ECN Forum Forums General Topics of the Trade General Discussion Area 'Nailed by Neutral'

Maybe a question for you engineers:

Is there any truth to the claim that a neutral shock can be worse than a shock from a phase wire?

If the current is passing through a motor or a ballast is there an inductive kick, or do people just "not expect" to get hit from a neutral so it's that much more of a surprise?

-John

I have taken to checking neutral wires with my Fluke non contact tester as soon as I open them up. If there is current, it will light up the tester as soon as you interrupt the path.

My dad has said (and I'm not sure if he's joking) that sparks must not be depressed very often, what with the random, low-grade, electroshock therapy the receive. As therapeutic as it might be, I still don't think it's a good thing...

Well, lets look at that neutral current for a moment....

For a simple two-wire circuit, the only way the neutral can be "hot" is if the current has passed through a load. If the load is a simple resistance (like a light bulb), then you're going to feel reduced voltage, at 60 hz.
If it's a load that has capacitors in it (like a fluo ballast), those caps are going to give you an extra "kick." Sort of a "mini-stun gun."

For multiwire circuits, the current on the shared neutral will be combined. As I see it, the voltages will both add to each other, and merge .... meaning that the voltage will approach 208, and the current waveform will begin to look more like a "DC" line than a sine wave. This means a bigger contraction in your muscles- and a greater chance of not being able to let go.

The 'advantage' here to a shared neutral is that the loads are also exposed to the higher voltage ... so they might fry before you do! I wouldn't count on it, though.

My two "Neutral" stories... both took place before I officially entered the trade.

I was a H.O. who was using stuff his Dad taught him to re-wire his house from the old linen covered, rubber insulated stuff (not even sure of the Code designation, since it got kiboshed about the time they stopped allowing knob & tube for new installs) with brand new THHN/THWN.

It was entering early evening, and Doug, working by fading sun and a trouble light, had just finished re-pulling a run of #12 into a box in the basement mounted on the floor joists above.

In the process of marrying the new wire to the old. I had turned the breaker for the circuit off, and had just tied in the hot, and was stripping the neutral, when the tip of my Kliens touched the back of the junction box.

POP! A bright blue flash overhead, and there goes the night vision.

Upon examination, my #12 strippers were now #10 strippers.

I walked over to the panel and killed the main to do the last three hookups.

Later in the same adventure, I had finished re-running new wire in the upstairs bedrooms, and had walked downstairs to re-power the circuit.

As I came back upstairs, I rounded the corner of the stairs to the second floor and I saw this unearthly glow coming from the bedroom closet I had just been working in. It appeared that there was a fire in the closet.

As I rushed into the bedroom, I realized that the glow was coming from the bulb.

Apparantly, the "hot" feed to the bedroom hadn't been tightened enough, and had popped loose, leaving the last lamp in the circuit as the one in the bedroom. It was being backed somehow, and had just enough voltage going through it from the lamps in the other rooms to illuminate.

Scared the hell outta me.


[This message has been edited by DougW (edited 12-09-2006).]