WOW another picture. YIPPIE...Not to take anything away from the geeks core drilling. I did this a few yrs ago. I just figured out how to post pics. Yippie First let me say the owner wanted those fixtures like that. SO he gets what he wants. This is the last light to the picture below But as you can see there is a paved parking lot. Then the building. So I had a gut feeling that I could core drill the holes. Then I hoped there was 57 stone under the concrete. So I took 30ft of 3/8" thread rod drilled a hole on the end so I could tie the string to it. After the holes were drilled. I took 30ft of 3/8" thread rod and started going under the concrete with my cordless drill till the last hole. Then I tied a small string to the thread rod and pulled it back out. Once I had a small string I connected the leads to the string, then pulled the leads out. The core drilling was the PITA. I have had alot of core drilling experience in the past. So I knew what I was doing with it. It took about 6hrs to do all the holes. Some places were deeper then others, it also seemed harder concrete in some places. The fixtures are cast well lights, so there is a 25' lead on them. I added some wire to the furtherest fixture so I could make the connection on the edge of the concrete. The last picture is on the same job, but these lights were easy. I used a 4' drill bit. I really enjoyed this project. It turned out great. It was a good fun challenge. I'm proud of completing this job. It was one of those I think I can pull this off. It turned out great I think.