why i HATE shared NEUTRALS!!

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dnem

Senior Member
Location
Ohio
Mike

I'm still waiting for an answer to my previous questions. As a teacher you should be able to explain yourself.

quoting jwelectric
If the fear is about the grounded (neutral) conductor that is present in the fixture and this conductor is part of a multiwire circuit would the equipment grounding conductor be as dangerous? Remember that the equipment grounded conductor is tied to the grounded (neutral) somewhere in the system. One conductor will be carring as much current as the other.
end quote

Did you say you were a teacher ?
Do you know that you posted that the equipment ground and the neutral "One conductor will be carrying as much current as the other" ?
Did you really mean to say that ?

Do you think that 2 wires that are connected together automatically carry the same current ?

David
 

jwelectric

Senior Member
Location
North Carolina
amptech said:
"If you get hurt while at work there is something that you could have done that would have prevented this from happening so it is your own stupidity that got you hurt."

In my eagerness to post I should have worded this a little different. This is one of my stupid moments. It should read like this.

If you get hurt while at work there is something that could have done that would have prevented this from happening so it is due to stupidity that got you hurt.

When I was typing my mind was on a statement that was made in an earlier post.
?There would have been 277v registered between neutral and ground, if I had checked.?

I am glad to hear that you Father-in-law was not hurt but as you have already stated his boss mad a very stupid mistake that about killed him

I too lost an eye, my right, in an accident that was due to the stupidity of someone else. In each one of these cases the accident was the result of something stupid someone did and could have been avoided with the proper preparation.
 

jwelectric

Senior Member
Location
North Carolina
dnem said:
I'm still waiting for an answer to my previous questions. As a teacher you should be able to explain yourself.

quoting jwelectric
If the fear is about the grounded (neutral) conductor that is present in the fixture and this conductor is part of a multiwire circuit would the equipment grounding conductor be as dangerous? Remember that the equipment grounded conductor is tied to the grounded (neutral) somewhere in the system. One conductor will be carring as much current as the other.
end quote

The question that was asked and I was addressing was

Originally Posted by DGrant041
How would you recommend changing a ballast in a light fixture (drop ceiling, 4 bulb flour.) in a hospital that could be on a MWBC?

When I cut the ballast loose from the circuit (not opening the grounded conductor) the short neutral that is left from the ballast will not be any more dangerous than the EGC.
Should someone open the grounded conductor to change this ballast and the circuit is still under load then there will be an arc. This is also true in a two wire circuit.

dnem said:
Did you say you were a teacher ?
Do you know that you posted that the equipment ground and the neutral "One conductor will be carrying as much current as the other" ?
Did you really mean to say that ?

Yes I am an instructor in the electrical field and am certified by the state of NC to instruct inspectors.

Yes I know that I posted that the EGC will be carrying as much current as the grounded (neutral) when it is part of a two wire branch of a multi wire circuit and the circuit is open.

Yes I did mean to say this.

dnem said:
Do you think that 2 wires that are connected together automatically carry the same current ?

Not at all. The amount of current that each would carry would be dependant on the impedance of each path and the voltage applied.
What I am saying is that a two wire branch from a multiwire circuit when the hot conductor is not energized the grounded (neutral) conductor will have no current.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
David,
Noone was intentionally working on the circuits while they were live. I'll post the example one more time so you understand the situation.
I disagree, and it doesn't matter why they were working hot...they were working hot. They did not do everything that they could to make sure that there was no shock hazard. They intentionally skipped steps that would prevent the accident.
Don
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
dnem said:
That second morning, when we checked the circuits that we were working on to make sure they were still off, none of us thought about the neutral. I could have ended up paying with my life. It was a lesson that I won't forget and I learned it without anyone calling me stupid.

I think the point is, David, that if this thread were named "MWBC Neutrals: The Silent Killer" your story would not fit in: It wasn't silent when you got nailed. A simple mistie could have produced the same results. Someone accidentally trims out a receptacle wrong and you're dead.

Anyone who digs in without checking all insulated conductors with at least a tick tracer is really playing with fire.

The "Silent Killer" aspect of this discussion has opened my eyes to the hole in my usual method, tapping around with a tick tracer to be sure everything's off. An in-use neutral would not glow and could hurt me. Now I have a tool on my bags to prevent myself from getting hurt from the silent killer.

I'd say Mike would be doing diplomacy a favor if he'd quit saying "stupid", but that's his choice. :D
 

jwelectric

Senior Member
Location
North Carolina
georgestolz said:
I'd say Mike would be doing diplomacy a favor if he'd quit saying "stupid", but that's his choice.

George I have given this a lot of thought and have tried to come up with a better way of expressing these actions. Here are a few words that I have come up with:
Doltish. A stupid person
Fatuous. Complacently or inanely foolish
Oafish (oaf.) a stupid person
I don?t think that any of these fit as good as stupid.
I know that this is not polite and the word is harsh and offensive and I am sorry if I have offended anyone.
I would rather be offensive than have someone keep doing unsafe work. If I can get them to see that what they are is nothing short of fatuous and they are being very oafish then maybe it will save an accident and maybe a life.

