(206) 949-5683, Top Rated Plumber, Seattle
Page 1 of 3 123 LastLast
Results 1 to 15 of 32

Thread: voltage drop

  1. #1

    Question voltage drop

    My meter point is right at the ( hot ) conductor before the main breaker. The two hots that come off the meter can and into the house before hitting the main panel.. One meter lead is on the neutral and the other on the hot.. Both show 120 volts.. Then, when I turn the microwave on or any large load from any plug everything dims down and on the one conductor the voltage drops to 95 V and the other conductor swings up to 155 Volts.. Cant figure out what is going on? Please advise? Recently purchased forclosure house with what appears to be new service panel.. Thanks

  2. #2
    DIY Senior Member Reach4's Avatar
    Join Date
    Sep 2013
    Location
    IL
    Posts
    1,273

    Default

    Both hots show 120 volts to neutral and you will measure 240 hot-to-hot.

    Are you saying that only two wires come from the "meter can" into the house? That's a big problem that needs fixing.

    Or are you saying that a third wire comes in. Is that third wire at the same potential as your neutral bar? If so, you probably will need to involve the power company. One of the problem may be in the power company wiring. At least one of the problems is in your local wiring. I think you probably want to call your electrician first, but maybe calling the power company first is better. I don't know.


    You have an additional problem in that your local ground connection is not good enough.

    So probably two problems that need fixing. It may be good that you have two problems because one problem alone might have never been noticed.

  3. #3
    Test, Don't Guess! cacher_chick's Avatar
    Join Date
    Jan 2008
    Location
    Land of Cheese
    Posts
    3,154

    Default

    The connection to neutral is failing. Make sure yours is tight in the main panel, and if so call the power company. Here, the line from the pole to the meter belongs to the p.c.

  4. #4
    Jack of all trades DonL's Avatar
    Join Date
    Mar 2011
    Location
    Houston, TX
    Posts
    3,661

    Default

    You may have a grounding problem at the Pole Pig, HV transformer.

    The neutral can float if the ground is missing.

    That can be a Big problem.


    Good Luck.
    Theory only works perfect in a vacuum.

    Cyber Security Protection for Windows C:\ > WWW.WinForce.Net

  5. #5
    Licensed Electrical Contractor Speedy Petey's Avatar
    Join Date
    Jun 2007
    Location
    NY State, USA
    Posts
    976

    Default

    Quote Originally Posted by DonL View Post
    You may have a grounding problem at the Pole Pig, HV transformer.

    The neutral can float if the ground is missing.

    That can be a Big problem.


    Good Luck.
    This is NOT a grounding problem. It is a neutral problem on the secondary side of the utility transformer.
    Answers based on the 2008 & 2011 NEC. If you're on the '14 already I feel sorry for you.

  6. #6
    Electrician ActionDave's Avatar
    Join Date
    Feb 2009
    Location
    Colorado
    Posts
    328

    Default

    Agree with others, bad neutral. Shut off the main and call the power company.

  7. #7
    Jack of all trades DonL's Avatar
    Join Date
    Mar 2011
    Location
    Houston, TX
    Posts
    3,661

    Default

    Quote Originally Posted by Speedy Petey View Post
    This is NOT a grounding problem. It is a neutral problem on the secondary side of the utility transformer.

    OK.

    This old dog loves to learn new tricks.

    Is the Neutral and Ground NORMALLY not the same at the Transformer ?

    They are around here.

    And the Ground at the Meter Service is a safety, just encase there is a neutral fault. It can keep HV from going into the House. Like when a HV transformer shorts out Primary to secondary.

    I understand that it depends on the system used. Some systems carry neutral, some rely on Earth Ground.

    I do like to be corrected if I am wrong.


    Thank You, I want to learn more.
    Last edited by DonL; 01-23-2014 at 11:27 AM.
    Theory only works perfect in a vacuum.

    Cyber Security Protection for Windows C:\ > WWW.WinForce.Net

  8. #8
    DIY Senior Member Homeownerinburb's Avatar
    Join Date
    Jan 2012
    Location
    Los Angeles, CA USA
    Posts
    505

    Default

    Just to repeat what you have been told:

    This is a bad neutral from the power company. And it ain't no joke.

    Your whole house could get fried. Have the electric company come out yesterday.

  9. #9
    DIY Senior Member Reach4's Avatar
    Join Date
    Sep 2013
    Location
    IL
    Posts
    1,273

    Default

    Quote Originally Posted by Homeownerinburb View Post
    This is a bad neutral from the power company.
    You are presuming that the neutral wire was wired into the breaker panel from the meter box.

    We all agree that quick action is required, but the OP seems to be gone.

