The following link would be helpful Here is a link that might be useful: LED UCL continuation

What is being referred to as "Xenon" here is really incandescent bulbs. Smaller incandescent bulbs (like the type found in old-style flashlights for example) have a much lower color temperature, and as a consequence the light typically feels very orange-colored and dull. Bulb designs filled with Xenon gas help compensate for this, to some extent. I can get much more into the technical details if you want, but that is the basics of it. In general though, Xenon will still give off a lower color temperature than halogen, so if you really want a brighter whiter color of light, Xenon is probably not the best option. LED is probably the best option for undercabinet lighting, but can oftentimes be overly pricey. If color rendering is an important consideration, you might want to look into high CRI LED lighting, because under regular LED lighting colors can appear just a little grey-washed or yellowish. This is likely to be even more pricey though. Incandescent bulbs (which includes Xenon and halogen) are just not particularly well suited to undercabinet strip lighting. For one thing, when there are multiple bulbs each with a lower wattage, the color of light is confined to the very warm white color territory. Then there are always bulbs burning out that need to be replaced. There are many different options, and they all carry their own subtle advantages and trade-offs. All undercabinet lighting is kind of overpriced, in my opinion, so unless you are really looking to create a dream kitchen, you might want to consider going without it.

I've never had a client complain that their undercab lights were too bright - go 400 to 500 or higher, but look for a dimmable system so you can turn them down for a dinner party. And be careful with the brand you select. If you go with the cheap ones from Amazon, they produce a green tint to the light. A better brad like WAC has a much whiter light, a better cri, and a lower failure rate. Tresco is another brand - they offer the widest variety in selection, color, lumens, and mounting options. As you plan the system, make sure you can get to everything and replace components if needed. The transformers are the first thing to go, but the leds do have a failure rate as well.

There already is a built-in one-inch light rail integrated into the cabinets (i.e. the underside of the cabinet is about an inch deep). Designer said at the outset when I asked this question in December that we would not need additional light rails because of that integrated rail. I think the issue is really just that the electrician chose thicker LED bars (I did not see them before install). I should have specced them myself, but did not. I know that is on me. In my defense, this is a whole house project that has been going on since November, this is my first major renovation, and I am also in the middle of selling my current home. So tired! Lawrence, to answer your other questions. 2. Hard wired. 3. There are three separate banks of UCLs on separate switches in different areas of the kitchen. The UCLs within each bank are linked together. 4. As currently installed there are wall switches AND switches on the lights themselves. No dimmer. 5. Countertop is honed 6. I am not sure of the light temperature. I think they said around 2800K.