I used this scenario in an earlier post:
jwelectric said:
Here is a sernio that I sometimes use in the classroom.
I am sitting at a red stoplight and the light turns green. As I start to enter the intersection a car coming from the left hits me in the side.
Who is at fault?
This question has nothing to do with who will get the ticket or who is liable for the cost. The question is who is at fault?
Before you answer that question let me ask this. Is there anything that I could have done to prevent this accident?
See how stupid I was and spelled scenario wrong.
Using this scenario I would be plain stupid to assume that the car coming from my left is going to stop. I am responsible for my own safety and will stay put until I can see the car is stopping.
Although I had a green light and he had a red light I would carry some amount of blame and I would be stupid to think that the red light is going to stop the other car.

For lack of a better word I use the phrases ?stupid mistake and stupid accident? to describe something that someone does without thought or modus operandi.
Should you come up with a better way to describe these actions I am open to suggestions.
 

dlhoule

Senior Member
Location
Michigan
Mike says:
I have taught safety classes for five years and I am of the firm belief that any ?mistake? or ?accident? can be avoided.

Two people are assigned task of taking readings off meters in Sub Station. Transformer blows as they are leaving and they receive minor burns, temp deafness, and temp blindness. I considered this to be an accident. Should they have refused the assignment or what should they have done to avoid their injuries?

To try and work on any electrical circuit with out the proper training would be nothing short of stupid.

I am obviously a lot stupider than you; when I was 20 years old and still an apprentice I received my 1st elect shock. My foreman and my journeyman both told me a panel was fed from a certain breaker. They wanted to move the panel and were in a hurry. To make a long story short, there were 2 separate feeds coming into the panel; one was not shown on the print. I had the one locked out feeding the top of disconnect on panel and verified no power. I wound up getting a pretty good poke off of a 440 V lead feeding a motor starter. It is nice to get proper training at an early age, but I have found that it is possible to learn from ones own mistakes from time to time. How does one just starting out have the wisdom to know what proper training constitutes?

Mike, it sounds to me like you are a wonderful instructor. I wish I'd had some one like that when I first started.

Don, PPE wasn't thought of when above happened. I am a firm believer in using it where needed.

Have a great weekend all you intelligent people participating in this forum.
Okay, if there are any other stupid ones, (besides me) you guys have a grrr
rreater weekend!
 

dnem

Senior Member
Location
Ohio
georgestolz said:
I think the point is, David, that if this thread were named "MWBC Neutrals: The Silent Killer" your story would not fit in: It wasn't silent when you got nailed. A simple mistie could have produced the same results. Someone accidentally trims out a receptacle wrong and you're dead.

Anyone who digs in without checking all insulated conductors with at least a tick tracer is really playing with fire.

The "Silent Killer" aspect of this discussion has opened my eyes to the hole in my usual method, tapping around with a tick tracer to be sure everything's off. An in-use neutral would not glow and could hurt me. Now I have a tool on my bags to prevent myself from getting hurt from the silent killer.

There's no question that proper testing would have brought a different and much better result. We did test on the first day. We killed the 3 circuits and tested. We turned the one circuit that we weren't working on back on as we left that first day. The second day we confirmed the two circuits that we were working on were off but didn't test that second day.

Lesson to be learned: Test each time you return to the work area. Even if you leave for just a break, retest when you return.

Another lesson to be learned: You can be killed by the things you overlook even if your intent is to do the right thing.

David
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
dnem said:
Lesson to be learned: Test each time you return to the work area. Even if you leave for just a break, retest when you return.
I can't argue with that.
beerchug.gif


Mike, as always, I treasure your presence on this forum. Let's try an analogy:

You see "stupid" as a practical, non-offensive word.
Some folks see the Rebel flag as a symbol of Southern pride.
But there are others who see it symbolizing hate and racism.
Throwing "stupid" around so lightly can be tremendously, unintentionally hurtful to a broad audience.

I understand you because my Dad's the same way. A dictionary definition does not always utterly define a word.
baldguy.gif
 
georgestolz said:
I can't argue with that.
beerchug.gif


Mike, as always, I treasure your presence on this forum. Let's try an analogy:

You see "stupid" as a practical, non-offensive word.
Some folks see the Rebel flag as a symbol of Southern pride.
But there are others who see it symbolizing hate and racism.
Throwing "stupid" around so lightly can be tremendously, unintentionally hurtful to a broad audience.

I understand you because my Dad's the same way. A dictionary definition does not always utterly define a word.
baldguy.gif


Amen!! a dictionary definition does not always define a word. hopefull Mike sees the point of not using the word in a broad audience. :)
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Lesson to be learned: Test each time you return to the work area. Even if you leave for just a break, retest when you return.
If you lock the circuits out as required, there is no need to test after a break...just verify that your lock is still in place.
Don
 

paul32

Senior Member
Location
Minnesota
georgestolz said:
The "Silent Killer" aspect of this discussion has opened my eyes to the hole in my usual method, tapping around with a tick tracer to be sure everything's off. An in-use neutral would not glow and could hurt me. Now I have a tool on my bags to prevent myself from getting hurt from the silent killer.

