# The very rare shocking story



## macmikeman (Jan 23, 2007)

So, changing out a panel. What do you usually do? Turn off the main breaker for the panel in question. Lock out and tag it? Then double triple check the target panel for voltage next after removing the panel cover? I bet most every one of us at least double triple checks for zero voltage on the panel in question, who wouldn't? Me, I use my wiggle or fluke and check everything. Then I run my volt tick around the panel in case something is fed from elsewhere and is just traveling thru the panel and fed from elsewhere. Usually that step comes out when there is a whole lot of wires in that panel and not easily visible to follow all wires to see where they come from to where they land. 

*But that panel might still not be safe to swap out yet.*

What are you talking about macmikeman? Is this another conspiracy story? No. 

Here is the last test to make which no one does, except for me now since I got a nice little whack a few days ago while swapping out a residential panel. Take out your clamp on amp tester and test for current flow in the neutral feed and the ground feed to the panel. See? I never used to do that one step. I will from now on. The panel I pulled the other day had neutral current (4.5 amps to be exact) running on it even after killing the sub panel breaker. Whoda thunk? Unscrewed the 2 hots and pulled em out of the main lugs. Then I loosened the neutral feed and while grabbing it to pull it out somehow or other touched the uninsulated end of the wire with one hand and was holding on to the panel for leverage with the other hand and bingo, right thru the heart path. Hand to hand. I'm quick to let go . No big deal. (time for comment boys, have at it). 
Up in the attic in a junction box, I found where there was a circuit from the panel I was working on mixed with a circuit splice from another sub panel in the house. All of the neutrals in that junction box were tied together. I found it quick because when I opened the neutral and got whacked, after that the lights in the area on the floor above me in the kitchen , dining , and living room went out. So I knew where to go looking and found it. 

So I am taking the time now to put this out there- AMP TEST THE WIRING BEFORE YOU BEGIN TO DISASSEMBLE , VOLT TESTING IS NOT ENOUGH.. And also a tipoff is multiple sub panels , that is something to look for when changing *one* of them.


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## cuba_pete (Dec 8, 2011)

Glad you’re safe, honestly. No need to work you over, sure you’re doing enough of that. 

I do this (checking neutral and clamping wires) regularly due to long runs that pick up even induced voltage that scares the crap out of me when it lets out those little sparks, and I’m like WTF?


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## macmikeman (Jan 23, 2007)

cuba_pete said:


> Glad you’re safe, honestly. No need to work you over, sure you’re doing enough of that.
> 
> I do this (checking neutral and clamping wires) regularly due to long runs that pick up even induced voltage that scares the crap out of me when it lets out those little sparks, and I’m like WTF?



Thanks. There is upside to this. I got paid to locate where the original feed to upstairs lighting neutral was disconnected. It was in the other panel. Somebody must have gotten shocked down there as well so they just taped it off.


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## VELOCI3 (Aug 15, 2019)

Backfeeds are more common than you think. Especially when running separate HR’s from normal and emergency panels. Happens in office spaces a lot especially when moves or changes are made after the initial installation. Not as common in residential because most houses have only 1 panel. 

I like to kill the panel feeder and leave all the branch breakers on (backfeeds to breakers happen). Then test the phases to ground and neutral. Then pull the main neutral out and tap it on the neutral bus to see if it sparks. 


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## cuba_pete (Dec 8, 2011)

Wow...I hate finding that crap. I open a panel in my facility with a contractor and get embarrassed...I’m like who the heck got in behind me and did that?


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## macmikeman (Jan 23, 2007)

VELOCI3 said:


> Backfeeds are more common than you think. Especially when running separate HR’s from normal and emergency panels. Happens in office spaces a lot especially when moves or changes are made after the initial installation. Not as common in residential because most houses have only 1 panel.
> 
> I like to kill the panel feeder and leave all the branch breakers on (backfeeds to breakers happen). Then test the phases to ground and neutral. Then pull the main neutral out and tap it on the neutral bus to see if it sparks.
> 
> ...


I never pull out anything neutral on any commercial work ever without amp testing it first. Cardinal Rule. Gotta make that for residential work now too I guess.


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## MTW (Aug 28, 2013)

Panel changeouts are always where I find double fed circuits, usually in an explosive fashion.


