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Shocks/Wacky voltage readings/NO exterior light

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  • Shocks/Wacky voltage readings/NO exterior light

    Posted By: CLamslam Sam

    In my kitchen I have 3 recessed lights, controlled by a 3 way at the entrance to the kitchen and a 3 way at the opposite end of the kitchen by the sink. There is also a simple switch next to the sink 3-way switch that controls an exterior patio light.

    When washing the dishes the other evening a got a good jolt when I tried to switch the kitchen lights on. Of course one hand was touching the metal sink and the other was touching the metal plate that covers the switches. I got my DMM out and verified that there is 120v on the metal switch cover when the switch is in the "OFF" posistion. Also the exterior light only came on if the kitchen lights were off.

    I had gotten shocked before by the switch cover but it was never bad enough to assume it had a full 120vac. It does tho.

    When I looked at the original wiring it was a mess, I dont even know how the lights functioned with the way they were wired.

    So I searched the internet to find a diagram that would fit my application. And found this: http://www.switchandoutletwiringmade...power-fixture/

    This is my exact setup except that the wire going from the fixture to the first switch is a 3-conductor no ground. Also none of the switches have ground terminals because of vintage. My incoming power is the only cable with a ground.

    An addition is the switch for the exterior light and the exterior fixture. I wanted to wire this so that it worked independent of the kitchen lights.

    I wired it all up according to the diagram linked above, of course with the addition of 2 more recessed lights.

    The recessed lights all work properly with the 3-way switches however....

    The exterior light does not come on with any combo of switching.

    You are asking how I wired it. I had an unused "red" from the 3 conductor cable from the fixture so I used that as my neutral, hooking into the first neutral node at the first fixture. I connected the other end of the red neutral to the exterior lights "neutral" wire. Since this ext. switch is located with the first switch I simply connected a black hot jumper from the ext. switch to the incoming "white" hot from the first recessed fixture. Then I connected the ext. fixture's black to the other terminal on the exterior switch. So for the exterior light I am running a neutral to the main neutral and am switching hot. Where did I go wrong?

    I realize that I should have the "white" in my 3 con. cable as my main neutral and the "red" as the incoming hot, for safety reasons. Nevertheless it should work as far as I know. My exterior light circuit is in parallel to the 3-way circuit and I am switching "hot". The bulb wasnt blown 2 days ago, so I am assuming it is a good bulb.


    Another thing I am concerned about is I still read 10-30vac from my switch cover to my sink. It is not shocking anymore but I'd like to see zero voltage here. Thanks for the help.

  • #2
    Posted By: dkerr

    Thanks for your post, I just sent a note to our regulars / moderators and you will get replies soon. This is a new website and new forum and it is taking a bit of time to get ranked up on the search engines, we expect these forums will become quite popular as the new sites gain popularity.

    What you are saying is a bit weird, and I have to site and draw out what you have described and try and make some sense of it. Under US & Canadian codes using a red as a grounded conductor (neutral) is not allowed but that is just a color designation and as you described you just used a different color then is by code so that should not be the cause of the problem. Just have to bear with me. Neutrals can sometimes have a small voltage on them in relation to ground if other items are in use on the same circuit. Is your electrical boxes grounded and is there any chance that the switch screws are rubbing against the metal electrical box?

    Comment


    • #3
      Posted By: suemarkp

      Lots of problems here. First, how old is your house? For quite a while in the code, metal boxes, or any box with a metal face plate MUST be grounded. You could be grandfathered, but it is still a good idea. If you can't easily ground these switch boxes, then at least change to plastic switch covers and nylon screws.

      You should use tape to mark conductors being used differently than their color indicates. Red as a neutral isn't allowed, but if you put white tape on it at least someone will have a clue what you're doing. Likewise, whites being used in a switch loop should have black tape added. Same for the white in the 3 conductor wire if it is a switchleg in the 3-way.

      I'm not sure why your exterior light doesn't work. It sounds like you wired it right (other than stealing a neutral from a different place which is not allowed with ferrous boxes). I wonder if that red wire was broken and that is why it was "available". You'll need to test it.

      I didn't see how you changed the voltage on the switch plate either. I'm thinking someone tightened the cable clamp too much in your switch box and the clamp is cutting into a hot wire, energizing the box. The "correct" solution for that is to ground the box which will cause the breaker to trip. Perhaps just moving the wires around changed how much of the cable was being cut by the clamp.

      If you are using a digital meter and your boxes are ungrounded, you could be reading "phantom voltage" on the box. But phantom voltage won't shock you. This is inductively coupled, but is so weak that a minor load will pull it to 0 volts. If you have an old analog volt meter, try measuring with that. Otherwise, connect a small wattage light bulb between the box and a neutral and see if the filament glows at all. If so, it is phantom voltage.

      Your best solution is to rip out the wires and do things over with proper wire colors, quantities, and grounding wires.

      Mark
      Kent, WA

      Comment


      • #4
        Posted By: CLamslam Sam

        First, how old is your house? For quite a while in the code, metal boxes, or any box with a metal face plate MUST be grounded. You could be grandfathered, but it is still a good idea.
        It was built in 1929. Half the house is rewired and is grounded. Of course the baseboard sockets didn't get reworked with ground.

        It sounds like you wired it right (other than stealing a neutral from a different place which is not allowed with ferrous boxes). I wonder if that red wire was broken and that is why it was "available". You'll need to test it.
        The red was used in the original wiring, which was a mess. From the diagram I used I did not need a 14/3 from fixture to first switch so I used the unused red to take a neutral down to my exterior light switch. Yes, it would have been easy to have the red carry the incoming hot and have the white on neutral, and I will make the switch once I get it working.

        I could at least purchase grounded switches and use the white as a ground and the red as incoming hot. Then run new power for the exterior light. I know probably a code violation, I'm just trying to get it working and not have voltage on ground,(I think your right about the phantom power). I only have a DMM. But will try the light bulb test.

        Comment


        • #5
          Posted By: dkerr

          Considering the age of the home, sometimes things get wired in stages over the years, and you may come across different patterns / types of wiring in the home especially if additions to the home where made over the years. It would be nice for such a home to be completely rewired, but you may not have the budget for that and generally jurisdictions do not force you to update unless it was so bad that they condemned it. However all new additions / wiring must meet current code. Even the switches used back then are not today's standard, the identification of the common screw on a 3 way switch was not as easy to identify as with new switches.

          Are you located in the United States or Canada?

          changing to plastic covers and non metallic screws on the faceplate will add to safety but not necessary fix the issue though. If you like we can try and sort some of this out but we will need to basically draw a picture of how it is wired, and to do that I would need to know have an inventory of what is in each electrical box and which wires are connected to what screws and so on, if you would like to do that I will give you a list of things to check and reply to us on similar to what was done on a previous thread with jbanks.

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