What tool are you referring to?
 

wavector

Member
Location
Mobile, Alabama
I got nailed on a 277 volt neutral MWBC

I got nailed on a 277 volt neutral MWBC

The bldg. was the Army Corp. Of Engineers, in the south, and there were two services that fed the building. Two different sets of bus duct went up the nine floors on each end. Bus plugs fed the lighting panels on each floor times two (one on each end). The conduit systems were seperated, but some one had tied them together some where upline, and used the neutral from one panel for the MWBC from the other. I had turned off the MWBC that was supposed to be sharing the neutral I was connecting into and tested it (I failed to test the neutral because the wire was too short to get a probe in there under the wirenut - 277 neutral will test even if it's tied to panel terminal).

You know those old gray scotchlok wire nuts you have to cut off because they can't hardly be untwisted because they lock on? Well, with a new pair of lineman's I proceeded to untwist it because some yoyo left only about 2 inches of free conductor 3 wire twist. Well, to make a long story short the teeth on the new linemans went through the insulation of the wirenut and made contact with the steel sheel that covers the spring. I was on the grid and linemans. About 5 seconds before I hit the floor. The wirenut came off. But, I tasted silver for awhile, and I thought I was going to die. That's some bad stuff that 277 volt MWBC.

http://multimedia.mmm.com/mws/mediawebserver.dyn?LLLLLm0S1XzLEQT6eqM_2o4LywFlEvnVyo4Lyo4lkkkkk
 
Last edited:
wavector said:
The bldg. was the Army Corp. Of Engineers, in the south, and there were two services that fed the building. Two different sets of bus duct went up the nine floors on each end. Bus plugs fed the lighting panels on each floor times two (one on each end). The conduit systems were seperated, but some one had tied them together some where upline, and used the neutral from one panel for the MWBC from the other. I had turned off the MWBC that was supposed to be sharing the neutral I was connecting into and tested it (I failed to test the neutral because the wire was too short to get a probe in there under the wirenut - 277 neutral will test even if it's tied to panel terminal).

You know those old gray scotchlok wire nuts you have to cut off because they can't hardly be untwisted because they lock on? Well, with a new pair of lineman's I proceeded to untwist it because some yoyo left only about 2 inches of free conductor 3 wire twist. Well, to make a long story short the teeth on the new linemans went through the insulation of the wirenut and made contact with the steel sheel that covers the spring. I was on the grid and linemans. About 5 seconds before I hit the floor. The wirenut came off. But, I tasted silver for awhile, and I thought I was going to die. That's some bad stuff that 277 volt MWBC.

http://multimedia.mmm.com/mws/mediawebserver.dyn?LLLLLm0S1XzLEQT6eqM_2o4LywFlEvnVyo4Lyo4lkkkkk


So another vote for seperate neutrals. :) I agree, that 277 is NOT fun to get hit by. Be more careful next time. And just for the record, I do NOT think you were 'stupid' even though someelse may call u that. :)
 

peter d

Senior Member
Location
New England
I haven't read this thread. I have no intention of doing so as I would like to preserve my eyesight.

The company I work for uses them all the time. We will continue to do so. We are trained to know how to install and troubleshoot them. We don't make considerations for untrained people working on MWBC circuits we install.


End of story.
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
paul32 said:
georgestolz said:
An in-use neutral would not glow and could hurt me. Now I have a tool on my bags to prevent myself from getting hurt from the silent killer.
What tool are you referring to?
Come on George pony up. Was that your tongue, or something more sensitive?
 

mario

Senior Member
Location
Alaska
wow, what a thread ...

wow, what a thread ...

couldn't sleep so I finally read the complete thread (started at 1:30am; now 3:30 ..Alaska time , and yes it is starting to get daylight out; didn't get dark till 11 pm) .. WOW .. talk about diversity of opinions .. I Love it .. I too learned young about "Paying Attention" to my work (second week of apprenticeship, 30 years ago). While holding an "amp-probe" on a wire on a motor starter and hollering out readings, I "allowed" my finger to make contact with the top screws of 2 phases of the motor "Heaters" ...... ggeeezzz ...... 440 to the finger .. burned a hole in top and bottom knuckle; bounced a few times in the confined space I was in (before clearances were really understood; platform with 20 or so motor starters, 10 on each side, less than 2 feet from front of each door) arm was numb for an hour, finger for a couple more ...... bottom line ... I agree with Mike; although I don't like to use the term "stupid" ... "SAFETY" should always come first ... accidents only happen when we aren't paying attention to what we're doing ... our own fault ... I believe all "Mishaps" are preventable ... may sound dumb, but , look before you leap ... I've gotten "Hit" a few more times since my first and each time was because of something I did "WRONG" ... and yes "STUPID" ... BTW ... each had to do with a "shared Neutral" ... enjoy the weekend guys/gals ... remember ... "NOBODY GETS HURT" ... M
 
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