I only have one transformer and plugged it into an X-10 outlet in the indoor laundry room. I then ran the low voltage wire through the wall to the transformer. My transformer had a timer attached to it so I just have it set to be always on and let the X-10 wall outlet switch it on and off. With this set up you can not dim the low voltage lights though, they are either on or off. You could use the X-10 wall outlet in an outdoor weatherproof electrical box and accomplish the same thing, but again, you will not be able to dim the low volatage lights.