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I was mounting a baseboard heater to the wall today. I was pretty sure the screws were going into studs but at some point I tripped a breaker on a nearby outlet. I was afraid that I had hit a wire so I cut into the wall near where I was drilling. The good news is that I had indeed hit the stud. It's a older house with wiring mostly from the 50's. So my question is, what else could have tripped the breaker? Could it just have been the vibration from the impact driver? Or is there something else I should be on the lookout for?

We had an electrician in at some point last year to upgrade/ground a few of our outlets. He commented at the time the wiring was getting pretty old and we should probably start looking into pulling new wire at some point. He also said to look out for any tripping breakers which could be a sign of damaged/worn wiring.

brassmookie
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  • See https://diy.stackexchange.com/a/97885/18078 for instance. Something shaking into a short-circuit condition is also possible, but not what I'd reach for first. – Ecnerwal Sep 24 '23 at 20:04
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    With the breaker off check to see how close the outlet screws are to the box and if the outlet is tight to the box. – crip659 Sep 24 '23 at 20:27
  • Um, old wiring would actually cause fewer overload trips, ones where it didn't trip but should have when slightly overloaded because the poor connection limited the current consumed by the device, keeping it under the breaker current. – dandavis Sep 24 '23 at 22:14
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    It probably just stalled the drill's motor at an unlucky point where it presented a dead short to the breaker. When working, there's many dead shorts per second, but they are under 1/60th of second and "absorbed" by the motor's inductance, but when spinning stops and the brushes are just right, you have a short since a coil is just wire between the poles, and without the dynamic effects of current going on and off, it presents just resistance... In short, nothing to do here, pretend it didn't happen and it probably won't happen again. – dandavis Sep 24 '23 at 22:16
  • I think you are referring to use with a corded drill? I was using a cordless drill, just to clarify – brassmookie Sep 25 '23 at 13:33
  • So I decided to just go ahead and retire that outlet, just to be sure. I pulled the wire and found no sign of physical damage anywhere. I did however see signs of charring inside the outlet. Not sure if the charring was from this most recent incident, but it definitely seems like the wiring inside the outlet was suspect. So my best and only guess is that the vibration from the impact driver working nearby jarred something inside the outoet? https://imgur.com/a/dKrZ1nW – brassmookie Sep 25 '23 at 16:43
  • a cordless drill negates my speculation. – dandavis Sep 25 '23 at 18:47

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If the breaker tripped, current was flowing somewhere it shouldn't. Hitting a stud is not a guarantee that you didn't hit a wire, if the wire was passing through the stud at that point and you drilled too deep.

(Note that this is one reason metal plates are sometimes put over places where wiring penetrates a stud; it help to stop that mistake from happening.)

@dandavis pointed out the other likely scenario: If the breaker that blew was the one the drill was plugged into, it's time to service the drill, replace it, and/or learn not to let it stall.

keshlam
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  • I had considered this as well but I opened the wall enough to see that there were no wires running through the stud. But it's possible that outlet is attached to the stud. – brassmookie Sep 24 '23 at 20:05