I finally got all the parts together for my lighting design, and I spent several days installing everything. I am reporting a very successful outcome thus far, as you can see by the image. While I can switch both circuits on and off, I am waiting on the Lutron dimmers to enhance the control over the system. I'll briefly describe the system design, along with the parts I selected.
I chose a low voltage cable lighting system, to enhance the achitecture of the space, and because it made sense for a SIPs (structural insulated panels) house. The wiring is exterior, and the five cable runs give me access to every area of the open space as shown in this sketch:
You can see a section view on top, showing the cable running from one wall, through the beam, and to the other wall. The runns start at a wall mounted junction box. Each box is hardwired, and there is a low voltage electronic Hatch transformer in each that steps the voltage down from 120v to 12v. Each transformer is capable of handling a maximum of 60w. THe plan view shows the two circuit, five run layout, with lamp locations sketched in.
The lamps are Lighting Science Definity MR16 HI-Output LED lamps. This is an amaziing product. At only 8 watts, it puts out an astonishing 800 lumens, or the equivalent to a 50 watt MR16. The color temp is 2700 CCT (color temperature), and the CRI is almost 85. Needless to say, they are quite beautiful! And dimmable.
The Hatch electronic transformer was selected from the available lamp transformer compatibility chart. There were not many options available for 120 watt input voltage! You can find transformer compatibility charts for many LED products, as well as dimmers. I installed five of these, one in each wall junction box at the beginning of each run.
I contacted Lutron for dimmer recommendations, and they suggested the DVELV-303P. This is an electronic dimmer, 3-way (DVELV-300P is single pole). I tried a cheaper, similar product already, but I did get a sighti flicker, so I returned them! On to the Lutron...I'll report on the success of these when I get them.