A little electricity 101 if you please

[Eigenvector]

A couple three basic questions that I'm not willing to test myself.

When pigtailing wires together, you won't get shocked so long as 1) the breaker to that circuit is off 2) you aren't touching both the neutral AND the hot wire. Meaning, if I grab two hot wires and pig-tail them (like when adding in a dimmer) I won't get shocked so long as I'm not touching the neutral wire AND the breaker to that circuit is off. I'm not trying to be ultra safe here so much as I'm trying to make sure that in situation where switching off the breaker isn't a guarentee that power is off for that fixture.

Second question, if I take the probe leads from my volt meter and jam them into an outlet, it's not gonna short the circuit but do exactly what I would expect it to do - read the potential difference between the two sockets in AC volts (assuming your voltmeter is reading AC volts).

And finally, when splicing phone line, do the wires normally carry voltage sufficient to shock or could you essentially splice them with your teeth if you had to?

[DanG]

The phone lines are safe. You won't feel any shocks.

Power lines are a bit different.There should not be power on the colored power wire, usually black, when the breaker is turned off. Neutrals, the white one, are usually shared by two circuits. In a perfect world there should not be power on the neutrals if everything is wired correctly. DO NOT assume so. You do not tell if your wiring is new enough to have a ground, either green or bare. Turn off the breaker, check between black and white - no power; then use your tester between the black and the green - no power; use your tester between the white and the green - no power, you're good to go.

It is good practice to never use both hands around electricity that can allow current through your heart. If you are not grounded, barefoot, in a puddle of water, or some other grounding you might feel a tingle, but the current can't go through you. I am not suggesting this, but some old electricians might use their finger in a light socket to check for power.

[Doug Miller]

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.

[Toller]

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.

[RBM]

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

[Doug Miller]

False.

[RBM]

Personally, I feel that I have better control over my well-being when I use both of my hands when handling live wires and devices. I also try to use my head

[DanG]

I agree with you totally, but the advice is for someone who is uncomfortable and on new territory. He is not asking how to work something hot.

[DanG]

I agree with you totally, but the advice is for someone who is uncomfortable and on new territory. He is not asking how to work something hot.

[Doug Miller]

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.

[Doug Miller]

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.

[RBM]

I agree on both counts, although, opening a live neutral and getting between the conductors is a guaranty of pain.

[Eigenvector]

I appreciate the swift responses. I am relatively new to doing this kind of repair work and so there were these questions that came to mind. I had to replace the dimmer, I've seen it done and know how to do it, but wires won't show electricty in them, so before grasping them to undo the pigtail I grabbed my voltmeter and touched the wires. I didn't see any readings so I thought - Hmm maybe my voltmeter isn't working. So I was about to stick the probes in the outlet when the thought occured to me that maybe that isn't such a smart idea either. So I figured, why not, I'll ask here and save myself a trip to the emergency room and only pay the price of looking stupid.

[Doug Miller]

Outstanding idea.

[RBM]

When in doubt... Throw the main

[Al Schmidt]

If you get a ring pulse while doing wiring its another matter.

[professorpaul]

There is a disconnect in modern phone boxes. Just to be on the safe side, disconnect you line there before you work inside.

[Tom J]

AHH!! Bingo!!

Tom J been there, felt that

[Eigenvector]

Assuming your panel has main that is....

[Steve Barker]

I'll answer only on the telephone thing. I've forever stripped phone wire with my teeth, BUT, be advised from my understanding, there will be about

90 volts DC if the phone were to ring.