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-   -   a wiring mystery (http://www.diychatroom.com/f18/wiring-mystery-54366/)

jgm156 10-03-2009 05:24 PM

a wiring mystery
 
my project started out as a simple lighting fixture change and now i'm in a real state of confusion. i'll try to explain as clearly as i can and hopefully someone will understand and help me finish this job...

1. i'm trying to swap an old lighting fixture for a newer one.
2. the fixture is controlled by a dimmer switch (the round kind).
3. i've removed the fixture as well as the switch (yes, i remember which wires went where).
4. the junction box in the ceiling has three wires. two white wires and a green wire. none of these wires are hot (i tested them several times).
5. the switch junction box has one black wire and one green wire (the black wire is hot)
6. there is a switch for another lighting fixture on the opposite wall, which is where i believe the black wire is getting it's power from.
7. when i removed the old fixture, all wires were connected. the two white wires in the box were connected to the two fixture wires with one large wire nut. the green wire from the box was connected to the green wire from the fixture.
8. when i removed the dimmer, the old dimmer had two black wires coming from the back. one was connected to the black wire in the switch box and one was connected to the green wire in the switch box.
9. i am terribly confused.
10. i've swapped many a fixtures, but i've never seen anything like this before!

i'm trying to remember if there is anything else, but i think that's all. please help. thanks.

gregzoll 10-03-2009 06:48 PM

What you have there is a mess. Each box should have a White, Black, and Green (ground). Now, if you had a "Switch" leg into the box for the light, it should have had at least black tape or black marker on the White wires, but one has to tie into the Black wire some where.

jgm156 10-03-2009 06:55 PM

a mess is right
 
2 Attachment(s)
i just took a few pics to clarify the situation. in the first picture (the ceiling), none of the white wires are hot. in the second picture (the wall switch), the black wire is hot. any guidance would be greatly appreciated.

gregzoll 10-03-2009 07:08 PM

Even if that is the case, where is the white wires in the Switch box? The black would be on either side of the Switch, or Single Pole Dimmer, and as for the ceiling light, where does the extra White goes? Again, this is a mess, and how many other rooms have this nightmare? I would not be surprised if you did not find hidden Junctions, and splices behind the Gypsum/Plaster.

hayewe farm 10-03-2009 07:10 PM

Guess a guess but I would say some one had a lot of wire on hand and didn't follow convention. My guess would be that the two black wire goes to one side of the switch providing power to the switch and out-feed power to possiblely an outlet, the green wire goes to the other side of the switch and provide power to the light(connect to black lead of light) the 2 yellow wires are common to the light and out-feed common to an outlet (connect together and to white wire on light) Just a guess, have a fire extinguisher handy.

jgm156 10-03-2009 07:20 PM

1 Attachment(s)
there are some white wires in the box. i think that the white wire in the box is coming from the switch on the other side of the wall -> nutted to another white wire -> sent up to the junction box in the ceiling... here's a pic of inside the box on the wall.

PaliBob 10-03-2009 07:21 PM

Everybody knows that Green is ground, except it was not always that way. Codes in the 50's did not reserve Green as the color for the EGC.

I think your 'Green' wire is the switch leg. Check it

.

jgm156 10-03-2009 07:32 PM

really appreciate the replies and the reassurance that this is in fact a real mess! however, i'm a little uncertain of some of the terminology in the suggestions...

the green may be the switch leg? ok. how can i test this and if it is the switch leg, what does that mean for getting my new fixture up and running?

also, it may appear in the picture that there are two black wires in the wall box, but it is in fact one wire folded in half. the bare section is the bending point. not sure if this makes any difference, but i'm totally lost and want to provide as much detail as possibe. thanks again.

hayewe farm 10-03-2009 07:45 PM

In the switch box you have the black wire, it was connected to the switch and is most likely the hot to the switch, the green wire was connted to the other side of the swirch it provides hot to the light when the switch is turned on so it is switched on and off or called the switched leg.

jgm156 10-03-2009 07:53 PM

Quote:

Originally Posted by hayewe farm (Post 335996)
In the switch box you have the black wire, it was connected to the switch and is most likely the hot to the switch, the green wire was connted to the other side of the swirch it provides hot to the light when the switch is turned on so it is switched on and off or called the switched leg.


thanks for the clarification. makes sense. now on to getting this mess sorted.

i think i'm clear on how i should connect the switch wires. there are two black wires coming out of the dimmer and one will get connected to the black wire and the other will get connected to the green wire. i'm assuming this means i am going to ignore the ground wire on the dimmer?

the one thing i still need some insight on is how to attach the new fixture to the ceiling box.

thanks again.

hayewe farm 10-03-2009 08:02 PM

Black light wire to green, white light wire to the 2 yellow wires.

jgm156 10-03-2009 08:15 PM

Quote:

Originally Posted by hayewe farm (Post 336007)
Black light wire to green, white light wire to the 2 yellow wires.

ding! ding! ding! we have a winner!!!

thanks a bunch. fixture is working. all wires are correctly nutted together and labeled. hope i never see something like this again. thanks again. just out of curiosity, is this a common wiring scenario?

PaliBob 10-03-2009 08:31 PM

1 Attachment(s)
jgm, Your wiring is not a 'Mess' it is just normal for some older installations.

1950's conduit did not usually have an EGC as shown in the attached Pic.

Your dimmer does not need a ground to work properly.

The pictured ground Clips are available almost everywhere.

.

connyou 10-04-2009 12:01 AM

There is nothing wrong with that at all. It is not even close to a mess. It is the exact same way we would do it now. Except for the green switch leg. Electrician probably had a piece of green the right length and didn't want to waste it. Or it has been repulled at a different time.

The wires at the fixture are white, not yellow. Your neutral. That neutral is just passing through. Your pipe is the ground. Screw in a gound pigtail or clip it. Tape the green wire black. Black to black, white to white.

At the switch you don't need a neutral or ground. Don't need it, it is not pulled. The black hot looked looped. Cut it, strip it, pigtail it, land it on the top of the sp switch or nut it to one leg of the dimmer. Tape your green switch leg black land or nut that. Screw it all back together, turn on the light.

And next time, if you're not sure, call an electrician. There are a lot of us out of work.

jgm156 10-04-2009 12:37 AM

hey, thanks for the info. i see that you're an electrician and i certainly appreciate your enthusiasm. while you may not have been as perplexed as i was this wasn't a typical white, black & green wiring job.

in any event, i would have loved to have shelled out 100 bucks for a pro to come and do this for me, but all i would have gotten was a working light and 100 less dollars in my bank account. now, not only do i have a working light, but i also know how to do this next time and every time after that and i even saved myself a hundred bucks! you know what they say, you teach a man to fish...

thanks again.


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