Typically, an electrician would install a new weatherproof outlet. It would be wired to the EasyTouch system and be able to be supplied with power by a relay that you assign Yard Lights. The 12V transformer would plug into this outlet.

There are also larger outdoor rated transformers that will allow a larger draw of current for more lights. These systems have a habit of growing.

The use of flexible conduit from the transformer box to the panel allows the wires from a relay/aux to turn them on. Remember to use a GFCI equipped breaker and attach the transformer to the bonding grid.

I never did like using a convenience GFCI outlet at the panel connected to an aux relay for low voltage lights. I prefer the convenience outlet on it's own breaker.

In my neck of the woods (NJ) where wintering is required, most people shut down the automation system and all breakers except the convenience outlet. This allows cover and step pumps to be plugged in if their isn't one near the house for this purpose. If the GFCI trips for these pumps, it's a lot more convenient to reset it in most cases if it's by the house.

Scott