It takes 2 minutes to fix a hole with filler paste. You can also find a discrete place to put it, like the opposite side of the wall, under the threshold, behind a closet, using existing holes for wiring.

Drilling gently through wood or gypsum, you will notice immediately that you got through the sheet, before you can even hit a pipe or anything else behind. Then use that hole for the endoscopy to map out the beams and sensitives behind.

As i have not done this, my concern was drilling into wiring. I have a multi story house and i figured there could be writing that drops down through the walls that are not directly aligned with any switch.

Am i being overly paranoid ?

It’s good to be cautious. Drill slowly, with the assumption that you are going to hit something.

If you assume that your walls are 12mm gypsum and you stop drilling after 12mm, nothing can happen, start slowly, use the smallest drill, tape your drill as stop reference. If you hit open air you will immediately notice that you’re through. If you don’t hit open air after 12mm, stop, think, reconsider. Maybe you have thicker walls, maybe you hit a beam, etc.

The difference between gypsum, wood and steel is so big you will feel the difference if you go slowly. With gypsum you can almost push a needle through with hand force, from there make the hole bigger. Concrete walls are a totally different story.

Don’t have the intuition for how it feels once you get out on the other end of a plank yet? Dry run using a scrap piece of wood, where you can see the back side. Pin some scrap wire on the back and see what happens when the drill hits a worst case scenario. In a real wall the wire would be assembled before the final panel so there you’d have even more spacing. Logically, the wire will be behind the sheet, not embedded inside it.

I want to let you know that this advice worked a treat. Thank you for giving me clear direction and the confidence to do it.

> Am i being overly paranoid ?

This is a good quality when drilling holes in the walls. Fortunately, technology to the rescue! Plenty of metal/stud/voltage detectors on your favorite hardware or online store.

Not really. It's not massively likely, but if you do manage to drill into one fixing it is pretty costly. And that's not taking into account the risk of electrocution

Check out the Gosforth Handyman on how to avoid pipes and cables: https://www.youtube.com/watch?v=DeTXAPYzqpY

(Note that the rules he describes on where cables should be are from UK regulations - other jurisdictions will have different rules).

you have tons of holes in your walls already you can probably use one of those. Power outlets, light switches, etc.