A little electricity 101 if you please

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snipped-for-privacy@milmac.com (Doug Miller) wrote:

snipped-for-privacy@earthlink.netttt (Charles Bishop) wrote:

I wouldn't. Is the voltage due to the resistance of the dimmer? You don't see voltage between the terminals of a regular switch do you?

Interesting. I'll check next time I get a chance.
--
charles

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In article
snipped-for-privacy@earthlink.netttt (Charles Bishop) wrote:

Then you should alter your expectations to conform to reality. :-)

No, the light bulb(s), as I noted.

Yes -- you should try it some time.

Do that.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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bull.
you'll feel them if you strip them with your teeth, like the OP asked.
although it is only a little tingle, unless someone calls at the exact moment you have the wires in your mouth. found out the bad way.......
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wrote:

Obviously I'm not gonna be stripping phone line with my teeth, there are better tools for that. But by using that case it is easier to make a point about what's in a phone line.
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On Sun, 11 Feb 2007 08:45:43 -0800, "Eigenvector"

Yes. The important thing about teeth is often that you have them with you.

--
Mark Lloyd
http://notstupid.laughingsquid.com
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<...snipped...>
Usually, but I can still work on wiring without them, :)
--
Better to be stuck up in a tree than tied to one.

Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf.lonestar.org
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Not true. The on-hook (phone just sitting there) voltage is nominally 48 V, which you probably won't feel unless your skin is wet. (Don't try putting your tongue across the terminals though!).
But the ring voltage is something like 90-100 V, so you will feel that if you're holding onto the phone conductors when someone tries to call you.
    Dave
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On Sun, 11 Feb 2007 03:52:43 +0000 (UTC), snipped-for-privacy@cs.ubc.ca (Dave Martindale) wrote:

12V it getting strong for that (using the tongue as a voltage tester). It works OK with 9V batteries. And that's DC. IIRC I've never tasted AC, but I hear it's even stronger.

I have described the feeling of such voltages as "a thousand hyperactive ants just under the skin".
--
Mark Lloyd
http://notstupid.laughingsquid.com
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Assuming that the circuit is connected to *only* that breaker, and has no cross-connections to any other circuit, you can stop there -- killing the breaker is all you need.

If the circuit is off, you won't get shocked even if you *do* touch the neutral. Assuming, again, that everything was installed properly.

The only way that switching the breaker off *isn't* a guarantee that power is off, is if the circuit has been installed improperly, with a cross-connection to some other circuit.
Do you have a specific reason to be concerned that the fixture you're intending to work on won't be de-energized by killing the appropriate breaker?

Correct.
They carry enough that they could sting a bit, and I certainly wouldn't splice them with my teeth -- but there's no danger from working with live phone wires.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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As long as the breaker is off, you can't get a shock. I always test for voltage before touching a wire. The neutral is just a really good ground; neither more dangerous than a copper water pipe, nor less. (The exception is when the neutral isn't attached to the breaker box properly; then it can be dangerous, but that would be very unusual.)

That's correct. Just be sure you have the meter set correctly, or you might be surprised.

Phone lines are harmless.
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wrote:

Well, close -- as long as the breaker is off, *and* everything is wired properly... and that's something that you can't necessarily assume. In two of the three houses I've owned, I've found one pair of circuits that had their neutrals cross-connected. When somebody does something stupid like that, all bets are off.

That's good practice. *Excellent* practice is to apply the tester to something that is *known* to be live first, to make sure that it properly indicates the presence of voltage.

Wrong, wrong, wrong, wrong.
PLEASE stop answering questions like this until you figure out the difference between neutral and ground. THEY ARE NOT THE SAME.
The neutral _carries_current_ under normal operation, and you _can_ get a lethal shock from the neutral conductor of an energized circuit.

Wrong again. I repeat: the neutral is a current-carrying conductor under normal operation, and touching it can be lethal.
Electricity does *not*, as is commonly and mistakenly believed, follow "the path of least resistance". Instead, electricity follows *all* *possible* paths. And that's why the neutral of an energized circuit can be dangerous: by touching it, you create a possible path for current through your own body.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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Toller wrote:

...
Based on the number of open neutral questions we get around here, I would not say it is very unusual. Unusual maybe, but I would not bet my life on it, especially if I were working on a application I did not trust.
--
Joseph Meehan

Dia \'s Muire duit
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If the breaker is off to a circuit, it's dead: Except if it's an Edison circuit, one that shares a neutral between two legs of different potential. In this case you would need to turn off both breakers sharing the neutral, or else, opening the pigtail of the neutral and getting between the conductors will hurt you

Correct
There is enough voltage to hurt you especially if your hands are sweaty
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this)@optonline.net> wrote:

You don't need to open the pigtail and get between the conductors to get hurt. Simply touching it may be dangerous: you create a [potential] parallel path for the neutral current, through your body. Electricity follows all possible paths, not just the one of least resistance. Creating additional paths with your flesh isn't a good idea. [snip]

Let's clarify that, OK?
"Enough voltage to hurt you" meaning "enough to cause pain", yes. Meaning "enough to cause injury", no.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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I agree on both counts, although, opening a live neutral and getting between the conductors is a guaranty of pain.

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If you get a ring pulse while doing wiring its another matter.
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There is a disconnect in modern phone boxes. Just to be on the safe side, disconnect you line there before you work inside.
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wrote:

In the 50's we had metal boxes and when you pulled up on the cover to remove it two ceramic/copper tipped fuses could be pulled to disconnect. My granddad would pull the fuses when he had enough of my siblings talking on the phone <G>. If he left the house with a fuse, my brother would put two forks in place of the fuses, so they could talk.
It's pointed out (with older phones) to take phone off the hook in another room, before working. I don't know about modern phones (digital/wireless).
I have the newer box for the disconnect as you mention. Labeled on the box - "Customer Access" . -- Oren
"Well, it doesn't happen all the time, but when it happens, it happens constantly."
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Al Schmidt wrote:

AHH!! Bingo!!
Tom J been there, felt that
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Re phone lines=---It is very possable for a phone line to have enough current to get a good shock. Telephone lines have a standing voltage of 48vdc and super impossed ac of up to 100 v. for ringing but very low amps. So if you are working on a phone line and ringing currant comes across that line you would feel it. It could startle you and make you fall off of a ladder etc. Allways be careful.
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