Seems I have messed up the wiring my the 3-ways

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  #1  
Old 01-02-12, 07:33 PM
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Seems I have messed up the wiring my the 3-ways

Let me explain it in details

Facts:

(1) There are three 3-way switches controlling the staircase lights.

(2) Each switch has 3 wires.

Before:

Switch A and B works perfectly. either one can turn on /off the light. Switch C is considered as irrelevant. Lights will not be affected, no matter it is on or off.

It is OK to me, as switch C is never used anyway.


Now:

ALL the switches need to be on in order to turn on the light. Either one off willl not on the light.

I tried to use a screwdriver with a light bulb at the end of it, to test the connection.

If switch A and B both on. Switch C on:

pen bulb is on when it it touch on connection point C2, C3,
pen bulb is off when it is touch on connection point C1

If switch A and B both on. Switch C off:

pen bulb is on when it it touch on connection point C3,
pen bulb is off when it is touch on connection point C1, C2

If switch A is on, B if off:

pen bulb is off when it touch on connection point C1, C2, C3, no matter Switch C is on/off itself

Now,

If switch A and C both on. Switch B on:

pen bulb is on when it it touch on connection point B1, B2, B3,
(I notice that the pen bulb is dim when touch B1)


If switch A and C both on. Switch B off:

pen bulb is on when it it touch on connection point B3
pen bulb is off when it it touch on connection point B1, B2



N.B.
The wiring in switch C has never been changed.
All the wires are red color (the ground wire is ignore here.)
There are 3 wires in each switch box. All switch are 3-way 9not 4-way)


Could you please guide me how to fix it? Do i need to make more testing by "screwdriver with bulb" on different situation?
Read more: http://www.doityourself.com/forum/el...#ixzz1iMb2kd9x
 

Last edited by ray2047; 01-02-12 at 09:52 PM. Reason: Should have been one post.
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  #2  
Old 01-02-12, 09:45 PM
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(1) There are three 3-way switches controlling the staircase lights.

(2) Each switch has 3 wires.
Only two switches can be three ways. the other switch has to be a four way with four wires connected to it.

With 3-ways the important wire is the common, the odd colored (usually dark colored) screw. Power goes in at the common of one 3-way switch and out to the light at the common of the other 3-way switch. It doesn't matter which traveler goes to which brass colored screw.

On the 4-way though the travelers are the key. The travelers from one 3-way go to the input side and the travelers from the other 3-way go to the output of the 4-way. The commons are just connected together. If not marked input output you will probably have one set of dark screws and one set of brass screws.

A pen tester is too inaccurate to give a usable reading even if your tests are meaningful. You will need a multimeter or test light to find which cable is the power in. There are several ways it can be wired depending on if the power comes in at a switch or the light.
 
  #3  
Old 01-02-12, 11:02 PM
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Thanks Ray,

(1) First of all, all screw are the same color in my house. I assume the middle screw is the "common" / "input" one



(2) Seondly, you are right, I open up switch B and find that there is a 4th wire hidden deep inside the box. I never seen it before

Could I assume this 4th one be ignored?

Before I make any changes days ago. Switch A and B can work perfectly as a pair of 3-way. (They are always a 3-way switch, same as the one in the picture above)
Switch C was no use (It cannot affect the light no matter on or off.)

I would believe, the electrician intend to use 3-way for A and B. Because they know switch C is really remote to the user and not intend to use anyway.

Is it possible to just connect the wires in A and B correctly. So as to make they work as a normal pair of 3-way switch?


Also, I am curious how they could make Switch C couldn't control the lights, without touching the wires in C at all. (C is inaccessible to anyone without my permission)

I am happy to leave C alone (i.e. its on/off not affecting the light)


If switch A and B both on. Switch C on:

pen bulb is on when it it touch on connection point C2, C3,
pen bulb is off when it is touch on connection point C1
And one more thing, it seem notreasonble to have such result.



for a 3-way switch, no matter how it is connect, no matter it is on or off, it should always be the case that the bulb in tester will be ON for two screw, shouldn't it?
 

Last edited by freshman; 01-02-12 at 11:54 PM.
  #4  
Old 01-03-12, 05:55 AM
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Thanks for the picture. That caused me to check your location because I have never seen a device like that. This is primarily a North American board. While three way principals are the same wiring methods and devices are so different I doubt anyone here can help. Sorry.
 
  #5  
Old 01-03-12, 10:35 AM
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Switch may be just making continuity. If you do not want it, I would remove the 3 wires from the switch, making note of where they are connected. Check an see if your light still works with
A & B. If it does, just cover the ends of the wires and put a blank cover back. If the light does not come on then you have broken the continuity of the ckt. Check for voltage across all of the 3 wires. If no voltage, then connect any two together and check you light again. If it is off, reconnect the other conductors until the light is working.
 
  #6  
Old 01-03-12, 05:31 PM
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Please note the OP is in Japan.
 
  #7  
Old 01-06-12, 07:55 AM
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Thanks for your help.

I can now fix it up. (pity that it is largely based on trial and error.)

i have take a picture of the correct connection. (just in case)
 
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