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## 99cents (Aug 20, 2012)

Thank you, mac, for being right.


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## macmikeman (Jan 23, 2007)

MTW said:


> Panel changeouts are always where I find double fed circuits, usually in an explosive fashion.


Yes, but like I said, I always check for those kind- where there is still voltage. but who looks for zero potential after checking for potential?


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## MTW (Aug 28, 2013)

macmikeman said:


> Yes, but like I said, I always check for those kind- where there is still voltage. but who looks for zero potential after checking for potential?


Generally, but not always, I make it a practice to put my tick tracer on every single wire including neutrals and grounds once removed from the bus bar, because it will pick up a "live" neutral as you know. Those times when I don't are when I get a surprise.


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## macmikeman (Jan 23, 2007)

MTW said:


> Generally, but not always, I make it a practice to put my tick tracer on every single wire including neutrals and grounds once removed from the bus bar, because it will pick up a "live" neutral as you know. Those times when I don't are when I get a surprise.


Not all tracers pickup "hot" neutrals. Mine didn't. Others I have owned would. I clearly remember running my tracer (orange brand with red tip, the one that goes blue for dead and read for live) over and around all the neutrals in the can before I even touched any wiring. All I saw was blue light. 


Later I made a jumper wire from the system neutral to all the branch neutrals one at a time to find the sparky one. Then I joined em up and read the 4-1/2 amps with my fluke t-whatever it is number that has the amp slot.


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## HackWork (Oct 2, 2009)

A tick tracer will pickup a hot neutral after it has been disconnected from the grounded source, right?

As far as using an amp clamp to test for current flowing, the meter would have to measure down to 50mA since that is what can kill you. Does the T5 or other common amp probes measure down that low?


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## VELOCI3 (Aug 15, 2019)

If they only new what we go through they would stop making movies about cops and firefighters being heroes...


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## MTW (Aug 28, 2013)

The Fluke one does, Mikey. It's all I use.


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## gpop (May 14, 2018)

In industrial so many wires can light your arse up when disconnected that the rules are simple. If its not grounded its hot. 

Couple of wraps of 33 can be your best friend.


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## macmikeman (Jan 23, 2007)

MTW said:


> The Fluke one does, Mikey. It's all I use.


Try testing that just to prove it . Hold it next to the neutral bus, away from any hot wires, take a picture to show the light is clearly on. Oh and no reversing the panel polarity just to get a good picture.:wink:


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## MTW (Aug 28, 2013)

macmikeman said:


> Try testing that just to prove it . Hold it next to the neutral bus, away from any hot wires, take a picture to show the light is clearly on. Oh and no reversing the panel polarity just to get a good picture.:wink:


If you disconnect the neutral wire from the bus bar and it's a live circuit with a load on it, it will definitely detect it.


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## macmikeman (Jan 23, 2007)

MTW said:


> If you disconnect the neutral wire from the bus bar and it's a live circuit with a load on it, it will definitely detect it.


Yes, so will mine. But mine won't while connected to the bus it won't, which is what happened during my event. Nothing lit up while it was connected so I proceeded to start demo. Did you read it at all? Once I pulled the neutral return out of the lug, I lit up instead of the little volt ticker device. This thread is about a warning to check for amp flow on that return before opening the circuit. Not to argue about what brand of volt tic is the best. If your fluke device shows current flow , with the neutral still in place and carrying the load, demonstrate it to us so we can all presently rush out to get one. It would be less of a hassle then reaching over to my husky bag to get out the t-x fluke volt tester . I have the new one with the bigger slot to read all the way up to 3/0. Two or three working clamps in the van, and ... a flexible really larger additional accessory amp clamp that will encircle any conductor they make.


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## MTW (Aug 28, 2013)

macmikeman said:


> Yes, so will mine. But mine won't while connected to the bus it won't, which is what happened during my event. Nothing lit up while it was connected so I proceeded to start demo. Did you read it at all? Once I pulled the neutral return out of the lug, I lit up instead of the little volt ticker device.


I'm saying that in that situation, simply checking the main neutral with your ticker would have detected it was live once disconnected from the lug.


