Shock with switch off..

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Replacing a light fixture Saturday and received a shock with the switch turned off. After taking down the old fixture I had two white wires (twisted together) and one black. Brushed the bare white pair and got a shock (may have been touching the ground at the time but i'm not sure). How is this possible? The wiring in the house is original (cira 1984) except for a few fixture replacements.
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James wrote:

Never trust someone else's wiring. In the last week we have had at least one person try and tell us it makes no difference how you wire a light (hot vs. neutral) because the light will work either way. It's done.
I will add that switching the switch off and hoping the line is dead at the controlled lighting fixture is very dangerous even if no Buba did the wiring. The power may come into the fixture box and then out to the switch so there is always a live feed to the fixture box.
I remember one time I was working on an overhead fixture and while pulling it down I was showered with sparks. I had turned on the light and then removed the fuse (this was a long time ago) checking that the light was out before starting on the job. As it turns out, the bulb burned out when I was removing what I thought was the correct fuse.
Be save, assume every wire is hot.
Glad you survived.
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math
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neutral is switched instead of the hot, or ... the other possibilities are too hard to describe in words. First, NEVER ass-u-me a ckt is dead because the switch is off: Power has to get TO the switch somehow, and that might be via the light fixture. Also, ALWAYS pull the fuse or breaker before you touch ANY wiring. Then, BEFORE you touch any wires, PROVE that they are dead before THEY prove you are dead! The best way is to test the wires with a cheap tester from RS or someplace like that. Between each wire and every wire and any metal, there should NOT be voltage present. If you've got a line tester, it's better. A meter, with its attendant high impedance front end, will often indicate "phantom" voltages where there are none. KN OW the difference, and how to tell, if you're not sure. THEN, when you're sure the wires are dead, touch them to each otehr and to any metal they reach, to see if they spark. NOW it MIGHT be safe to work on the wires.
You have done a very foolish thing that could h ave killed you had the current taken a route that went thru your heart. 120Vac kills very quikly; takes less than a second for it to throw the heart into spasms.
From now on, please consider getting a knowledgeable person in to handle such jobs. Or, LEARN the ropes!
Pop
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no matter how good your advice, every time you spout this garbage it kills whatever credibility you have. you have a better chance of dying from falling off the chair from losing your balance than from getting electrocuted.
be safe. be smart. dont be scared.
randy
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You mean like falling off the ladder when that "safe" white wire tingles you? It is NEVER "safe" to handle exposed white wires in an energized circuit. Any other EE dorm room chat about voltage drop and skin conductivity only tends to justify a practice that will eventually bite you. As you pointed out, it doesn't have to be the couple hundred MA necessary to cause V-fib, just enough to startle you and make you fall off the ladder.
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man it sure took some creative snipping and a hard head to arrive at this conclusion based on what i actually said..
did i ever say you shouldnt cut power at the breaker? did i ever say you shouldnt put test leads on to see if there is power? did i ever say it was 'safe'? no. no. no.
all im saying is that touching a hot wire isnt the instant death pop makes it out to be.
randy
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10-4 we are on the same page. sorry for the confusion.
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...

