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Unread 07-08-2019, 10:07 PM   #21
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If you're just demoing lights, cut the neuch for the whip your working on at the connection leaving yourself enough sticking out of the wirenut to cap with a yellow, or tape it. No need to open the splice. Just don't ground yourself while cutting.
This is exactly what I've been doing. Plus I wear Class 00 gloves with leather gloves on top for good measure, especially when I have to shove a bunch of spliced wires into a 4x4 box (they're 347v). I have many of my colleagues suggested doing this. However, just like most of you here, no one really knows how to test if a shared neutral is live.

Also I've been a bit of a long time lurker, I've noticed a bunch of people here strongly advising not working on live, yet an equal number of people suggesting you're not a real electrician if you cannot work on live.

For me, it took me a while to get over the fear of working on 120V live at first. For me to do it comfortably, I had to watch someone else do it. Everything from changing a receptacle live, splicing a bunch of hots together, splicing neutrals together live (with 120v, its not a big deal), and tying circuits into a live panel. All of this freaked me out to the core and people had to educate me on how to handle electricity properly. Obviously 347v is a different beast altogether, and I'm kind of surprised there really isn't a method to detect a live neutral aside from taking precautionary measures like cutting the neutral off a bx whip as someone suggested and capping it off.
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Unread 07-08-2019, 10:23 PM   #22
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Me too. No one should be working on live circuits unless your licensed and only troubleshooting. Definitely should not have a brand new worker doing it.


Just to clarify, he did not graduate from a trade school. He paid for a money grab, pre apprentice scam of a school where everyone graduates as long as you pay. They charge $9000 for 3 month program that gets you nothing. No hours toward a real apprenticeship, no real trade school exemptions.

Sorry, these pre apprentice money grab scams are a bit of a trigger for me.

I've seen a guy that went through a program like this. He paid $30k for a TWO YEAR DEGREE and he wasn't half as capable as I was with my fully accredited AAS in Mechatronics. I busted hump and got scholarships. I actually made about 1.5k per semester to go to school provided I maintained my grades for the last 3 semesters. All-in-all, the degree costs about 10k with me getting pre-reqs out of the way for engineering school.


I preach against them just as heavily. It sucks when these kids come out thinking they are learning something when they really aren't.


That aside though, this kid *thought* he knew what he was doing. There is a place in the acquisition of knowledge where you don't know what you don't know.
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Unread 07-09-2019, 01:00 AM   #23
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This is exactly what I've been doing. Plus I wear Class 00 gloves with leather gloves on top for good measure, especially when I have to shove a bunch of spliced wires into a 4x4 box (they're 347v). I have many of my colleagues suggested doing this. However, just like most of you here, no one really knows how to test if a shared neutral is live.

Also I've been a bit of a long time lurker, I've noticed a bunch of people here strongly advising not working on live, yet an equal number of people suggesting you're not a real electrician if you cannot work on live.

For me, it took me a while to get over the fear of working on 120V live at first. For me to do it comfortably, I had to watch someone else do it. Everything from changing a receptacle live, splicing a bunch of hots together, splicing neutrals together live (with 120v, its not a big deal), and tying circuits into a live panel. All of this freaked me out to the core and people had to educate me on how to handle electricity properly. Obviously 347v is a different beast altogether, and I'm kind of surprised there really isn't a method to detect a live neutral aside from taking precautionary measures like cutting the neutral off a bx whip as someone suggested and capping it off.
The thing with shared neutrals is, if the loads are balanced, there is no current on the neutral, and no voltage because it's at ground potential. But opening it can put phase to phase voltage on 2 separate phase to ground loads. That's bad for computers, and lights.

The main thing you HAVE to remember when working with shared neutrals is to not ground yourself, that means to "T" bar, cement floors, tile, ceiling wires, conduits, fixtures, etc. "T" bar grid is a mother father to work around when you have some live and some not in the same box. Another thing to remember is to keep the wires in control. Don't let them "flop" into a box, or you when you take off wirenuts. Tape is your friend.
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Unread 07-09-2019, 05:45 AM   #24
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I've been in the trade for almost 40 years and can vividly remember every single time I was hit with 277. Every one of them was within the first 10 years in the trade. That's when I knew everything.

I also hate when 277 lighting circuits blow up in your face too.
I turn it off or find a very safe way of doing the job.
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Unread 07-13-2019, 06:32 PM   #25
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I’m in the camp of turn off the power. I am not scared of electric shock, but I do respect it- 14 years in the field, and I used to think it was some bad ass if I fixed a problem live. But as time grows on I realie that there is no reason to take repeated risks on a large job like that. Shut it down. If things are so badly labeled you have no idea, it needs to be brought to the supervisor’s and safety manager’s attention. In writing if you are smart. That way when you get electrocuted and killed your family can sue and make some money.

