Why every household needs a detection device
22/7/2026
Translation: Elicia Payne
Pictures: Ann-Kathrin Schäfer
If you drill into a wall and hit a wire, in the worst-case scenario, you risk causing a short circuit or a fire. A small, clever device is all you need to prevent this from happening.
For a long time, I naively drilled holes in walls. My only concerns were when the plaster on a wall in an older building was crumbling or when the concrete wall of a new building was too hard to work with. I had either ignored the thought that there were electrical and water lines running behind, or dismissed them out of false hope: why on earth would there be a line running right where I wanted to mount the shelf?
Looking back, I think it’s crazy – even downright reckless – how my past self would carelessly drill into walls. It wasn’t until I witnessed a renovation firsthand that I realised just how many wires run behind the walls.
For obvious reasons, you don’t want to drill into power lines – or water pipes, for that matter. In most cases, modern electrical systems prevent fires by using circuit breakers. In older buildings, that isn’t necessarily the case. Either way, a damaged line that needs to be repaired by a professional is not something you want.
It’s easy for me to remember not to drill near plug sockets and light switches. What’s not visible from the outside, for example, is where the wire for the ceiling light runs behind the neatly plastered walls. If you have an installation plan, you might be in luck. However, I’ve noticed first-hand how installations sometimes deviate from the plan.
Safety first
My carefree drilling days are over. Even though I’d like to point out I never actually hit a wire, that’s only because the probability of missing the wires is significantly greater than that of hitting them. But now I’ve found a solution that seems reliable to me: a small detection device. Maybe you already have one – in that case, I applaud you. If not, and you’re planning to drill in your living room shelf or finally hang the curtain rods in your bedroom, then I highly recommend this tool.
I’ve never drilled with such confidence before.
I chose the Truvo from Bosch – a mid-range model that costs around 40 francs. The Community rates it 4.3 stars. It’s simple to use: just guide the tool along the spot on the wall where you want to drill. A traffic-light system tells you whether there’s anything hidden beneath the surface. Green means you’re clear, yellow warns of nearby metal, and red means «Do not drill here under any circumstances!» You’ll also hear an annoying, warning beep. To locate metal and electrical currents as reliably as possible, I run the device over the same area several times.
Has it’s limits
This device can’t help me when it comes to precision work. For example, I wanted to hang the curtain rod right next to the ceiling socket so that it’s at the same height. But the Truvo flashed and beeped like crazy, understandably so.
Even to a layperson like me, it’s obvious that the corresponding power cable must run through the wall here. What I can’t get my head around is why the device continues to beep. It makes me doubt the accuracy of detection. And makes it difficult to find a suitable drilling location near a powerline.
In the reviews for another Truvo model, I read that a more professional device might provide more accurate measurements. chribi2805 for example, writes: «More expensive models have a hole that allows you to mark the drilling point precisely». Maybe that’s the solution for cases like this, where precision is key? I’ll have to look into that. Until then, the Bosch Truvo works perfectly for me in giving me a rough idea of where wires are hidden behind the wall – and where the path’s clear.
AnonymousWasTaken sums it up perfectly with two unbeatable arguments that apply to every «electricity hunter» on the planet: «Don’t drill into power lines and cause an explosion» and « I want to stay alive.» What more could you ask for?
Do you agree that every household should have a detection device? Or do you think it’s a waste of money and resources? Let us know in the comments.
Header image: Ann-Kathrin Schäfer
Ann-Kathrin Schäfer
Editor freelance
simon.balissat@digitecgalaxus.chI'm really a journalist, but in recent years I've also been working more and more as a pound cake baker, family dog trainer and expert on diggers. My heart melts when I see my children laugh with tears of joy as they fall asleep blissfully next to each other in the evening. They give me inspiration to write every day - they've also shown me the difference between a wheel loader, an asphalt paver and a bulldozer.
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