heart muscle into spasm. Or ventricular fibrilation as has been mentioned. That's not instant, but in the overall scheme of things, it's pretty hard to call it anything else. If you caught the voltage at its zero crossing, maybe you could touch it safely for about 1/600th of a second, but then on the other hand, touching it at one of its peaks for 1/600th of a second, if there is sufficient current behind it, could also put you into v-fib. I once knew an electrician who bragged about all the shocks he'd received, and how he could grab onto a hot wire without it hurting him. Actually, it can be done, but ... not reliably. He's no longer with us.
Pop
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i hear you. i understand what can happen. electricity 'can' kill you. i never bragged that i could touch a hot wire. nor would i even try it on purpose. thats just stupid.
nonetheless, by the numbers, you have a better chance, as an american, of dying from a terrorist attack than from being electrocuted. saws and drills are dangerous too, but you dont see someone posting about all the ways to die every time someone asks for help building a deck. people should be aware of the actual risks and actual safety procedures. if they are correctly followed doing electrical work is about as dangerous as building a deck.
if it were as dangerous as you make it out to be there is no way we would have the types of outlets we have in our houses.
randy
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electricity flow through the heart muscle. You do know, of course, that electricity, once inside the body, will follow blood vessels, right? I think you still need some education. Oh, and about my credibility: If that ruins it for you, then so be it - no skin off my nose if you can't be around tomorrow because you did something stupid.
Pop
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The neutral wire _carries_current_ if any load is in use on the circuit. It may be helpful to consider an analogy with plumbing: the black wire is the supply (pressure) line, and the white wire is the drain. If you take the trap out of the sink, and somebody turns on the faucet, you're going to get wet even though you never opened up the pressure line.
Electricity will ground through *all* paths available to it. This includes through your body, if you happen to be touching a _neutral_ wire at the same time you are grounded (even imperfectly grounded), because you have formed a parallel circuit with two paths. Certainly there will be more current flowing through the low-resistance path provided by the copper neutral wires than through the relatively high-resistance path provided by your body, but you can still get enough to kill.
*Never* work on energized circuits.
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"Doug Miller"

Wow - so many posts and only 1 correct response.
- Nate
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incorrect as they were incomplete. It's certainly true that many improper wiring methods (e.g. switching the neutral instead of the hot) could cause the neutral to be live.
The only incorrect posts I saw were the ones that falsely claimed that the neutral in a _properly_ wired circuit _cannot_ be dangerous.
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You could not get a shock off a white wire unless something was wrong.
The somethings could include using the white as a black without identifying it properly, putting the switch on the neutral side of the circuit instead of on the hot side, and a broken neutral connection.
Do not think you are safe because the wiring is 20 years old and nothing has happened yet. I just went over the wiring on my 40 year old cottage and found 4 problems (either wiring too small, or breakers too big) that could easily have burnt the place down. It was just good luck that it hadn't. My 20 year old house had an improper multiwire circuit that could have been fatal also.
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This is definitely *not* true. (Unless, in your category of "something wrong" you include working on energized circuits.)

Yes, and it can also include working on an energized circuit. If someone turns on a _different_ light fixture on the same circuit, there _will_ be current in the neutral wire.
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A properly connected white wire is always connected to ground. Since ground conducts many times better than you do, the amount of current you can get off a white is too trivial to matter.
If that is not true, give me an example.
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Your assumption that the amount of current flowing through your body "is too trivial to matter" is incorrect. It takes only a *tiny* amount of current, at 120V and 60Hz AC, to kill, if the ground path crosses the heart. Currents of as little as 50 to 100 mA _can_be_fatal_. Why do you suppose that GFCIs trip at 20mA?
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wrote:

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Are you really this stupid, or are you just being argumentitive for the sake of it? If you contact a white and a black, the average current will be about 60ma. Yes, 100ma can be fatal, but only if you have a prolonged contact. Anyhow, if you contact a properly wired white, your current will not be more than a few ma, even if you are well grounded. For example, the millions of electric dryers out there where the chassis is attached to the neutral; mine carries 7A, yet I can't get a shock off it even if my hands are wet. Can't come up with a counter-example? Of course not, there isn't one.
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per install specs, a maximum of about 1 volt in normal use. That's a hell of a lot less than say a 12V battery, or even the 48Vdc on your phone wires: The 48Vdc figure was arrived at as the highest "safe" voltage (actually it's 50VDC) that the human body can safely withstand. Again, he's talking current without consideration for any voltage potential necessary to cause current to flow. He knows enough to be dangerous, and safe, fortunately, inm this one case, but he's wrong. He needs to do some research before sounding off about "feels right" comments., Pop
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