I was replacing an existing switch to a wireless smart switch today. I did not turn off the breaker for that circuit (I am not electrician, only have basic knowledge about changing switch / receptacle, changed switch and receptacles before while the breaker was off) somehow I thought it's ok to not turn off the breaker this time. And it caused a spark as I was screwing the black wire down, the switch next to it has some burnt mark as well as the wall(that switch is still functional though). Then I turned that circuit off and took the wireless switch out. So my question is are all the wires still good ? If I change all the switches to a new one then everything should be good and safe ? Thanks enter image description here enter image description here enter image description here enter image description here enter image description here

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    Not sure why your question received a down vote. Making a (potentially fatal) mistake shouldn't earn that. As a newbie to electrical work, here's a tip: ALWAYS turn power of at the breaker before doing any work.
    – FreeMan
    Mar 9, 2023 at 12:23
  • And check you got the right breaker off.
    – crip659
    Mar 9, 2023 at 13:38
  • "Basic Knowledge about changing switch/receptacle" should definitely include always turning off the breaker and making sure the correct breaker is off. Not doing that can kill you.
    – Ecnerwal
    Mar 9, 2023 at 13:48
  • I hate to say it, but I get tired of the hyperbole that any shock could "kill you " . Sure, throwing a toaster into a bath tub like Bill Murry did on the movie Ground Hogs Day would be very bad! But I've been zapped many times many times, sometimes due to others negligence, sometimes due to induced current, sometimes due to my own carelessness, but I just say OUCH be more careful. That said, TRUE: If a person was well grounded, like bare feet outside and contacted a hot, it could be really bad. I don't want to minimize the warnings, just put them in perspective Mar 9, 2023 at 16:19
  • Great, you've been lucky, @GeorgeAnderson - all the folks who aren't so lucky don't get to tell tales, so all the people who tell tales about it got lucky. I've been lucky myself so far. Doesn't mean I should be careless, nor encourage being careless.
    – Ecnerwal
    Mar 9, 2023 at 17:40

1 Answer 1


You caused a short, and the system performed as it was designed.

Be sure all power is off to the box.

Replace the switch and complete any other work. (It appears the only damage was to the frame of the switch. It may be ok, but best to replace anyway. The second switch can stay )

Complete your other work in that box.

Clean your wall.

Install the cover and turn the breaker back on.

You should be good to go.

  • Thank you for your clear direction, I think this incident is " good " in a way to give me a small warning that I should definitely follow the rule to turn off the power before doing any electrical work .. ( cuz I changed lights before with live power then I thought it's ok to change switch with power on too ..) I guess after cleaning up the wall and replacing all the switches then if all switches are functioning then I should be good ? Should I have a electrician to look at the wires or even the break for that circuit in case that spark caused any damages internally? Thanks
    – Edhahaha
    Mar 9, 2023 at 17:21
  • It was a common short. If you said there was a fire in the box, then there would be something else to examine. If calling an electrician allows you to sleep better, go ahead. I suspect that there is nothing damaged with the wire or breaker.
    – RMDman
    Mar 10, 2023 at 1:09

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