Unknown light switches


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Old 11-11-12, 01:38 AM
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Unknown light switches

Hello,

I bought a new house, and there are 4 light switch (From 2 diff areas) which I have no idea where it goes, and what it controls. (I have tried sockets, different lights...etc... no luck) I am guessing it is the flood light on the side of the house in backyard, becuase I still have not found where is the light switch for the 2 motion sensing flood lights i have.

I have opened the switch plate, and have measured the voltages - it does have power - i just dont know what it controls.

Q1) What will be the best way to trace this wire at the switch plate to find out what it controls? (I can crawl around the attic) (From the switch - find the fixture it controls)

And there are 2 sets of flood light in the side of the house in backyard area. I have taken the flood light fixtures apart, and measure the elect. There are NO power going through it no matter which light switch i flip on/off. I am 'suspecting' that 2 of the 4 unknown light switches actually controls it, but i cannot understand why that wire at the floodlight has no power when i flip it on/off.

Q2) What would be the best way to trace this problem? (from light fixture - find the switch)

Thanks!
 
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Old 11-11-12, 02:13 AM
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Tell us all the wiring at the switches and the lights. When you checked receptacles did you check both plug-ins at every receptacle?
 
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Old 11-11-12, 10:45 AM
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I have opened the switch plate, and have measured the voltages - it does have power
Are the switches SPST (on/off) switches or 3-way switches?
 
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Old 11-11-12, 11:59 AM
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I have used my telecom tone and probe set to figure out where high voltage wires go, but I first physically unhooked things to ensure that I wouldn't hurt myself or blow out my tone generator. You can also use a multimeter continuity tester once you've unhooked the hot and neutral on the far side of the switch to see if you get continuity. If you do then there's probably a light or device there that comes on when power is applied, and if not then there could be a receptacle powered by that, or something that was powered by that has been removed.

I used my tone and probe set to figure out the actual order of the receptacles in my kitchen, so I could figure out where to put the GFCI outlet to protect the rest of the receptacles.

I too have one romex bundle that I don't know where it goes. In my case I suspect that two of my outside lights used to be on two separate switches but are now on one switch, but I'm not entirely sure. Either way, I took the switch (which had no supply side wiring) out, put small wire nuts on the wires, and put a decora blank plate in to cover the position.
 
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Old 11-11-12, 12:10 PM
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They are sPst.

There are 2 areas which i have switches which i dnt where it goes.

Area1) bedroom - there are 3 spst switches and 1 timer switch. All of them have power going thru it. Know one of the spst goes to the bedroom light. And i suspect the other 2 spst is for the outside backyard light. The timer switch, i suspect its an override for the 2 backyard light to turn them on based on timing.

Area2) livingroom. Threre are 4 switches. 2of them is spst, 2 of themis 3 way. I know the 3way is hallway switch, and entrance switch. One spst is for a utlet in living room. I do not know where the other spst goes.

Thx
 
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Old 11-11-12, 01:11 PM
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You still have not answered my questions in post #2. Answer those and we will go from there.

There is no reason to trace the path of the cable and that would be difficult even with expensive equipment. We only need to find where the cable begins and ends. My questions may answer that.
 
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Old 11-12-12, 09:54 PM
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Tell us all the wiring at the switches and the lights. When you checked receptacles did you check both plug-ins at every receptacle?
I checked both receptacles. it does not look like its receptacles.

For the wiring, can you let me know what information i should be providing? Sorry, i am not very good with the wirings. I can install things with hot/load wires..etc... Are you asking for info like, how many wires, which ones goes to which..etc?

For the lights, basically, there are total of 4 flood lights , one at each corner of the house. I am not able to find switches for any of them.

I cannot remember the wiring for the 2 front lights very well now. But i knwo the 2 back corner lights are interconnected. meaning, when the left back corner detected motion, it will light up, and also light up the right back corner as well.

If i remember correctly, the front works the same way, (but i remember there is something else to the 2 front light - which i cannot remember.) I need to climb up again this weekend to see.

Thanks.
 
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Old 11-13-12, 04:51 AM
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While you're up there this weekend, remember, bulbs made the same day at the same factory may die at the same approximate age, so carry you some light bulbs when you go. It would be best to replace them anyway unless you know they are fresh and good.
 
