New house, 3 switches and 1 light

Hi
My name is Kris and am looking forward to learning from this site.

I recently bought a house and have 3 light switches I can't figure out what they operate and 1 light that won't turn on. I have one switch that appears to be wired as a 3 way switch in my downstairs by a patio door. I have 2 switches side by side ( by upstairs patio door)that were wired at some point but the wires are capped and not hooked up. I have a flood light that does not turn on and has new bulbs. I would assume that one switch upstairs and the one downstairs are the ones that should be wired as 3 way to operate the outside flood lights. Is there a way to verify this or can I eliminate the 3 way and have just one switch operate the lights? Where do I start?

Thanks in advance!

 

Normally the outdoor floodlight is operated from a single switch and usually this switch is at the door closes to the light.

You need to do circuit tracing. Get a multimeter and a long length of wire. urn off the power. Unscrew the bulb. Attach (an alligator clip is suggested) the wire to the contact at the bottom of the socket. At a switch in question, do an ohms (resistance) measurement between the other end of the long wire and the contacts of the switch. When you get a zero ohms (no resistance) reading you have found a switch connected to the light. Caution: Due to the possibility of loose connections, simple measurements of this kind are not foolproof.

A 3 way switch has 3 wires attached to it, not counting the bare wire attached to the metal frame (bracket, yoke). a "regular" switch has 2 wires.

 

A toner called a Fox and Hound can also be useful for tracing wires in the walls. It injects a tone that the receiver can pickup along the path of the wiring.

 

Welcome to the forums!

Whether there are any wires attached to it or not, a 3-way switch has three current-carrying terminals (i.e., not counting the terminal for a ground wire). One, usually black or dark, is the common terminal. The other two, usually bright brass, are traveler terminals. In addition, if a 3-way is to be used as a 3-way, there must be either a 3-conductor cable entering the box with all of its insulated wires attached to the switch, or both a 3-conductor and a 2-conductor cable with one insulated wire from each cable spliced together and the other three insulated wires attached to the switch. Is this what you see by your downstairs patio door?

Yes. Start by pulling the two upstairs switches out of the box. Note whether they are two "regular" switches, two 3-way switches, or one of each. If they are one of each, note the location of each type in the box. Note the number of cables entering the box and the number of wires, by color, in each.

Thus the power off. Pull the downstairs switch far enough out of its box to see the cables entering that box and how the wires in each cable are attached (spliced or terminated). Post back with what you see in each box. Also tell us where the flood light is located relative to the two switch boxes.

If you think pictures might help us, see How To Include Pictures.

You may need to test for continuity at some point, but not yet.

 

Thanks for the replies! Here is the outside picture. The light is above the lower sliding glass door

 

Theses are the pictures of the 2 unhooked switches upstairs which are by the sliding door.

 

Here are the pics of the lower switched that is hooked up but doesn't turn anything on

 

Judging by the pictures, it looks like the switch downstairs is just the switch. (what we call the travellers and the return)
Upstairs it looks like the feed goes into that box, as well as the cable going to the light?

Here's how I'd have you try and find out which three wire plus ground goes downstairs, using a multi-meter, that is assuming you have one.

The best way to do this safely, and ensuring you don't hurt yourself or others is to do this with the power OFF. Otherwise, do not proceed with these instructions.
Then use the multi-meter set to volts to verify that it's off. Double checking never hurt anyone, forgetting to check has killed or hurt too many.

No voltage? good, now you can use the multi-meter set to ohms to check the three wire cables for zero ohms between white and black, white and red, and red and black (of the same cable) then test the second cable. Make notes of what you find.

Then go downstairs and flip the switch, go back upstairs and check again for voltage to be safe, then check again for zero ohms, and again make notes. You should be able to figure out which cable goes to the switch downstairs.

Next step would be to figure out which cables go to the light fixture, and which cable is the feed.

