I use X10 to control a very large landscape lighting system with 6 low voltage transformers and over 200 lighting fixtures. Each transformer has a AM466 appliance mod to apply power to the transformer. I use a MT-14 mini-timer (in conjunction with a photocell) to turn the lights on a dark and off at 11:30 PM.
Here is a write up on a system I use to control 6 low voltage lighting transformers:
Lighting Control with X-10 System
T X-10 mini timer Enclosure in utility room
SS X-10 Super Socket Duplex Electrical box
PF X-10 Power Flash “
TX 120 VAC to 9VDC transformer “
AM X-10 Appliance Module 6 units @ each lighting transformer
PC Photo Cell Right side of house next to electric meter
Starting with all units and lights off
At 5PM Timer T sends ON code to Super Socket SS set to unit code 5, no action other than power applied to Power Flash PF module.
Photo Cell PC senses darkness and closes power circuit to Tansformer TX, TX sends 9VDC to indicator lamp & PF. PF sends ON code to (6) Appliance Modules AM’s set to unit code 1. All 5 AM’s turn on and apply power to lighting transformers. All lights on.
At 9 PM, Timer T sends ON code for unit(s) 1. If photo cell has not turned on lights by this time, this will turn on all AM units and turn on all lights.
AT 10 PM, Timer T will send OFF code to unit 5, the SS unit. This will remove power from the PF unit and prevent it (and the photo cell) from controlling the lights for the rest of the night.
At 11;30 PM, Timer T will send the OFF code to unit 1 (the 5 AM units). This will turn off all lights. The circuit is now reset and ready for the next evening.
At any time the lights can be turned off or on with the mini controller in the master bedroom. Control Button #1.