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Old 11-13-12, 05:08 AM
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Someone may have changed a formerly switched receptacle into a constant hot by not breaking the jumper on the brass side.

If you look behind the receptacle plates you may see both a black and a red conductor. this could possibly indicate a switched location.
 
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Old 11-13-12, 06:48 AM
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Q1) What will be the best way to trace this wire at the switch plate to find out what it controls? (

Q2) What would be the best way to trace this problem? (from light fixture - find the switch)

Well, I can give you the trick my father used when I was little:
Install a temporary outlet into the circuit you want to trace
(heavy duty alligator clips to a box outlet)
Plug in the oldest small motor you've got - old drill works well...
Get a transistor AM radio, stand by the outlet, and tune until the static is loudest.
Use the AM radio to follow the circuit by listening for the AM static emitted by the circuit which the motor is on.

There are "tracers" available for finding breaks in the invisible fence wires, they seem to be a more refined version of the AM radio trick.


Hal
 
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Old 11-13-12, 12:14 PM
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Sounds like a lot of unsafe work for testing a circuit that can be traced using conventional methods. I find breaks in fence wires by looking for cows out. That's usually where the break is
 
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Old 11-13-12, 12:49 PM
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Originally Posted by chandler
Sounds like a lot of unsafe work for testing a circuit that can be traced using conventional methods.
True -

but, depends on "conventional methods"

Curious now, what IS the "conventional method" to locate a hidden box on a joist
say, in a room with a 12" crawl space where there's a 2nd wood floor laid 90 degrees over the origional?

Or wiring in a masonry wall, common situation is BX threaded between the stone and plastered over?

Hal
 
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Old 11-13-12, 12:54 PM
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If those scenarios exist, it is usually better to rewire the circuit, since all the hidden boxes are not code worthy to begin with. My comments were mainly for the alligator clips in exposed areas. And, tone tracers are much easier to use, IMO. Of course if you have power at one receptacle, and not at the next, you can just about bet the wiring between is suspect.
 
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Old 11-13-12, 06:14 PM
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I know you said that you checked all of the receptacles - but did you check each outlet top and bottom? I had a 'mystery' switch as well and couldn't figure out what it controlled. It wasn't until months later I discovered that the switch actually controlled only the top plug in two outlet receptacle. Since the mystery plug is located in a living area I think it's designed to control a floor lamp from the switch on the wall. Find a table lamp and recheck your outlets if you haven't done this to be sure.
 
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Old 11-13-12, 07:32 PM
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I know you said that you checked all of the receptacles - but did you check each outlet top and bottom?
Yes, i have checked both top and bottom.

I will get some pictures of wiring and fixtures this weekend.

thanks
 
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Old 11-15-12, 12:39 PM
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I checked both receptacles. it does not look like its receptacles.
You checked to see whether they're working, or you checked to see how they're wired?

For the wiring, can you let me know what information i should be providing? Are you asking for info like, how many wires, which ones goes to which..etc?
Essentially yes. In each box, tell us the number of cables that enter that box, how many wires - by color - are in each cable, and how each wire is terminated or spliced. There is no need to include bare ground wires in your description. We will assume one ground wire in each cable unless you tell us it is missing.

Pictures might help, if they are taken with the switches and receptacles pulled forward and the wires straightened enough for the colors and connections to be seen clearly. How To Include Pictures

What breakers supply the outside floods? Are they on the same circuits as the switches your trying to diagnose?
 
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Old 11-16-12, 01:05 AM
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What breakers supply the outside floods? Are they on the same circuits as the switches your trying to diagnose?
I was never able to get the floods to light up. so i do not know what breaker it is in.

I will get some pictures of the switches this weekend - by pulling the switch foward, and describing the wiring.

Also, for the recepticle question - i tested the socket to confirm that it is not controled by the light switches. I did not open the receptible to see how they are wired. As i do not know which one it could control, i did not open all of them to see.
 
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Old 11-16-12, 07:32 AM
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I did not open the receptible to see how they are wired. As i do not know which one it could control, i did not open all of them to see.
You can't skip steps. Opening all the receptacles is necessary grunt work unless you want to hire an electrician to do it. Start in the room with the switches and receptacle nearest to the switch and work out from there.
 
 

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