A bit confused by existing 3-way dimmer switch

[ellesshoo]

There is a 3-way circuit dimmer switch that has me second guessing enough that I'd like to run it past this forum. The switches that are installed are these:

Instruction Manual: http://www.cooperindustries.com/content/dam/public/wiringdevices/products/documents/instruction_sheets/600cy_pt.pdf

Spec Sheet: http://www.cooperindustries.com/content/dam/public/wiringdevices/products/documents/spec_sheets/aspire_smart_dimmers_spsh_4_10_anp.pdf

 

I'm struggling to map the wires from these dimmers to the wires on a pair of SwitchLinc dimmers I want to install in their place. Below is the image from the above instructions with the existing wire colors labeled:

 

Any help would be much appreciated.

[apostolakisl]

This is the jist of it.

 

1) There are 2 wires that are called travelers, they connect the two boxes together. The wires may be one continuous run or they may be spliced at the light fixture (in which case the colors won't necessarily be the same)

 

2) The one box has a 3rd wire which goes to the load (the light fixture)

 

3) The other box has a hot (120vac all the time)

 

4) Lastly you have a neutral which isn't connected to a normal 3 way switch and in older homes may not be present (which makes using Insteon much harder).

 

Your goals

 

1) Have neutrals at both boxes. Hopefully already there tucked in the back of both boxes. If one box has a neutral and the other does not, you can use one of the 2 travelers to carry neutral over to the other box.

 

2) Have hot at both boxes. This is not going to be the case naturally. You will use one of your traveler wires to bring hot from the one box to the other.

 

3) One box has the load, this is fine as is.

 

According to your picture of your old swithces.

 

The master:

 

1) Has a blue and red wire coming out of it. These connect to your travelers. Label them as such.

2) Has a black wire. This is connected to your hot, label it as such

 

The Remote:

1) Has 2 blue wires, one is connected to only one wire. This is one of your 2 travelers. Label it.

2) The other blue wire has 2 wires connected. One is a traveler and the other goes to the load. You need to figure out which is which. To figure out which is which, the wire color might do the trick by matching up with the color at the other box, but not necessarily.

 

Figure it out:

1) Turn off power.

2) Unhook all of your wires (you already have labeled the ones you know)

3) Splice together the 2 travelers at the Master box.

4) Put your ohm meter onto the known traveler at the Remote box, and then touch the other lead to each of the 2 unknowns. The wire with 0 ohms is the traveler and the one with infinite is the wire to the load. Label them.

 

Install Insteon

1) With power still off.

2) At the master box,

- splice Insteon black, hot, and one traveler together

- Splice Insteon white to the neutral

- Splice ground to ground

- Cap the Insteon load (red) wire

- Cap the unused traveler

3) At the Remote box

- Splice the traveler wire that is now hot, to Insteon hot (if you don't know which is which, just pick one.

- Cap the other traveler

- Splice the Insteon load (red) to the house load

- Splice ground to ground

- Splice Insteon white to house neutral.

4) Turn power on. If the switch at the remote location does not turn on its led's you guessed wrong on which traveler. If it lights up, you got it right.

- If you guessed wrong. Turn off the power, and at the remote box, splice the other traveler wire to the Insteon hot and cap the unused wire.

5) Turn power on. Now it should work. If it doesn't, you messed something up and you need to start over.

[oberkc]

It is not obvious from me, based on your post, that you have confirmed existing wiring matches the instructions. Does it?

 

It is important to note that the instructions are based on one way to wire a three-way. There are other ways, also. It is more important to understand how your house is wired, so be sure to confirm actual wiring rather than instructions.

[ellesshoo]

Figured it out. All it took was going to work then looking at it with fresh eyes when I got back home. I was caught up with the fact that the existing switches had only 1 traveler wire, turns out those switches are pretty fancy (I didn't buy/install them). They are almost as expensive as the switchlincs. Anyway, appreciate the willingness to help.

[ellesshoo]

1 more thing, I'm pretty dumbfounded how the old switches kept their LEDs on w/out connection to neutral. Any ideas? Not important, just curious.

[Brian H]

Some dimmer switches without a Neutral. Steal their operating power through the load and it had to be incandescent type loads. Your old switches probably got power through the load and where able to keep their LED indicators On.

That is why the new Insteon two wire dimmer can't be used on any loads that are not incandescent.

[apostolakisl]

Figured it out. All it took was going to work then looking at it with fresh eyes when I got back home. I was caught up with the fact that the existing switches had only 1 traveler wire, turns out those switches are pretty fancy (I didn't buy/install them). They are almost as expensive as the switchlincs. Anyway, appreciate the willingness to help.

 

According to the diagram above, the switches are using both of the traveler wires. It's just not alternating the power from one to the other as in a "dumb" 3-way. I assume the one traveler is functioning as a communication wire and the other traveler is carrying the load.

 

1 more thing, I'm pretty dumbfounded how the old switches kept their LEDs on w/out connection to neutral. Any ideas? Not important, just curious.

 

It must be as oberck said, since neither the master nor remote are connected to neutral. It would work to run to ground, but that would certainly not be UL allowed.

[oberkc]

It must be as oberck said, since neither the master nor remote are connected to neutral. It would work to run to ground, but that would certainly not be UL allowed.

 

Actually, I think it was Brian H who offered that explanation, but I certainly agree with it.

 

The other point I wanted to make was that using ground as a neutral would not just be a violation of the UL certification basis, but a violation of the NEC (and almost certainly of any local building code).