Hello,
In preparation for a "put up lots of shelves" project, I've suddenly become anxious about drilling into electrical wires in the wall. Even if I buy a blue Bosch detector for 1000 kronor (GMS 120), it only detects electricity 5cm into the wall, and I was planning to drill 6 or 7 cm to use sturdy screws in the "slaggbetong" wall from 1910. Moreover, people here on the forum say that you can't trust the detectors anyway because they measure all sorts of ways.
So what do I risk if I accidentally drill into an active electrical wire? Can it cause short circuits and lead to fire or other dangers in our apartment building?
(I find it hard to believe there would be water pipes in the walls in question, so the risk of water damage is probably small.)
In preparation for a "put up lots of shelves" project, I've suddenly become anxious about drilling into electrical wires in the wall. Even if I buy a blue Bosch detector for 1000 kronor (GMS 120), it only detects electricity 5cm into the wall, and I was planning to drill 6 or 7 cm to use sturdy screws in the "slaggbetong" wall from 1910. Moreover, people here on the forum say that you can't trust the detectors anyway because they measure all sorts of ways.
So what do I risk if I accidentally drill into an active electrical wire? Can it cause short circuits and lead to fire or other dangers in our apartment building?
(I find it hard to believe there would be water pipes in the walls in question, so the risk of water damage is probably small.)
If you drill into an electrical wire, a short circuit will most likely occur and the fuse will blow. Then you have a big job replacing the damaged cable. There is also a risk of personal injury from electric shock if things go badly. Fire is probably less of a risk, but it is highly inappropriate to drill into an electrical wire. There is often logic in how the pipes are arranged in the wall that can be understood. Especially if you have a meter. It is rare for the pipes to run in the middle of a wall where there are no outlets, for example.
Was at a daycare troubleshooting once, and it wasn't possible to turn off the lights in an office!
After quite a bit of troubleshooting without finding the fault, I asked the staff when the issue started, they replied that it had been that way since the summer when the craftsmen installed a new shelving system.
I then checked their mounts and saw a suspicious spot and sure enough, they had managed to hit both wires down to a switch and short-circuited them, resulting in the light always being on (a minor problem in the context).
What was worse was that there was electricity throughout the metal shelving system that was mounted above the desk...
So, yes, it can go badly!
Apparently, the municipality's own electricians had been there but hadn't found the fault and just left...
Best regards/Jonas
After quite a bit of troubleshooting without finding the fault, I asked the staff when the issue started, they replied that it had been that way since the summer when the craftsmen installed a new shelving system.
I then checked their mounts and saw a suspicious spot and sure enough, they had managed to hit both wires down to a switch and short-circuited them, resulting in the light always being on (a minor problem in the context).
What was worse was that there was electricity throughout the metal shelving system that was mounted above the desk...
So, yes, it can go badly!
Apparently, the municipality's own electricians had been there but hadn't found the fault and just left...
Best regards/Jonas
It is admittedly always unfortunate if you accidentally drill into a cable. It leads to quite a bit of hassle and costs to fix. IF you accidentally drill into an electric cable, there is a certain risk that the drill will become live. But usually, the machine is insulated where you hold it, so the risk of getting a shock is quite low, but possible.
Fire is not a risk in a wall of non-flammable material. There is no risk that the damage could cause dangerous heat development other than right where you damaged the cable, and there the wall was made of slag material.
A friend actually experienced a fire in a wooden wall when he was drilling. The power went out, and smoke started billowing from the drill hole. He brought in the garden hose and sprayed into the drill hole. Later, when he opened the wall to fix the damage, there was an area around the cable where it had charred.
If it had been me, I would probably have called the fire department AND at the same time extinguished it myself as best I could.
Fire is not a risk in a wall of non-flammable material. There is no risk that the damage could cause dangerous heat development other than right where you damaged the cable, and there the wall was made of slag material.
A friend actually experienced a fire in a wooden wall when he was drilling. The power went out, and smoke started billowing from the drill hole. He brought in the garden hose and sprayed into the drill hole. Later, when he opened the wall to fix the damage, there was an area around the cable where it had charred.
If it had been me, I would probably have called the fire department AND at the same time extinguished it myself as best I could.
Isn't that advice hardly something to rely on in general? I don't know how electrical installations were done at that time, and hopefully, not much of the original remains, but it is very likely supplemented at a later stage.anaitis said:
Hobby electrician
· Värmland, Molkom
· 26 845 posts
I find it doubtful that there would be embedded wires in a wall from 1910, but take that as input into the probability of your risk analysis If there were an embedded cable, it would likely be a slightly larger wire, a main line. It could be in good condition where it has been protected in the wall.
If there were an embedded cable, it would likely be a slightly larger wire, a main line. It could be in good condition where it has been protected in the wall.With the risk of hijacking the thread. Was it only surface-mounted installations at that time? I've seen recessed wiring even in houses that were built without electricity, so there must have been instances where pipes were routed into existing walls.