The only safe way to do this is to shut down power. Convenience is secondary to safety.
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Unread Yesterday, 04:30 AM   #26
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I’m in the camp of turn off the power. I am not scared of electric shock, but I do respect it- 14 years in the field, and I used to think it was some bad ass if I fixed a problem live. But as time grows on I realie that there is no reason to take repeated risks on a large job like that. Shut it down. If things are so badly labeled you have no idea, it needs to be brought to the supervisor’s and safety manager’s attention. In writing if you are smart. That way when you get electrocuted and killed your family can sue and make some money.

The only safe way to do this is to shut down power. Convenience is secondary to safety.
This is what cracks me up about people who say they could not find the circuit in a badly labeled residential panel. I can find it. It's called the main breaker. Turn it off if you have any doubts about which circuit is controlled by what breaker. Then work on the circuit. Applies even more in commercial work, and I'm fairly certain even more than that in so called industrial work. Higher voltages are very unforgiving. And the potential to deliver a lot more amps to the short circuit or ground fault grows exponentially with the larger facilities. This ain't no place to be making short circuits or being in the proximity during an arcing event.
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Unread Yesterday, 08:05 PM   #27
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I've been in the trade for almost 40 years and can vividly remember every single time I was hit with 277. Every one of them was within the first 10 years in the trade. That's when I knew everything. [IMG class=inlineimg]https://www.electriciantalk.com/images/smilies/vs_laugh.gif[/IMG]

I also hate when 277 lighting circuits blow up in your face too.
I turn it off or find a very safe way of doing the job.
more people are killed working on 277vac hot. Cut it off
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Unread Yesterday, 08:07 PM   #28
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Put an amp probe on it or ohm it to ground
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Unread Yesterday, 10:30 PM   #29
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Put an amp probe on it or ohm it to ground
Unless I'm misunderstanding you, what good would ohming it to ground do? If it's by itself or shared, you'll see it as a short to ground (assuming the panel end is properly bonded).. If it's shared, and you disconnect it, you'll run that current through your meter to ground..
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Unread Yesterday, 10:57 PM   #30
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Unless I'm misunderstanding you, what good would ohming it to ground do? If it's by itself or shared, you'll see it as a short to ground (assuming the panel end is properly bonded).. If it's shared, and you disconnect it, you'll run that current through your meter to ground..

Ohming to ground would accomplish nothing, I agree.


Putting an amp clamp on it accomplishes little. You can have that neutral carrying little to no current but the entire situation changes when you open a phase.


I'm going to go ahead and say here that it is my belief that this is incorrect information and/or bad advice and OP should disregard it.
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Unread Today, 08:38 AM   #31
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I meant to say measure with your meter the neutral your are talking about will show voltage if it is shared neutral and has a load on it
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Unread Today, 08:48 AM   #32
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I meant to say measure with your meter the neutral your are talking about will show voltage if it is shared neutral and has a load on it
???

It will always have voltage, load or no load
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Unread Today, 11:33 AM   #33
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Put an amp probe on it or ohm it to ground
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Originally Posted by glen1971 View Post
Unless I'm misunderstanding you, what good would ohming it to ground do? If it's by itself or shared, you'll see it as a short to ground (assuming the panel end is properly bonded).. If it's shared, and you disconnect it, you'll run that current through your meter to ground..
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I meant to say measure with your meter the neutral your are talking about will show voltage if it is shared neutral and has a load on it
Where did I say to test for voltage on the neutral? You said to ohm it to ground. Unless I'm missing it, "ohming to ground" tells me that you want your meter set on omega and are trying to measure resistance to ground. If you try this stunt and and you have broken a shared neutral on the homerun side, you're meter will take the fault current through it when you go from ground to a neutral...

Why is it so tough to isolate the circuits and do it properly? He11 isolate the main for the time it's gonna take. Do it on a Saturday.. After hours.. Whatever it takes...Let me know what Z462 tells you about working live on a 347 volt LIGHTING circuit so you didn't have to interrupt someone's work day..
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Unread Today, 07:34 PM   #34
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Why is it so tough to isolate the circuits and do it properly? He11 isolate the main for the time it's gonna take. Do it on a Saturday.. After hours.. Whatever it takes...Let me know what Z462 tells you about working live on a 347 volt LIGHTING circuit so you didn't have to interrupt someone's work day..
Its not tough to isolate the circuit by turning off the breaker. Its tough to prove that you have isolated the circuit which causes a problem.

Something like a nightlight circuit bugged of a the wrong neutral can cause a surprise so treat the neutral as a hot and use ppe. (after years of upgrades just about any other circuit could be bugging the neutral)

Im glad i invested in a quality tracer years ago. Simply clamp the ring over a wire dead or alive and it will be easy to find in the panel.
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