for a moment. I know it gets annoying after a while. In a few months time at the main breaker panel I switched off/on the main breaker a few times to perhaps to clean the contacts. I opened the panel just to inspect it and cycled all of circuit breakers. I couldn't tell for sure if it took care of the problem since it was intermittent and at that time we were at the home about every other weekend. After a while I noticed the dimming stopped. I do not know what I did fixed it or something in the neighborhood the power company fixed.

    I would first start with jadnashua recommends inspection the breaker panel for corrosion. Do check the ground rod. It is outside usually near the meter. It may be buried under debris and it has corroded causing a bad or no ground condition.

    Here is a link [https://terrylove.com/forums/index.php?threads/dim-lights-and-low-voltage.73750/] to a problem where voltage would drop drastically. It was a bad connection at the mast that was recently replaced along with a new meter. You may ask the power company out to inspect your connection to the meter and ask that they inspect the blade connections in the meter box. Was the meter changed recently for a new digital wireless type? Some old meter blades and new meter didn't fit well and caused problems including fires.

    Pictures showing how bad corrsion can get in electrical panels.
    https://www.google.com/search?q=oxi...ome..69i57.19811j0j8&sourceid=chrome&ie=UTF-8
     
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