I'm installing walk-way lights(110) and need to travel under a walk-way. any suggestions on "drilling" under the slab, running underground romex and not undermine the walkway?:)
romex for burial?
use low voltage landscaping lights and cable designed for burial. much easier. you plug the transformer in a gfci outlet outside with a bubble or in use cover. call for locater for wires and services before you dig. you can even find post lights made for low voltage and is still diy friendly. when you start getting into house voltage outside you are getting into a higher safety and danger area and a lot of special rules.
there is a 6' drill bit you can get that is flexible that you can use to make a sideways bore under sidewalk cable tv people do it all the time. trick is to dig out both sides of the walk and do your drilling below the stone base under the walk. if your soil is loamy or sandy you might be able to bore out a path with a pressure washer wand or even a hose with a piece of pipe screwed to the end of it that you cut the other end on angle as a stiff boring probe.
you can set up with a solar sensor or with a combo power supply and timer. you can remove the timer pins and put in a remote control receiver if you want the lights on and off by your control.
It depends on what you have under the walkway but I had to get an irrigation pipe under both a sidewalk and a 20ft wide drive way when I lived in GA. Granted, we had sandy soil with few rocks but you might try it too.
I just bought a piece of 1-1/2" PVC and pushed my garden hose into it so that the nozzle just came even with the end of the PVC. I had to dig out a small trench on either side of the driveway, about 3-4ft so I could get the tip of the PVC down under the driveway slab. It was nice because I had a conduit that I could shove a smaller PVC pipe though with no effort.
Turn on the hose and push both the hose and the PVC and the water will help jet the PVC across. Be very careful not to push your hose past the end of the PVC or it'll get stuck and then you'll have to get it back out. Not so easy.
If this fails for you, start looking for the 6ft drill that was already suggested.