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Thread: Lights flicker when washer is cycling

  1. #1
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    Lights flicker when washer is cycling

    Had a service call 6 months ago where lights would flicker when washer would go thru cycles. Checked all the usual plugs, meter, had power company check there end and tighned all wires in panel. Condos have Al. Wiring. After servicing panel everything was fine until yesterday, same thing is happening. Checked everything again and all is tight and looks good. When washer is on one leg drops to 109v and other raises to 139v. Checked neutral and all appears fine. Maybe the main breaker? Any thoughts would be greatly appreciated

  2. #2
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    Quote Originally Posted by 1haz View Post
    Had a service call 6 months ago where lights would flicker when washer would go thru cycles. Checked all the usual plugs, meter, had power company check there end and tighned all wires in panel. Condos have Al. Wiring. After servicing panel everything was fine until yesterday, same thing is happening. Checked everything again and all is tight and looks good. When washer is on one leg drops to 109v and other raises to 139v. Checked neutral and all appears fine. Maybe the main breaker? Any thoughts would be greatly appreciated
    There is definitely resistance in neutral path contributing to this. Forget the main breaker - even if it has problems is not causing this voltage to neutral imbalance.

    Problem can be anywhere between your panel and the source.

  3. #3
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    Quote Originally Posted by kwired View Post
    There is definitely resistance in neutral path contributing to this. Forget the main breaker - even if it has problems is not causing this voltage to neutral imbalance.

    Problem can be anywhere between your panel and the source.
    *2.

    Hurry up. Don’t dilly dally. Todays electronics often accept pretty wide swings in applied voltage but there is a limit. You should be headed back out the door to the job site now. You can review other posts when you get back.
    Tom
    TBLO

  4. #4
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    1haz:

    You have a neutral problem as you have been told.

    Get a 1500 W space heater to use as a test load. Even a 250 W incandescent might be adequate. With your 15 V change from the washer I could probably find the source of the problem with a 100 W bulb and a fluke 27.

    Go to the main panel. Put your meter probes directly on the incoming neutral wire and one hot wire. I really mean directly on the wires, and not on the terminations. Cycle the 1500 W heater on and off at any convenient outlet. At my main panel this approximate 10 A change produces an 0.4 V change. This was on the non-loaded phase, and on the loaded side it was 0.7 V. In your case it clearly seems to be a neutral problem, and thus the change to either phase will be nearly the same.

    If you see less than 1 V change, then it is not a power company, and/or meter problem.

    For tests where the change was less than 1 V or small do the following:

    Keep the neutral probe were it was, and move your hot test lead to the neutral buss, and while cycling 10 A on and off, check voltage between actual incoming neutral wire and the neutral bus bar. This should be way below a 1 V change, not a lot of millivolts. If the voltage change is substantial, then you know where at least part of the problem is.

    Depending upon what you see probe other places still keeping your reference point the incoming neutral wire.

    For tests where the change was greater than 1 V, then you need to do others tests at various points. Provide us more data.

    .

  5. #5
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    From a utility standpoint....do all of the lights in the house flicker, or just on the washer circuit? Is the voltage change measured at the main panel or somewhere else? We would send a tech (me) out with a "Beast of Burden" to load the service wires with up to 80A on each line leg to neutral. If the voltage dropped significantly on the hot leg but did not rise on the opposite leg, it could be a service line connector or transformer connection problem or even a meter socket problem. If one leg drops and the opposite leg rises, it's a neutral problem, probably a bad connection at the transformer or (if overhead) the weatherhead. Wiring behind the meter is where we could check and an electrician should not. Cut seals are frowned upon. I doubt the utility would be willing to go beyond the service disconnect, though. If the Beast test showed nothing, they might be willing to install a power recorder. Small utilities tend to be much more cooperative than the "big boys".
    Last edited by meternerd; 01-14-18 at 07:56 PM.

  6. #6
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    Quote Originally Posted by meternerd View Post
    From a utility standpoint....do all of the lights in the house flicker, or just on the washer circuit? Is the voltage change measured at the main panel or somewhere else? We would send a tech (me) out with a "Beast of Burden" to load the service wires with up to 80A on each line leg to neutral. If the voltage dropped significantly on the hot leg but did not rise on the opposite leg, it could be a service line connector or transformer connection problem or even a meter socket problem. If one leg drops and the opposite leg rises, it's a neutral problem, probably a bad connection at the transformer or (if overhead) the weatherhead. Wiring behind the meter is where we could check and an electrician should not. Cut seals are frowned upon. I doubt the utility would be willing to go beyond the service disconnect, though. If the Beast test showed nothing, they might be willing to install a power recorder. Small utilities tend to be much more cooperative than the "big boys".
    One should place heavy load on service equipment and check for things meternerd mentioned before even calling POCO. If you don't have any problems at service equipment then you need to go further "downstream" to find where you have a problem. Heavy loading is still a method of making failures occur when testing.

    At branch circuit level a hair dryer, or other similar wattage load is a great testing load.

  7. #7
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    Quote Originally Posted by 1haz View Post
    Checked everything again and all is tight and looks good. When washer is on one leg drops to 109v and other raises to 139v.
    You have a bad neutral somewhere. Where did you measure these voltages at. If you measured at the feeds to the panel then the service neutral is bad.

    If possible it's better to be there when the power company comes to check out the problem.
    The 95% of people that you can't trust give the other 5% a bad name.

  8. #8
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    Quote Originally Posted by meternerd View Post
    From a utility standpoint....do all of the lights in the house flicker, or just on the washer circuit? Is the voltage change measured at the main panel or somewhere else? We would send a tech (me) out with a "Beast of Burden" to load the service wires with up to 80A on each line leg to neutral. If the voltage dropped significantly on the hot leg but did not rise on the opposite leg, it could be a service line connector or transformer connection problem or even a meter socket problem.

    I have had two bad neutrals in the past year where they didn't even bother with the "beast". When I explained the problem they just did a good visual of the neutral cable and found it either frayed or open. We have lots of squirrels in this area and that seems to be the problem.
    The 95% of people that you can't trust give the other 5% a bad name.

  9. #9
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    Quote Originally Posted by growler View Post
    If possible it's better to be there when the power company comes to check out the problem.
    Agreed. A few years ago, I had a customer who had a couple of small fires due to a bad aluminum underground-feeder conductor. The power company guys came out after I left with the main breaker off. They checked the voltages without turning it back on, said everything was fine and I was wrong, and left.

    It took two calls to an engineer to get them to agree that they had to test with the main on to get them to come back and do so. Then they agreed that I was correct about the cause. They found the white dust of aluminum oxide in place of solid aluminum conductor in a 2-foot length of feeder, if memory serves.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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