Electrocuted from neutral

[wiz561]

Hi!

I have a quick question and wondered if somebody can explain this to me. While working on some wiring today, I got a bit of a jolt from the neutral wire. When I tested it with my voltmeter, it read zero (I had the breaker off). But then, when I grabbed the neutral, I got a tingle.

I took my voltmeter and tested it, and it peaked up around 1 to 2 volts, then dropped back to zero. Did it again a few minutes later and the same thing.

Upon further investigation, I found that there was one neutral that was going to the furnace (on one circuit) and then up to the sockets on the other circuit. One circuit (the furnace one) was live while the other was dead.

Just so I understand, is the reason why I got a tingle was because electricity was flowing through the live circuit? If I turned off the circuit for the furnace along with the other one, would this have prevented me from getting a little shock? I read one posting that said to use the clamp to check for amps. Should I have done this along with checking out how many volts are running through it?

Thanks!

[John Grabowski]

*The neutral is a current carrying conductor. It sounds as if the one that you are referring to is part of a multiwire circuit that is shared with the furnace. When the furnace comes on there will be current flowing through it. You should treat it like a live wire even when the circuit breaker is off.

[sligoNoSPAMjoe]

[sligoNoSPAMjoe]

You can get a real jolt from a neutral under the right/wrong conditions. ___ Neutrals are current carrying wires.___ Always treat them as such. They are NOT GROUNDS.

[Jim Elbrecht]

Just for clarity can you explain how you were "electrocuted" and are still able to post to Usenet?

Was the 'death of Usenet that we've been hearing about for a decade a statement on the status of the posters?

A 'bit of a jolt' is hardly electrocution.

Jim

[wiz561]

This is a good rule to practice...but how do you test for this?

Thanks for the responses...

[Art Todesco]

Also, remember this is not a purely resistive circuit. You have a motor and even some inductance in the wires. Even turning on an incandescent lamp produces a short high current until the filament warms up. So, you can get current spikes when starting motors and lamp, which can produce voltage spikes on the neutral of a circuit which is not purely resistive. .

[Michael Dobony]

This is probably why the new electrical code does not allow sharing neutrals between circuits. You may want to check to make sure the light circuit is on a different phase than the furnace. Neutrals should never be shared on common phase circuits.

Also, get off googlegroups. Many wise NG users block googlegroups because google refuses to deal with NG abusers. Blocking all posts originating from googlegroups eliminates about 90% of the trash posts!

Mike D.

[Doug Miller]

It does nothing of the kind.

[Bill]

A Multi-Wire Branch Circuit (MWBC) is two hot wires on separate breakers sharing one neutral.

If just one breaker is turned off, the neutral is still carrying electricity for the other circuit. If you disconnect the neutral and something is turned on upstream to the still energized circuit, the upstream neutral will be like a hot wire!

For this reason, new code requires a double pole breaker for a MWBC or both breakers to be tie bared. Then both circuits must be turned off at the same time.

And for this reason it is a good idea to turn off power to the entire house before doing electrical work.

[Steve Barker]

and work in the dark..... ya, ok.

s

[Michael Dobony]

so several electricians and inspectors are wrong?

[George]

Thats why rules are codified. Ask them to show you what rule disallows shared neutrals. About the only common requirement for the typical residential shared neutral installation is that the circuit breaker handles must be interlocked if the outlets are split wired.

[Steve Barker]

No, i'd say several HUNDRED inspectors and electricians are wrong. And not just about this topic.

s

[John Grabowski]

This is a good rule to practice...but how do you test for this?

*No test. When handling the conductors treat them as though juice was flowing. Tape up the bare ends, don't touch the ends, don't let them come in contact with anything else, keep one hand behind your back, etc. I am used to working with hot wires so it is easy for me.

[E Z Peaces]

Did you have the neutral disconnected when you touched it? That might explain how there could be enough voltage to feel. If the neutral was grounded, maybe the conductor the other probe touched had voltage.

If the meter registered only momentarily, that sounds like a DC charge. A spike of more than 100VDC might show only a couple of volts on a DMM set for AC or DC.

In the furnace, I suppose the voltage could come from a capacitor charged through a diode. Maybe the source was instead static generated by air flow in the furnace.

[Van Chocstraw]

Neutrals are live! That's why when you put your ladder near the power line that goes into your meter and touch the bare neutral you die.

[DanG]

Since when? Can you cite an article from the NEC?

[hallerb]

Back in 1975 I was a brand new service tech just out of high school and fresh from manufactuers training, I was nervous but wanted to do EVERYTHING just right!

Went to a stock broker in downtown pittsburgh working by reception desk and this gorgeous beautiful model type who was the receptionist.....

long blonde hair, big heels and short dress, but tasteful she decorated the office:)'

Anyhow In servicing the machine I followed my new training closely:)

INTENTIONALLY overheated the machine to test the safety switches, which worked fine. let the machine cool, crouched down to reach the reset switch.

pushed it and a ball of fire came out of machine, no electric shock but stunned I went from crouched down to flat out on floor, looking up gals dress.

The entire office of perhaps 50 people went silent, probably thinking someone just died, and fireball was large:( the click clak of typewriters stopped you could hear a pin drop

Dumb blonde kept asking if I was electrocuted.... third time she asked I was getting up and said if I were I wouldnt be talking to you:)

Anyhow didnt know what I did wrong I finished fast got out of there and went back to our office, when I told my boss what happened he said call the guy who trained you.... Hey I get to call chicago on this job.:)

Trainer when told of my excitement said after you guys left we realized we forgot to tell you guys to always unplug machine before resetting! otherwise a fire ball will come out of machine:(

Well it does and it did we agreed he should call the other trainees, and warn them:)

its rare to remember a specific thing that happened so long ago.

excitement wise it ranks right up there with the day I ran a borrowed gasoline garden tiller into the service entrance of our house:(

[hallerb]

the neutral is the TOP wire of the old style 3 wire overhead lines. Put on the top to help dissipate lightning and high voltage if a high voltage line from above breaks and falls on it.

properly grrounded at each service touching a neutral shouldnt kill you, although you might feel a little tickle