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switched three way neutral

Discussion in 'Question of the Day' started by ship, Jul 28, 2008.

  1. ship

    ship Senior Team Emeritus Premium Member

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    Been working a lot lately at a 1950's house lately.

    So been working the last like three months when ever available there doing anything from making windows to re-wiring the place in working with the electrician and contractors doing their own thing including at one point even removing an entire section of the place I just did a few less involved parts of it. Long story.

    Anyway, what’s left of mystery for me is the garage. Rewired a few outlets but was based with a huge question that as yet is still not answered - this as with where the power for the garage comes from (theorized kitchen threeway switch was in theory removed during the wiring and is TBA in what's up with it.) This seeming three way switch somewhere in a back of house kitchen switch in somehow controlling a part of it yet not other parts of the garage - how it is wired into the system. Got a basic understanding of what was done but not so much anything I am thinking should work properly sufficiently especially given the threeway was removed during construction and only at best if any two legs of the tree way were connected..

    Somewhere no doubt in the kitchen is the components of a three way switch that works in combination with the threeway in the garage for it’s exterior lights. Yet feeding the garage with its various outlets and garage door opener, you have steady power. Only three wires coming into the building however and near as I can tell, that three way switch both in the garage and somewhere in the house is switching the neutral and jumping it to tap the Edison type outlets for the rest of the garage.

    How does something like that work in it being original to the building and is it still current code to do so?

    Threeway switches - one in the garage found so far is definaltely the first stop for the incoming feeder wire in it feeding than after after a link all else on the neutral side, the other in the house somewhere I don’t yet know about yet. Currently, with the kitchen under construction, I think it’s in a wall box and the outside lights are off at the moment yet the power to the garage is ok.

    On the outlet to the outside lights I get a power sniffed hot, and no neutral to them in completing the circuit.

    So we have the neutral as a sort of traveler component of a three way switch and on the supply side it bridged in supplying the outlets inside the garage so it don’t matter what pole it’s on.

    Explain this and etc. in concept, why they did it that way instead of pulling another wire and or how or how not it might not be say safe.. This beyond some grandstanding concept of proper safety = remember this was wired in like the 1950's and has not burned down yet or has hope of doing so in the future without changing the wiring.
     
    Last edited: Jul 30, 2008
  2. TimMiller

    TimMiller Well-Known Member

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    In three way switches you can run a 3 wire cable from one switch to another and use the neutral as a traveler, as long as you mark it as a current carrying conductor. But in no way can it be used as a neutral. I'm really betting that there is another wire that is feeding the plugs in the garage. If you were to wire the plugs off of a traveler, one will always be hot the other will always be cold, so the plugs will only be on when the light is on, or the plugs will only be on when the light is off, depending upon which traveler, and the orentation of the switches. From your description i bet this is how it is wired
    3-way Switch Option #3 - The Home Improvement Web Directory
    It costs more to pull another wire, than to just use one you already have. It also makes more since.
     
  3. n1ist

    n1ist Well-Known Member

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    This is often called the "california 3-way" or similar. The trick is to wire the 3-ways backwards with hot and neutral feeding the poles normally used as travellers and connecting the light betwen the two commons. That way, the cable running to the garage has hot, neutral, and switched. It takes advantage of the light being off when both terminals are hot. Not safe (the bulb is out, but the screwshell is hot).

    See [media]http://i125.photobucket.com/albums/p66/JohnJ0906/carter.gif[/media] for a picture of this I found on the web.

    /mike
     
  4. TimMiller

    TimMiller Well-Known Member

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    WOW, i have not seen that done. I'm sure that is definately not to code. Time to do some research.
     
  5. RichMoore

    RichMoore Member

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  6. ship

    ship Senior Team Emeritus Premium Member

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    Revised my first post. Nope on the second website/option, it was the neutral that was switched on the traveler lines. Off the threeway switch in the garage the neutral had a second tap off each pole which was combined in a wire nut with the neutral feeding the outlets. The hot in no place touched a switch.

