Lights at 15 volts or less requires a pool/spa type transformer. Lights at more than 15 volts but less than 150 volts requires ground fault protection. But is it ok to use color-blending LED submersible lights that operate at 24V DC? According to NEC 680.51, a ground fault breaker is required. But if moisture gets to the conductors after the power supply, the GFCI won't trip. Any ideas?

You would have to ask this question ......

At this point, all you can do is look for the UL label and follow the instructions.

UL has a proposal to the NEC code committee on these lights. While their proposal was rejected (so far), I expect that the committee will ultimately address the issue in the 2011 NEC. However it shakes out, I suspect code language will be added to the effect of 'look for the listing and follow the instructions.'

Otherwise, as things currently stand, there is no NEC compliant way to use these lights.

FWIW, I suspect the same effects are possible with fiber optic lighting, which is currently allowed.

LED lighting products are now required to be Listed (approved) in Canada as of the 2009 Code

This would be a listing / code issue specific to pool lights, and not LED lighting in general.

There are plenty of 12V AC LED lights out there, in white and in color. No problem with these lights since they are 15 volts or less. The color-blending lights, lights that connect to a power supply and then to an MP3-type controller for programming, are the lights that I'm questioning, which are 24V DC lights.

Are these for a spa? I had some small colored LEDs and lasers to pimp my fishtank a few years ago that looked absolutely terrific at night. No UL warnings requiring GFCI that I can recall, although we did use a GFCI outlet for it.

Can you post a link to the lights you are using? Cutsheet?

The lights are for a fountain. The GFCI outlet would only be good for up to the power supply connection.
The following is a link to the manufacture. Color Kinetics provides the lamp, the power supply and the controller, and I provide the underwater light. The Color Play 3 color-blending program software is free as a download. LED technology is just getting better and better, and is prety much making fiber optic lighting, for fountains, obsolete. But these 24VDC lights are not mentioned in the NEC section 680 for any body of water (swimming pool, spa, fountain, etc).

http://www.colorkinetics.com/ls/

Are you using the C-Splash? The few of these that I've seen are usually hardwired on both the primary and secondary side of the power supply. I don't think a GFI would do anything for you since there is isolation through the power supply (It's probably a switching power supply).

It doesn't seem like there is a way to do this legally, but obviously these units are all over the US doing just fine. Have you tried calling Color Kinetics for their take. Some of their filed guys might know what has worked in the past. If all that fails, time to find a 24V DC GFI!

Yes, sometimes the C-Splash 2 series, under the RGB Intelligent Lighting Systems. Mostly, I use the iColor MR g2 lamps and put them in a bronze underwater light that accepts MR-16 low voltage lamps.

Has Color Kinetics ever given any comment on this common situation?
I like the iColor series, I use them for night lights a lot!

They say that their lights are UL Listed. Beyond that, pretty much got a politician's answer. We're pursuing 12VAC color-blending lights, and hopefully will be able to offer these lights in the next month or so....