Running landscape lighting or irrigation under an existing walkway is always a challenge, especially if you didn’t plan for it ahead of time.
One of the most important things you can do while planning your next walkway or patio project is to consider where future access might be needed and add a wire chase. Even if you don’t think you’ll ever need to bring a pipe or wire across a walk of patio, plan for it. It’s easy and cheap and you’ll be glad you did if the need every arises.
As you can see in the above photo, the yellow lines represent wire chase locations. If any landscape lighting/irrigation projects are planned in the future there will be plenty of easy ways to get the pipe/wire around the garden space.