help with 3way switches - Elec.

[430752]

Okay, I bought an older home a few months ago (1920's). Not my first such pruchase, but this home is a bit more involved than the last.

The latest project involves figuring out one or two things. It may one thing, may not.

THere is an outlet above the mantel fireplace that doesn't work. I've taken the plate off and checked it out, all seems good. Nevetheless, I replaced the receptable (2 prong only) with a new 3 prong and properly grounded. I ground through the box since using BX cable, if it matters. Like I said, all appears good from a look inside the box, meaning as old as the cabling is (copper with nickle plating, bakelite insulator, wrapped in cotton woven jacket), its in god shape, properly seated, etc. True, I have no idea what happens outside the box, but by all indications it was done properly the first time.

Yet, no power to the outlet.

Okay, elsewhere in the foyer there is a missing switch which upon opening the faceplate shows what should be a 3 way switch. That is, there is a white, black, and black with red stripe (kinda hard to tell when looking at 80+ year old faded cotten jacket cabling, but pretty darn sure). This one was not connected, just 3 wires closed-off for what passed for electrical tape back in the day (e.g. a cotton based elec. tape, not vinyl like nowadays).

Elsewhere, about 20 feet away, is another switch box which also shows what should be a 3 way switch, again 3 wires, this time one white, one black and one red (not black with red stripe). Anyway, not connected. So, I assume these two potential 3 ways are or should be connected. There is precedence for this as the house has at least 4 other three-ways in it, a big feat back in the day I imagine.

No, no gurantee the not-working outlet above the mantel is connected to the three ways, but all other switches and outlets in the house work, except these. And yes, as mildly odd as it is to have a switch control an outlet, the house has at least 2 of them as well (although, not controlled by a 3 way, just a single pole in each instance).

Anyway, trying to figure it all out, I connect the two 3-way switches as best I can figure out (treating the red/black with red stripe as the traveller, connecting the whites at the same terminal on each). Well, I get it all hooked up and no luck. I use a test device (small bulb with two pigtail leads) and can't get power across any of the terminals. No indication I've done anything right or that there is even power. Yes, I've tried tracing the lines, but in the basement cieling I lose sense of them, other than to say that it is wholly probable (but not proven) the switches are connected to the outlet judging by the where the lines have junctions and where they lead.


So, how can I know or test which lead goes to which terminal in a 3 way? Anyway to know if I've treated the whites, or the travellers correctly? I've put the "whites" to the same terminal in each 3 way, and reversed the blacks and reds between the two. COuld be they just don't work, but could it be that I've just got them hooked up wrong? Or, even if hooked up wrong, should I get some positive signal? Again, not sure the outlet is connected to the 3ways, but no other outlet/fixture is unspoken for, so to speak.

So, any help on how to troubleshoot? How to know if they work or if Its just misconnected? Any idea on what to look for for hints on hot wire properly? etc. etc. Hope I've given enough of a description to make sense, if not I can clarify.

[LCHIEN]

there's three ways i can think of offhand.
First are you sure all leads are "dead" If not, best do this with the main house breaker turned off.

1, you can buy a signal tracer designed to be clipped to a wire somewhere in the house and a companion signal detector that will beep to alert you you have touched a wire connected to the same circuit. that costs money but i think the local hardware stores will have them. {PS - aparently not}

2. you can buy some hookup wire, can be the small gauge doorbell wire or speaker wire or even single conductor hookup wire. Use a wire nut to attach it to a wire at one box. run it to the wall switch box, use your ohm meter to check continuity between the end f the test wire and the other wires in the box.

3. This is the hardest way, you can literally tie wires you think you know should be present at both ends, together at one end, and then check continuity between the two wires at the other end (using the ohm meter). That won't check all the wires but can put to rest some doubts you may have.

[just started]

First of all, do ANY of the wires have any voltage to ground? I have seen outlets high on the mantel wall that were switch controlled but never with a 3-way.

You can get the gadget Loring mentioned fairly cheap, but make sure it has it's own power source. Some of them are made to work from the line power they are plugged into.

[eccentrictinkerer]

there's three ways i can think of offhand.
First are you sure all leads are "dead" If not, best do this with the main house breaker turned off.

1, you can buy a signal tracer designed to be clipped to a wire somewhere in the house and a companion signal detector that will beep to alert you you have touched a wire connected to the same circuit. that costs money but i think the local hardware stores will have them. {PS - aparently not}
2. you can buy some hookup wire, can be the small gauge doorbell wire or speaker wire or even single conductor hookup wire. Use a wire nut to attach it to a wire at one box. run it to the wall switch box, use your ohm meter to check continuity between the end f the test wire and the other wires in the box.

3. This is the hardest way, you can literally tie wires you think you know should be present at both ends, together at one end, and then check continuity between the two wires at the other end (using the ohm meter). That won't check all the wires but can put to rest some doubts you may have.

I found this at Harbor Freight for $19. It works just as good as the $90 unit at the BORG.

It takes some getting used to but can really help track those mystery wires.

Good luck!
http://www.harborfreight.com/cpi/cta...emnumber=94181

[RAFlorida]

As was posted earlier, make sure that NONE of the

wires have voltage to ground. As it being BX cable, I would not rely on that wire/sheithing be a good conductor because of age can cause a bad connection some where down the line. If there's no voltage, you can do as Loring states. You're going to be a detective and trace EACH wire for what it does. Many different electricians (and non-electricians) use different schemes for what is the travelers and which will be the common. By tying a small gauge wire in to one of the supposed switches and using an ohm meter, check to see if they do in deed go to the mantle recept and to the other switch. I take it that you know enough about 3-ways to remember that the commons are the source and the termination points, so you can eliminate those quickly between the switches. I doubt that my input will help any more than what's posted, it's really just repeating; but the thing I'm trying to make is, make a drawning of what you find by using the ohm meter. Hope you luck in figuring it out. (BTW, only once in 50 years have I seen a mantle recept 3-way controlled. About ten years ago a couple wanted a small lamp to turn on at the mantle when entering the den from either of the two entrances.)

[430752]

Thanks

I may try the HF detector. But, by the way, how does it trace wires with specificity since, in the end, all wires are connected to one another through the main box? I assume jit is ust a low volt that isn't strong enough to make it past a few junctions?

Yeah, I'm not too sure the 3 way is connected to the mantle outlet either. But, I've found no other unused outlets or ceiling fixtures, and the home doesn't appear to have had any major work done on it ever. And, the mantle is the only non-working outlet I've found. Plus, since there are no ceiling fixtures or even sconces in the whole of the living room (and a pretty big LR too, about 12x25) the mantle outlet seems like it could have been designed to serve as the light at the "head" of the LR. Of course, why not a scone I dunno, maybe once was a scone, but no evidence of that either (e.g. paint rings, scratches, indentations on wall, etc.)

thanks again, will have to wait until upcoming weekend to check due to schedule.

[RAFlorida]

Your guestion about how the wires all feed back to a

central location. In all older house the neutral and ground will be common at the panel. New house will have generally isolated neutral. BUT the hot wire(s), any color other than white, green or bare, will go to either a breaker or fuse. If that OC device is off or unscrewed, then it deadends right there. Because most circuits are parallel, there may be other devices in that ciruit. Just remember to id your travelers, seperate all wires, turn OC on and find the hot at one of the 3-ways, then at the other switch that doesn't have a hot showing, see if that common goes to the mantle recept with your ohm meter. If so, then you've solved the circuit.
I agree with you about the most likely wiring being as you noted, no other light fixtures, etc.
edit: OC is Over Current protection, fuse, breaker.