How to wire Two dimmers controlling a string of recessed light?

Question

Refinishing my basement and have an open ceiling at the moment. I have hung 12 recessed lights and connected them in 3 groups (groups of 2, 6 and 4 lights) using 14/2. I then ran 14/2 from the start of each group to the entrance to the room where I intend to have 3 separate dimmer switches, one for each group. I also have the power source running to this switch location on 14/2. I have run 3 sets of 14/3 wire between from this location to another location where I intend to have a 2nd set of dimmer switches further into the room.

I have only tried hooking up one set of lights to for testing purposes and can't get both dimmers to work. Tried using a diagram that was shown on here (http://www.buildmyowncabin.com/electrical/3-way-switch-diagram-7.pdf) but it did not work. Could not even get lights to come on.
I also found a diagram that has power at one dimmer and the lights at the other but not both power and lights from the same dimmer and ran a temp power line to the 2nd dimmer but even though the likes worked from either switch the dimmers did not work. http://www.do-it-yourself-help.com/3_way_switch_wiring.html ( the diagram with 2 dimmers)

Answer 1

As @Tester101 says, with conventional dimmers, you can only have one dimmer in a circuit if the fixture (or set of fixtures) is being controlled from more than one location.

If you are switching from two locations, you also need to use 3-way switches for both the plain switches and dimmers (many dimmers are 3-way compatible).

There are specialized dimmers that work as master and slave units. These do allow dimming from multiple locations, but you need to use a set of matched units. These are also much more costly than basic 3-way dimmers.

Finally, if you are running remote switches that only connect back to the first set of switches, you need x/4 cable, not x/3. Two wires serve as travelers, one as the common return and one as neutral. While not every switch requires a neutral, code now requires it as a hedge against future active devices. If you do not need the neutral, simply cap it in the box.

Answer 2

You can only have one dimmer per group. You can put the dimmer at either location, but not both locations.

There are "companion" dimmers available from some companies, that allow you to place additional dimmers in the circuit. But you'll have to use compatible equipment, which may or may not be available at your local big box store.

Answer 3

you have 3 options:

1. smart switches. these are fancy master/slave pairs that communicate digitally. the downsides being that they are always drawing some power, they're pricey and they don't have a physical dial showing the dimmer setting.

2. 3-way dimmers. these look like normal dimmers, but when one side is turned on, it disables the other side. the downside being that if the dimmer is set low on one side, you can't turn it on or off from the other side.

3. 2 switches and 2 dimmers. if you install a spdt switch and a dimmer on one end, plus a dpdt switch and dimmer on the other end, then you can use the switches to determine which dimmer is "hot". the downsides to this plan include more wiring (which could get expensive). also, it would mean having separate switches and dimmers on each end, which takes up more space and might not look as nice or be as intuitive.

note: wiring option 3 could work as follows: provide power to the spdt switch, then connect both downstream terminals to the dpdt switch. send a wire from each downstream terminal on the dpdt switch to a dimmer such that the dimmers are never connected to both poles at once, then wire both dimmers to the light (group), and connect the light to the return wire.