I am installing Low Voltage lights under cabinet in newly constructed kitchen island. The island was custom made by my carpenter using a custom base cabinet and custom upper cabinet – he built a base for the bottom to sit on, finished with chamfered corner posts and built 4 columns that sit on top of the counter and tie into the upper cabinets (it’s really beautiful, cherry done natural) – in my plan was to wire for the under cabinet lights, so I did all the wiring from the basement, up through the base to a box cut-out on the side of the base cabinet for a dimmer switch then wired up through the columns for the lights. Planned to mount transformer in basement so that it is accessible and join all wires in a junction box.
My wiring plan was as follows: (15 amp circuit)
14/2 from power to dimmer switch – 14/2 from switch to transformer input side (B&W) – 18/2 from output side of transformer to lights. I bought the “pucks” & transformer from Seagull and now that I am installing I read that they refer to an Electronic Low Voltage Dimmer switch on the 120v side. I already bought a regular dimmer switch but now am concerned about using that. Do I need the electronic low voltage dimmer switch? If yes, will my wiring plan still work or will this need to be modified?
Thanks in advance.
Replies
There are two kinds of low voltages transformers.
Magnetic transformers and the so-called "electronic transformers (acutally switching power supplies).
To the dimmer they are electrically different than the incandnese light bulbs.
Because of this they make ones specifically for magnetic transformers and different ones for use with electronic transformers.
However, I have seen some of the regular ones that are also marked for used with one of the other types.
If you already have one it is worth trying.
The potential problem is that you don't get good control of the light. It will flicker or not work at all until a certain point and then go full on.
To do dimming on low voltage, the transformer/converter and dimmer need to be compatible.
A regular el-cheapo dimmer attached to a regular transformer is apt to result in damage to one or the other. The dimmer may be damaged because of the high voltage spikes developed across the transformer when the dimmer switches off and on (which it does rapidly in order to dim the light). The transformer may be damaged due to overheating from the high-frequency harmonics developed in this process, or if the dimmer ends up generating some degree of DC component.
Electronic voltage converters are less likely to be damaged by a dimmer, but may not dim reliably, and still may damage the dimmer.
my electrictian told me that you shouldn't really halogen bulbs as it reduces the bulb life.
it has something to do with the operating temperature and the tungsten? not being rediposited on the filament??
maybe someone who knows what they are talking about can enlightenus :o)
That is true. Howewver, it is easily worked around.Every so often run them at full brightness. I have not seen any studies that indicate what percentage of the time that you need to so that.But you need to do it for some period of time, I am guessing maybe 0.5 - 1 hr when you do it.
This is an area of some contention. There is a theoretical effect, since the quartz shell of a halogen bulb needs to be a certain temp to keep it from darkening. But I've never seen anyone come up with figures indicating that it's a serious problem, and many people report dimming halogens without experiencing trouble.