I had an issue the other day with zenon under cabinet lights (UCL). Each UCL has a high and a low brightness setting. When the lights were on the low setting the intercom transformer (that's on the same circuit) would buzzzzzzz like crazy. On high there was no noise. These were 12v lights.
I don't have an answer to your question as I never figured out what the issue with my situation was, but my guess would be it has something to do with the transformers, as computers use 12v also.
Edit: If anyone ever goes to add power for an intercom system, pull a dedicated line to it if at all possible. This way you won't have any buzzing issues. Some equiptment states in the literature that a dedicated circuit is required.....my guess would be because of the buzzing associated with some lighting systems.
Last edited by gilbequick; 02-03-2008 at 07:08 PM.