Interesting Home Wiring Problem

Discussion in 'General Electronics Chat' started by random24, Jul 17, 2005.

  1. random24

    Thread Starter New Member

    Jul 17, 2005
    Hello, I'm new to this forum and I thought I'd share a strange problem I encountered today and see if anyone had any ideas about what might be causing it.

    I was helping a friend of mine check some wiring in his house and we noticed an interesting phenomenon. As soon as we put a load on one of the circuits in the house the voltage on that phase would drop to about 75 volts. The other phase however would jump to 200 volts! We checked all the wiring and didn't find any problems. We then went back to the main panel and pulled out all the breakers except one. The problem still persisted! We have determined that his meter is probably bad and he is going to call to get it replaced tomorrow. What I'm curoius about is what exactly is happening in the meter to cause the voltage shift between the phases? After we determined that the meter was probably at fault, my friend mentioned that his neighbor did tell him that there had been a lot of ice on the meter this winter. My friend has been away from his house for about a year and had only periodically checked it. So if there was ice, there was probably water in the meter. I know that this would probably cause corosion but how exactly would that cause the issue we are seeing?

    Thanks for any insight you might have into this weird issue.
  2. pebe

    AAC Fanatic!

    Oct 11, 2004
    I assume your supply is two phases 180degrees apart. If so, the most probable fault is that the neutral wire has a bad connection somewhere.

    The result would be its voltage would be 'pulled' towards the phase voltage whenever a load is applied. That would increase the apparent voltage of the other phase.

    Try checking the voltages where the supply enters the house. That way you can prove if your problem is with the supply or your house wiring.
  3. thingmaker3

    Retired Moderator

    May 16, 2005
    Pebe is quite correct. Poor conduction through the neutral would cause exactly the symptoms you describe. If it were my house, I would be checking for loose or corroded connection on the neutral.