Drill From 1st Floor To Second Floor

Question

I am wiring my home with Cat6 and I have my 1st floor wired thanks to tips used from users on this forum! Well now, I need to go between floors! I have found a location that is a straight shot up, but since I will not be able to see between the floors, is there EVER electrical wiring run between floors (or plumbing) that I could hit? And if so, how do I make sure to avoid this?

Also, I was going to add some Blue Carlon Conduit for ease of replacement in the future, however I am not sure how to handle this...The issue I see is that the inside of the tubing is 3/4 inch, and the whole tubing in itself is roughly 1 inch. Which would mean I would need to cut a 1 inch whole from the crawlspace to the 1st floor, then from the 1st floor to the 2nd floor, then the 2nd floor to the attic. Again, I have found a straight shot, but how do I ensure there is nothing electrical/plumbing or any other obstacle that would be disastrous to hit in the path?

EDIT
Sorry that my ? is not clear. I am fine with cutting the drywall from floor to cieling to ensure there is nothing behind it. My question is, how do I ensure that between 1st floor and 2nd floor where I drill up, there is no electrical wiring or water pipe(s) or anything else that could be hazardous to drill through? .g

Answer 1

Lots of stuff can lie between the floors - electrical wiring, telephone, doorbell, coax, speaker or other low voltage wiring, plumbing for potable water & waste (including vents), plumbing for heating systems, gas lines, HVAC ducts. And probably more that I'm not thinking of.

That's why you need to cut a small hole in the drywall with something that doesn't penetrate far into the cavity to see what's going on. There's a small risk that you could damage something laying on the drywall, but it's unlikely and shouldn't be power, plumbing or gas.

I'd probably drill a hole just big enough for a small inspection camera - you can get some cheap units that plug into a cell phone that would likely be good enough for this. Use a stud finder so you don't hit a joist. If you pick a bad spot, you can fix the hole with a dab of spackle.

Answer 2

If you are unsure of what may or may not be inside the wall it is necessary to open up small inspection holes in the wall. Holes 4" x 4" are typically used for this purpose. If your wall surfaces are drywall or sheet rock that is a good thing because it is relatively easy to patch up these holes, particularly if you keep the cut out piece to be used for the patch.

Sometimes when running conduit or wires from floor to floor it is necessary to open up slightly larger holes (maybe 4" x 6") near the floor and the ceiling to gain access for drilling the necessary holes and shoving the conduit/wires through.

There are numerous questions here that address the process for patching these access and inspection holes.