  10. #10

    Default

    3 conductors come off the meter can and into the service panel. 2 hots and a neutral. As I said, my DMM reads 118V off each leg with light loads. But, when I plug in larger loads ( microwave or fridge ) the voltage jumps all over the place. I am still looking over this previous owners work ( panel appears to be new - maybe few years old GE goldmark copper conductor bus bars ) Couple observations I can add. I noticed on some romex 12/2 in a crawl space area the wire is chisel damaged a bit, maybe a nick in the neutral. Would a nick in 1 wire cause all this dimming? Also, the meter can and the service panel have separate ground rods that are not connected in a closed loop, but are in contact via the metal conduit pipe that runs from the meter can to the main panel ( through the wall of the house ) I removed the bulb and cleaned and tightened all contacts in the meter can using acetone on a long wood handled small service brush. Please advise? EDIT - Also, forgot to add - I observed a split bolt connector on the neutral leg. I guess the wire was to short and they added 20" of #2 conductor to it. The split bolt connector is very clean and tight and I'm wondering if that could be my issue whereas I vaguely remember people saying this is a no / no. But, if its clean and tight that shouldn't be an issue, correct??? Also, neighbor and I share the same transformer and he says he has no issues with lights flickering or dimming. Problem seems to be mine alone. Thanks Again
    Last edited by Mike Pastorelli; 01-24-2014 at 07:27 AM.

  11. #11
    Jack of all trades DonL's Avatar
    Join Date
    Mar 2011
    Location
    Houston, TX
    Posts
    3,661

    Default

    Quote Originally Posted by Mike Pastorelli View Post
    3 conductors come off the meter can and into the service panel. 2 hots and a neutral. As I said, my DMM reads 118V off each leg with light loads. But, when I plug in larger loads ( microwave or fridge ) the voltage jumps all over the place. I am still looking over this previous owners work ( panel appears to be new - maybe few years old GE goldmark copper conductor bus bars ) Couple observations I can add. I noticed on some romex 12/2 in a crawl space area the wire is chisel damaged a bit, maybe a nick in the neutral. Would a nick in 1 wire cause all this dimming? Also, the meter can and the service panel have separate ground rods that are not connected in a closed loop, but are in contact via the metal conduit pipe that runs from the meter can to the main panel ( through the wall of the house ) I removed the bulb and cleaned and tightened all contacts in the meter can using acetone on a long wood handled small service brush. Please advise

    Where are you measuring the voltage ?

    If you are measuring the voltage at the main breaker, then that would indicate a problem on the service feed.

    You should have the electric company check at the pole or HV transformer.

    They should not charge you for that service.


    Good Luck.
    Theory only works perfect in a vacuum.

    Cyber Security Protection for Windows C:\ > WWW.WinForce.Net

  12. #12
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    Location
    North Carolina
    Posts
    2,523

    Default

    Quote Originally Posted by DonL View Post
    Is the Neutral and Ground NORMALLY not the same at the Transformer ?
    No. There is a big difference between the neutral and ground every where on an electrical system

  13. #13
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    Location
    North Carolina
    Posts
    2,523

    Default

    Quote Originally Posted by Mike Pastorelli View Post
    3 conductors come off the meter can and into the service panel.
    As many has already told you call the power company right now.

  14. #14
    DIY Senior Member Reach4's Avatar
    Join Date
    Sep 2013
    Location
    IL
    Posts
    1,273

    Default

    Quote Originally Posted by jwelectric View Post
    No. There is a big difference between the neutral and ground every where on an electrical system
    Now you are just trolling. You know that is not true.

  15. #15
    Electrical Contractor/Instructor jwelectric's Avatar
    Join Date
    Jun 2007
    Location
    North Carolina
    Posts
    2,523

    Default

    The neutral is the center tap of a transformer but grounding is the connection to earth in an ungrounded system there will be no neutral from the utility but there will always be an earth connection or grounding if one pleases.

    It is very true that the utility connects their earth ground to the neutral just as we do at the service equipment but the neutral is a current carrying conductor and the grounding is not current carrying a very huge difference.

Similar Threads

  1. Voltage drop in underground cable
    By silverfox52009 in forum Electrical Forum discussion & Blog
    Replies: 46
    Last Post: 05-24-2012, 05:55 PM
  2. Flickering lights on circuit with low voltage and line voltage bulbs
    By davidwie in forum Electrical Forum discussion & Blog
    Replies: 5
    Last Post: 04-18-2011, 07:34 AM
  3. voltage drop
    By ugabulldog in forum Pumps and Tanks Well Forum & Blog
    Replies: 7
    Last Post: 01-22-2011, 03:38 PM
  4. Service entrance cable size & voltage drop
    By curtherrin in forum Electrical Forum discussion & Blog
    Replies: 5
    Last Post: 08-24-2009, 12:47 PM
  5. Lights flicker and Voltage Drop Question
    By Pip in forum Electrical Forum discussion & Blog
    Replies: 9
    Last Post: 12-18-2008, 06:25 PM

Bookmarks

Posting Permissions

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