If you're already wired for AC, the only way the env lights bars can be used is by connecting individual 24V DC power bricks under the cabinet to the light bars and to the AC outlets. - AC -> power brick -> light bar.

If you want a clean look, you need to do the wiring as shown on the LED DIY UCL thread.

I'm going to apologize in advance...I'm just totally confused!

So, what was just put in my wall are 120V wires - there's no outlets, we're just in the insulation/finish framing stage - it is to these wires that he would connect the LEC ucl system....from my perspective, the Env Lights driver uses AC power and converts to DC, yes/no? He claims he would prefer to use AC power with the led ucls, rather than use DC like the env lights. Because I feel like something is not adding up, I asked to see what the product is that he is suggesting - he told me to look at Elite LED (link below).

I've googled the Elite product and I see that they have an option of using "Dimmable Compact LED AC 120V magnetic drivers" but I'm not sure that is the difference because the Env Lts 48W 24V driver says that it is 120V AC too...am I missing something here?

Also, any insight as to whether the Env Lts will be able to function with a Clipsal system? (http://www.clipsal.com.au/homeowner/home )

Here is a link that might be useful: Elite LEDs

"So, what was just put in my wall are 120V wires - there's no outlets..."

The wires do not care if they are carrying AC or DC.

One problem that crops up with under-cabinet lights is that concealed wiring must meet the electrical code and be an 'approved method.'

That normally means the same kind of cables and wiring as used for 120 V wiring.

A larger DC system might have a transformer (or electronic power supply) located in an out of the way spot and use wiring concealed in the walls to reach the lights.

Using standard romex wiring for low voltage wiring will cause confusion later since people have been conditioned to treat romex wiring as line voltage wiring.

Low voltage wiring is a separate category

For example
Doorbells are wired from the bell to the button using low voltage wiring, not romex.

The Elite LED solution from the description is identical to those sold by environmentallights, nora lighting, photonier, superbrightleds, ...

The only way to use these lights with undercabinet AC wiring is to wire them as I described in my earlier post
AC -> power supply (driver/ transformer)-> light bar

"Using standard romex wiring for low voltage wiring will cause confusion later since people have been conditioned to treat romex wiring as line voltage wiring.

Low voltage wiring is a separate category

For example
Doorbells are wired from the bell to the button using low voltage wiring, not romex. "

You do know that doorbell wiring is VERY power limited.

Concealed LV wiring for high power applications (above about 20-40 V-A) reacquires the use of approved wiring methods like NM cable (and often in painfully large sizes for voltage drop).

While a 20 W 120 V bulb pulls only 0.17 amps, a 12 V 20 W bulb pulls 1.7 amps, and the lower voltage (higher current) is VERY susceptible to voltage drop.

Dropping a 1 V or 2 V on a 120 v circuit is less than 2%.

Drop 1 V on a 12 V circuit and you are down over 8%.

Yes I do know that.

The wire gauge depends on the amount of current that is anticipated to be supplied. For individual LED bars, the current draw is low, but the correct wiring gauge will be determined by the the expected load for each zone.

The env lights 12" bar has a power draw of ~ 3.3W. With an operating voltage of 24V, the current draw for 6' is still under 1A.