Edit: I'd suggest getting a book from Home Depot, Electrical Code Simplified by P.S. Knight. Very good book for the layman showing how house wiring is done correctly, and it's the book we used in basic level trade school.
PS Knight | ON Electrical Code Simplified BK 1 | Home Depot Canada

 

Or in the US Wiring Simplified available on Amazon and in the electrical aisle of some big box stores.

 

OK to figure out which cable is the feed, which is the light fixture(s) you can do this.
Again, with the power off.

About 2" from the joint, tape together each pair of insulated wires that are already connected with wire connectors, so you don't loose how it's wired up now.

Next, (leave your ground wires connected) open the connections and cap each and every wire individually. We can't have exposed live wires.

With all the wires capped and safe, you can turn the power on, if you have a non contact tester, use that to determine which wire is hot / live. If you don't have the contact tester using the multi-meter set to volts.
hang / place the meter up where you can see it, connect one lead to ground, put one hand in your pocket and CAREFULLY test for voltage on each wire, and then replace the wire connector. record your results, mark any wire that shows voltage with a piece of different coloured tape or a bread tag.
(Most likely it will be the black wire of one of the two wire plus ground, but if isn't don't fret.)

Turn off the power, and check with non contact tester or multimeter before you do an ohm check.

With that done, you will need to find out which cable goes to your light.
One of the other two wire plus ground cables should have a resistance reading near zero (assuming the lamp is not burned out) if the lamp is burned out, this could be part of your problem.

Finally, you need to label each cable; one through five in the box with loose wires, and you let us know which cable was switched, which cable was light fixture, and which cable was feed. I can find or make a diagram to help you get it back together.

 

Thank you for the pictures. They provide some information, but my original request wasThe suggestion about pictures was in case you wanted to add them in addition to the wiring descriptions. I regret that I wasn't clearer about that.

Let's see what we have now:

• We know where the light is relative to the lower door.
• We know that the mystery switch at that door is a 3-way switch that has black, red and white wires terminated to it, that the red wire is connected to one of the traveler terminals and that switch is one of three in a 3-gang box.
• We know that the two disconnected switches upstairs are mounted in a 2-gang box that's directly above a second 2-gang box that also has two switches mounted in it. We know that one of the disconnected switches is a 3-way. We know that three 2-conductor and two 3-conductor cables enter the box where the disconnected switches are mounted, that three of the white wires are spliced together, that the other two white wires are each splices to one of the black wires, and that the other three black wires and the two red wires are all capped off.

Here's what we don't yet have:

• In the basement, we don't know what the other two switches in the box do, what cables and wires enter that box, or how the wires are connected. In particular, we don't know whether the three wires connected to the mystery switch are in one cable or more than one, and we don't know which terminals the black and white wires are connected to. Where power enters this box.
• On the main floor, we don't know where the two 2-gang switch boxes are located. We don't know whether both switches in the upper box are 3-ways, or only one. We don't know what the two switches switches in the lower box control, and we don't know where power enters the upper box.

Reasonable Guesses:

• The switch in the basement is a dead-end 3-way. The white wire is on the common terminal. It is carrying ungrounded potential, without being tagged, and is one of the two white wires spliced to black wires in the box with the two disconnected switches. The intended function of this switch is to be one half of a pair that control the outside flood light.
• On the main floor, the two 2-gang boxes are to the right of the sliding door to the deck. One of the three 2-conductor cables brings a complete circuit from the panel and one feeds out to the outside floodlight. One of the two 3-conductor cables goes to the 3-way switch in the basement.
• Both of the disconnected switches are 3-ways.

Problems with the guesses:

• We still don't know what the other two cables and one switch on the main floor might be intended to do, and
• If these assumptions are accurate and the correct wires are spliced together in the upper upstairs box, the 3-way switch in the basement would function as an on/off switch for the outside light. It isn't, so one of the assumptions is wrong or one of the conditions isn't met.

Hmmmm...

The most likely problem with the guesses is that one of the conditions isn't met, and that that condition is that "the correct wires are spliced together."