    This way neutrals for the garage no matter what position either threeway switch was at, would get constant power, only in theory the lights were switched.

    First photo I couldn't open but sounds like an idea possibly.
     
  7. TimMiller

    TimMiller Well-Known Member

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    Try this ship
    [media]http://www.homeimprovementweb.com/information/images/wiring3l.jpg[/media]
     
  8. ship

    ship Senior Team Emeritus Premium Member

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    Yep, still wouldn't open.

    Still sufficient in diagrams and ringers as it were to understand how its wired I hope? So what in description is going on and how to change with out rewiring on a budget to make it proper if not?
     
  9. n1ist

    n1ist Well-Known Member

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    Let me try posting the URL so you can cut-and-paste. They probably started out with a normal 3-way to run the lights, and later on decided they wanted an outlet so they rewired with the existing cable, rather than pulling an additional circuit. Another code requirement to keep in mind is the need for separate ground rods at the garage if more than 1 circuit goes between it and the house.

    i125.photobucket.com/albums/p66/JohnJ0906/carter.gif

    Probably the easiest way to fix this is to rewire the circuit to be allways-on and use X-10 or some other carrier-current or wireless switching system to control the lights. The other way is to pull an additional circuit for power (you may want to upsize this so you can put a subpanel in the garage) and add the appropriate grounding.

    /mike
     
  10. TimMiller

    TimMiller Well-Known Member

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    Where in the code does it state that you need separate grounding in the garage. I have never seen nor heard of this. What makes the garage different than any other part of the house? If your house is grounded, than the ground wire is just fed to the panel board and grounded to an earth ground from there.
     
  11. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Detached garage, Tim. Not connected to the house. What most codes would classify as outbuildings.
     
  12. ship

    ship Senior Team Emeritus Premium Member

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    Hmm, easiest way would be for the outside garage lights to be single pole switch controlled from the kitchen. Simply fascinating the drawing = really fascinating. Don't think that's what has been done in somewhat chasing down the wiring and scratching my head a lot, instead I believe its a neutral tap off the garage three way in getting common wire - drew it out at one point but don't remember very well.

    Still fascinating, never thought of something like that - probably best that I had not even considered such a thing.

    Next time I'm in the garage - if I do any more wiring I'll have to have a look. IN the mean time I forwarded the drawing to the electrician re-wiring the electrician for him to further investigate / correct or at least aid in not screwing up it functioning.

    Thanks a bunch - fascinating.

    On the other stuff... resale property safe / simple / cheap = good, other options were I or they living there would be the option.

    Heck, I still cannot figure out where in the house this garage is fed from and I have been all over it except for in the kitchen. Do know breaker #2 feeds most of the basement, half the kitchen, a few other room outlets and the garage. Hopefully the electrician did some rewiring of that circuit since I did the initial mapping of the system & he added the sub-panel.
     
  13. ship

    ship Senior Team Emeritus Premium Member

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    Not going to get into that... what me... no idea - if I had an idea or had even ever been to this building, I would also consider the #14 wire feeding to be a wee undersided for such a classification. See nothing, know nothing - all I did was change two outlets to GFCI in the garage and that's about as far as I'm going with it. Were it for me with a real garage there would be a sub-panel, three phases of at least 40A. Heck, even my condo with one car garage has two 20A circuits. This otherwise it would tend to go dark if using power tool or saw at the same time the compressor comes on...

    Still, having read the basically a book on electrical contractor ethics "Old Electrical Wiring" (darned good book), I have to put it in one of those classifications that I have reported to the owners something that while not going to burn down is something not up to snuff / kind of wierd in how it was done. This has also been reported to the electrical contractor that's pulling the permit for part of the place. After those two primary sources have been informed and understand, my hands are clean. Garage powers up three work lights clipped to the ceiling rated at 150w, a radio, fan, 60w light and 15A table saw all at once at times but not static load. After done with construction, the next person owning the place if they want to do more should no doubt run new power to the garage, this insulate it etc.
     

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