On site, three-way switch holding me up!

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Old 10-26-16, 10:36 AM
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On site, three-way switch holding me up!

I am finishing the drywall on the ceiling and I just realized that I'm about to cover this unwired junction box that controls a light from two three-way switches. My internet is barely working and I haven't been able to figure this out. Can anyone help me solve this puzzle so I can get the last piece of drywall in place? Thanks!!

 
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Old 10-26-16, 11:01 AM
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As long as you have the 2) three wire cables in the box..... go ahead and sheetrock.
The connections can be made after the rock is up.

Is the wiring completed at the switches.... are the switches installed ?
 
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Old 10-26-16, 12:00 PM
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The junction box is in the shallow attic and will not be accessible once the drywall is installed. I can't cover this until I have a working system.

The switches are already installed and wired, as is the light.
 
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Old 10-26-16, 12:09 PM
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The junction box is in the shallow attic and will not be accessible once the drywall is installed.
Junction boxes must ALWAYS be accessible. You cannot "bury" them in drywall or any other material. You will need to have a blank cover on the box, either in the room or in the attic.

Are you asking what color wires to connect together and to the lamp fixture?
 
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Old 10-26-16, 12:19 PM
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Yes, I know that junction boxes need to be accessible and sealed, and this one will be, but barely. It will be ten million times easier to wire this now than to crawl through the attic access and shimmy down 20' of dirty, cramped attic space.

I was asked to replace some drywall after someone else removed a wall in a commercial building. The person who removed the wall left this junction box unwired and if I cover this now the lights won't work and only a very small, very light person would be able to reach this box. I did not create this situation, I am just trying to help the building owner get this unfinished job completed.

I have never installed three-way switches in my houses and I personally hate them. I don't have this knowledge and I need some help. I have gotten great support in the past from this community. Thanks guys!
 
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Old 10-26-16, 12:30 PM
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I usually don't respond to questions concerning three-way switches because they are so easy but I am in a good mood this morning.

At the switch where the power enters connect the two white leads together and insulate. Connect the black power to the black-colored screw of the switch. Connect the black and red wires of the three-wire cable to the two brass screws on the switch.

At the junction box connect the white from the powered switch to the white from the lamp fixture. Take the red and black wires from each three-wire cable and connect like colors, red to red and black to black. Insulate these connections. You should now have two free wires, a black from the lamp fixture and a white from the non-powered switch. Re-identify the white to some color other than white, grey or green using either plastic tape or permanent marker. Red or black is acceptable even though you already have those colors in use. Connect these two wires together and insulate.

At the non-powered switch connect the red and black wires to the two brass screws, one wire per screw and it doesn't matter which wire is to which screw. The remaining white is re-identified with the same color you used in the junction box and connected to the black screw of the switch.

All bare copper grounding wires are connected to each other.
 
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Old 10-26-16, 01:29 PM
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Furd, normally I would search and learn the solution, but this is a rare case where I'm in the middle of nowhere. I can use this app to post and read on this forum, but it takes a minute to load a new page on a browser so I'm super grateful for your help.

I'm going to wire it up and shout back with the results. Thanks again!
 
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Old 10-26-16, 04:53 PM
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Worked like a charm. I'd like to buy you a beer.
 
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Old 10-26-16, 06:48 PM
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Thank you. I gave up beer almost twenty years ago, first for health reasons and later the smell. I used to like the smell of beer but these days I find it nauseating.

Do you see what I mean when I stated that three-way switches are easy? The two brass terminals ALWAYS connect to the same terminals on the other switch. That leaves only two terminals, one on each switch. Power has to go in one terminal and out the other terminal. Draw it out and it is obvious every time.

The problem comes when you toss in a four-way switch where you can have three or more different switch locations. Just remember that the four-way switch(es) connect only to the "travelers", the wires between the brass terminals on the pair of three-way switches and it is only slightly more complex.
 
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Old 10-26-16, 07:25 PM
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Well thank you for taking the time to help, it is much appreciated.
 
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Old 10-26-16, 07:54 PM
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You are quite welcome, my friend.
 
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