You should always trip the breaker
#11
  Re: (...)
I had some can lights not working in the basement, and there was power in the feed. So, with the switch off I removed the wire nuts, tested for current between the black and white wires, all's good. Took my finger and started feeling the connection between the lights and the Romex thinking one needed just a wiggle to re connect. Funny, the neutral gave me a little tingle (let me mention I'm up on a wooden ladder; guess I wasn't grounded very well. Got my meter again, and tested neutral to ground and got 120V. (???). Went back over to the light switch and pulled the plate. The PO (affectionately known as Mr. Numbnutz on good days) had wired the switch to break the neutral instead of the hot. As i was thinking this through, the tingling made sense (that's the question here) as there was a live hot to the fixture???? PS I did change the switch to break the hot leg, and also have have the lights working now. Just glad I wasn't knocked on my butt.
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
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#12
  Re: You should always trip the breaker by fredhargis (I had some can light...)
Light switches with lights inside them can also pass some small current when off (which is what lights the little indicator), so even when off, it's on. Take the bulb(s) out and no light. Which means the neutral is hot and not at zero volts when disconnected (since it's not being held to zero volts relative to earth), even with the light switch off. So yes, turn off the breaker. And check that there actually is no power before touching things.

And don't take anyone else's word for it. When I worked in demolition, a very long time ago, we started on an industrial pump building that supposedly had it's power cut at the main building. I was on a track loader, and another guy was on an excavator. When he got to the wall with the panel, sparks started shooting out. 480V 3-phase was still live in one panel.* Either one of us could have been killed. So much for facilities folks telling us the power was cut.

*Just one reason of many why the NEC only allows one feeder to an outbuilding, as a general rule.
Tom

“This place smells like that odd combo of flop sweat, hopelessness, aaaand feet.”







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#13
  Re: You should always trip the breaker by fredhargis (I had some can light...)
What does PO mean?
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#14
  Re: Re: You should always trip the breaker by Herb G (What does PO mean?...)
previous owner.....sorry.
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
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#15
  Re: You should always trip the breaker by fredhargis (I had some can light...)
Whats funky is that with some higher voltages in contact you can't let go.
Paul from the beautiful mid-coast of Maine (USA)
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#16
  Re: You should always trip the breaker by fredhargis (I had some can light...)
Yeah, I got caught by that one a while ago. I was re-installing a garage heater/convector installed by a PO. I cut cut the Romex powering the fan without tripping the breaker. Got a nice arc and a divot out of the wire cutter. In retrospect it was pretty dumb to think that the PO would wire the switch correctly, as badly as he hacked everything else he touched.

Trip the breaker.
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#17
  Re: Re: You should always trip the breaker by A Squared (Yeah, I got caught b...)
A Squared said:


it was pretty dumb to think that the PO would wire the switch correctly, as badly as he hacked everything else he touched.

Trip the breaker.




My world exactly! I referred to PO as Mr. Numbnutz, but most of the time what I call him is a lot less civil. My person spent his life in construction; seems like he would have had at least a little sense.
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
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#18
  Re: Re: You should always trip the breaker by fredhargis ([blockquote]A Square...)
Get yourself a non contact voltage detector:

http://www.amazon.com/Klein-Tools-NCVT-2...oltage+detector


Klein or Greenlee or another reputable outfit.


Put it in your electrical service tools and use it. One of the best things I ever got.
Use it ALL the time. Would not be without it.
Mark Singleton

Bene vivendo est optimum vindictae
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#19
  Re: Re: You should always trip the breaker by MarkSingleton (Get yourself a non c...)
MarkSingleton said:


Get yourself a non contact voltage detector:

http://www.amazon.com/Klein-Tools-NCVT-2...oltage+detector


Klein or Greenlee or another reputable outfit.


Put it in your electrical service tools and use it. One of the best things I ever got.
Use it ALL the time. Would not be without it.




+1 on this
I use mine to double check every circuit I'm working on.
chris
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#20
  Re: Re: You should always trip the breaker by doobes ([blockquote]MarkSing...)
I have one. But if I check with a meter and find no voltage, I don't use it to double check the power.
I started with absolutely nothing. Now, thanks to years of hard work, careful planning, and perseverance, I find I still have most of it left.
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