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## macmikeman (Jan 23, 2007)

MTW said:


> I'm saying that in that situation, simply checking the main neutral with your ticker would have detected it was live once disconnected from the lug.


Ok I get it , except that be-otch required a whole lot of struggle to get it loose from the lug and my fingers ended up on the bare part when it did come loose. 
I shoulda had gloves on is what I shoulda had. Putting that aside, check the stupid neutral before pulling it out of the lugs and save yourself a potential potential...... Hey! my new tag line!


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## macmikeman (Jan 23, 2007)

HackWork said:


> A tick tracer will pickup a hot neutral after it has been disconnected from the grounded source, right?
> 
> *As far as using an amp clamp to test for current flowing, the meter would have to measure down to 50mA since that is what can kill you. Does the T5 or other common amp probes measure down that low?*


No they don't. But skin resistance comes into play here. I'm writing this reply right now , after passing current thru arm to arm. The rated current was 4.5 amps. I'm fairly certain I didn't take the full load or else I would have keeled over. P.S. I get shocks sorta about once every few months, have my whole life. I'm not endorsing them , just saying what a rootin tootin leather rough mean ornery cuss I really am . I am to tough what Hax is to handsome...... :vs_cool:


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## HackWork (Oct 2, 2009)

macmikeman said:


> No they don't. But skin resistance comes into play here. I'm writing this reply right now , after passing current thru arm to arm. The rated current was 4.5 amps. I'm fairly certain I didn't take the full load or else I would have keeled over. P.S. I get shocks sorta about once every few months, have my whole life. I'm not endorsing them , just saying what a rootin tootin leather rough mean ornery cuss I really am . I am to tough what Hax is to handsome...... :vs_cool:


Your situation was 4.5 amps flowing thru the circuit. But there could have only been 100mA of current flowing thru it. 

If you had tested it with your amp clamp first, it would not register that and you would think it was dead. But then you would have gotten shocked when touching it just the same as you did today. And that 100mA is enough to kill you.

I'm just saying that even using the amp clamp wont protect you in all situations, you can still get zapped.


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## splatz (May 23, 2015)

HackWork said:


> Your situation was 4.5 amps flowing thru the circuit. But there could have only been 100mA of current flowing thru it.
> 
> If you had tested it with your amp clamp first, it would not register that and you would think it was dead. But then you would have gotten shocked when touching it just the same as you did today. And that 100mA is enough to kill you.
> 
> I'm just saying that even using the amp clamp wont protect you in all situations, you can still get zapped.


Wait I follow but I believe there is a flaw in your logic. 

If there is 100ma flowing through that neutral wire, there is a pretty high resistance resistor upstream. If you put another high resistance resistor in series, it will no longer be 100ma flowing through it. (Your body is that second high resistance resistor.) 

It is of course voltage that determines what will flow through that resistor. So what's the voltage? 

If 4.5 amps is flowing on the neutral in a 120V L-N circuit, the load is 26.7 ohms. With @macmikeman taking it hand to hand, it becomes a series circuit. I forget the resistance of the body but you could look it up and calculate it. 

You could figure out what amperage would see with low enough resistance that 30ma will still flow with you taking it hand to hand.


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## HackWork (Oct 2, 2009)

I'm not sure what you are saying.

What I am saying is that a typical amp clamp might not register a small amount of current flowing, while that small amount might still be enough to kill you.

I see Mikey's signature says:


> Check the stupid neutral with an amp probe before pulling it out of the lugs and save yourself a potential potential......


 This makes me think that checking it with an amp clamp would prove that it's dead and allow someone to touch it safely. Is that true? Can't there still be enough current flowing to kill someone?


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## splatz (May 23, 2015)

HackWork said:


> I'm not sure what you are saying.
> 
> What I am saying is that a typical amp clamp might not register a small amount of current flowing, while that small amount might still be enough to kill you.
> 
> ...


If the circuit starts like this 

120V L1 --------/\/\/ R1 \/\/\------------N 

Now if you add a big resistor 

120V L1 --------/\/\/ R1 \/\/\-------/\/\/ macmikeman \/\/\-----N 

The circuit has much more resistance and so less current. The voltage across the macmikeman resistor is not 120, it already dropped across R1. 

Its a little more complicated because you have the neutral carrying the imbalance between two legs but I think the outcome is the same.


