I want to drive five (5) 12V (35W max per) ceiling fixtures with a transformer mounted to the exposed joists in the floor below. Thus, the xformer is exposed and can breathe. All five fixtures are on the same switch.
I can locate the xformer so the max length of the home run 12v feed (each will be fed by a home run) is 16 feet. Sound doable? Size me the xformer and the wire.
In another area, I will have in close proximity, three (3) 12V (35W max per) fixtures, but now two will be on one switch and one on another switch.
Can I drive these with one xformer? Or must I have two?
Replies
The first transformer you mention needs to be rated for 5x35 watts, or 175 W. If you want to buy a little extra capacity, it won't cost you much. You'll find that most devices of that size are not really transformers, but rather switching power supplies. Each lamp is drawing 3A; 14 ga will work just fine.
In the second case, you can run both lights from one transformer if your switches are on the 12 volt side. If your switches are on the 120 volts side, you'll need two switches.