Here's the thought: There are only three splices in that box. For the light to be powered there will have to be a fourth splice, connecting one of the travelers from the downstairs switch to the hot feed for the light.

OK, next best steps:

1. First, Bristol, confirm that the two white wires that are spliced to the two black wires in the upstairs box are the white wires in the two 3-conductor cables, the black wires in those two splices are each from a 2-conductor cable, and the three white wires spliced together are from the three 2-conductor cables.
3. If this isn't the case, please post back immediately with the accurate observation.
5. If this is the case, separate the single capped wires so that the black and red pair from each 3-conductor cable are near each other and the third black wire, from a 2-conductor cable, is in a different position. That should be the hot feed wire for the light.
7. Next, confirm that the wire connected to the common terminal on the basement switch is white.
9. If this isn't the case, please post back immediately with the accurate observation.
11. If this is the case, use a multimeter, preferably an analog one, to test for voltage between the common terminal on that switch and the (presumably) grounded metal box.
13. If you don't see 120V (+) there, please post back immediately with the accurate observation.
15. If you do see 120V (+) there, test for voltage between the box and each traveler terminal on the switch. One of them will have 120V and the other one will have ~0V. Note the color of the wire connected to the terminal with 120V showing.
17. Back upstairs, uncap the black and red wires from one of the 3-conductor cables and test for voltage between each wire and the grounded box. If that test matches the result you got downstairs, you can turn the power off and splice the traveler with power to the black wire that you identified as the likely feed for the outside light. Personally, I would test the two travelers in the other 3-conductou cable first, to make sure I didn't see the same result.
19. If the results from testing the travelers in the two 3-conductor cables are the same, go flip the downstairs switch and test upstairs again. Now you'll know which 3-conductor cable is connected to the downstairs switch. Mark that cable - the set of wires in that cable.
21. Now, turn the power off and temporarily splice (with a wire nut) either of the two travelers in that cable to the black feed wire for the outside light. Turn the power back on and see if the switch in the basement now turns the outside light off and on.
23. If it doesn't, please post back immediately with the accurate observation.
25. If it does, turn the power off again. Mount the switch in the basement and put the cover back on the box.
27. Upstairs, take that temporary splice apart. Terminate the black wire that feeds the outside light to the common terminal on a 3-way switch. Terminate the black and red wires in the cable going to the basement switch to the two traveler terminals on that switch. Mount that switch in the position closer to the door.

Tomorrow we can troubleshoot the remaining switch. It's probably for inside lights.

NOTE: I've made a number of assumptions in going through this. Any one of those could be wrong. That's why I inserted the "please post back immediately" points. Not posting back when something doesn't go as planned, and trying to reason through it, might confuse the process. Please, do let us know if any step gives an unexpected result. If I'm not here, there are others who likely will be, and who can help you figure out the best next step from there.

 

Each white wire that is spliced to a black wire comes from 2 separate 3-conductor cables (red,black,white)
The 2 black wires come from the same opening along with 2 white wires
For the 3 white wires spliced together..... 1 white wires comes from a 2-conductor cable while the other 2 white wires come from the same opening (2 white and 2 black wires)

 

OK, that's confirmed.

There are only 2-conductor cables (1 black and 1 white) and 3-conductor cables (black, red, white) in your installation. Two of the 2-conductor cables may have been fed through the same opening. That's done sometimes. So we can read this as yes, the black wires in those two splices are each from a 2-conductor cable. That's confirmed.

Great. The three white wires spliced together are from the three 2-conductor cables. (That the two white wires that are spliced to black wires are from the two 3-conductor cables confirms this too.)

You're ready to move on to step 3.

First, though, take a minute to tag each of the spliced white wires with a bit of electrical tape or permanent marker to show that they are carrying ungrounded potential (they're repurposed as "hot wires.") You can use red, black or any color except gray or green to to this. If you use a different color on each it will help keep their identities separate going forward.

 

Done.
Done and confirmed.

I will borrow a multimeter ASAP

Thanks again