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## HackWork (Oct 2, 2009)

I still don't know what you are saying.

Are you saying that if the amount of current flowing is less than the typical amp probe's resolution, that it won't be enough to hurt or kill someone?


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## splatz (May 23, 2015)

HackWork said:


> I still don't know what you are saying.
> 
> Are you saying that if the amount of current flowing is less than the typical amp probe's resolution, that it won't be enough to hurt or kill someone?


My point is just that the current flowing on the neutral is not the current you're going to get shocked with. If you see 100ma on the neutral you're not going to get shocked with 100ma, it will be something less. 

Your point may still be 100% correct - an amp clamp may not be sensitive enough to determine whether it's safe to touch - and you could calculate it, but you'll need a number for the resistance of the body to figure it out. And the specs for the amp clamp.


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## HackWork (Oct 2, 2009)

splatz said:


> My point is just that the current flowing on the neutral is not the current you're going to get shocked with. If you see 100ma on the neutral you're not going to get shocked with 100ma, it will be something less.


 Like 50mA, which is enough to kill someone.

You'll never know the resistance of the person's body because it is so variable, including what they ate the day before and how much they are perspiring at that exact second. So we can't stand on mathematical equations to determine if it's safe to touch it or not. I think we should just say NO, an amp probe showing 0 current flow does not mean it's safe to touch. Just my opinion.


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## splatz (May 23, 2015)

HackWork said:


> Like 50mA, which is enough to kill someone.
> 
> You'll never know the resistance of the person's body because it is so variable, including what they ate the day before and how much they are perspiring at that exact second. So we can't stand on mathematical equations to determine if it's safe to touch it or not. I think we should just say NO, an amp probe showing 0 current flow does not mean it's safe to touch. Just my opinion.


The resistance of the body is of course highly variable but there may be some conservative number at the low end of the possible range that you could use to make a calculation. I wouldn't rule it out. 

But I agree, it's safer to just not touch it. 

Still doesn't hurt to check with a clamp meter - it's still good information and realistically switches you from "do it to be safe" mode to "SOMETHING'S VERY WRONG HERE" mode. Just don't consider a zero reading safe.


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## splatz (May 23, 2015)

Now I am just spitballing but along with the easy checks, including amp clamping the neutrals, what's the best thing to do? Work as if hot, and check voltage to ground on each wire as you disconnect them?


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## HackWork (Oct 2, 2009)

splatz said:


> Now I am just spitballing but along with the easy checks, including amp clamping the neutrals, what's the best thing to do? Work as if hot, and check voltage to ground on each wire as you disconnect them?


I generally snip all the neutrals off the neutral bar with *****. This is where a tick tracer will show if one is hot.


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## Going_Commando (Oct 1, 2011)

I got a similar one last Friday Mike. Only it was when I cut a #14 ground wire that somehow became the neutral for a panel with a bad nuetral lug in the meter socket. Got it across the heart path and my lights went out in the basement. Not pleasant. Was probably similar amperage.


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## macmikeman (Jan 23, 2007)

Going_Commando said:


> I got a similar one last Friday Mike. Only it was when I cut a #14 ground wire that somehow became the neutral for a panel with a bad nuetral lug in the meter socket. Got it across the heart path and my lights went out in the basement. Not pleasant. Was probably similar amperage.


Probably less due to less fixtures , but I could be wrong as hell. How many lights were on? Either way it hurts a bit for a second right?


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## macmikeman (Jan 23, 2007)

HackWork said:


> Like 50mA, which is enough to kill someone.
> 
> You'll never know the resistance of the person's body because it is so variable, including what they ate the day before and how much they are perspiring at that exact second. So we can't stand on mathematical equations to determine if it's safe to touch it or not. I think we should just say NO, an amp probe showing 0 current flow does not mean it's safe to touch. Just my opinion.


You are probably on to something here. I'll probably have to change my signature............ 

I don't think those Fluke t-pro's and their sisters register down below .5 maybe not even that far.....


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## emtnut (Mar 1, 2015)

macmikeman said:


> I get shocks sorta about once every few months, have my whole life.



Soooooo ... Answer the ago old question !
Does the neutral shock kick more than a hot shock ?? :biggrin:


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