# Electrical Mystery Theater2020



## splatz (May 23, 2015)

Neutral issue, maybe with their service, maybe with the neighbors.


----------



## nrp3 (Jan 24, 2009)

Where's the talking robots?


----------



## CoolWill (Jan 5, 2019)

The grounded coax sheath was carrying neutral current. Did I win?


----------



## VELOCI3 (Aug 15, 2019)

Old building. This is the third time I’ve seen this happen. First time was bad neutral splice in the service drop. Second was a partial break in the overhead service lateral. This one I will see what I can find. 


Sent from my iPhone using Tapatalk


----------



## VELOCI3 (Aug 15, 2019)

CoolWill said:


> The grounded coax sheath was carrying neutral current. Did I win?




I would say yes since the coax uses the same ground as the XFMR on the pole for XO


Sent from my iPhone using Tapatalk


----------



## five.five-six (Apr 9, 2013)

You could actually get killed connecting your cable box


Amazing.


----------



## joe-nwt (Mar 28, 2019)

The only way that should happen is if the cable box was connected to one cct and the TV connected to another. Am I wrong with that line of thinking?

Or is the break in the neutral right at the tab on the receptacle?


----------



## joe-nwt (Mar 28, 2019)

After thinking about it, how would a coax shield be connected to the neutral in the first place?


----------



## VELOCI3 (Aug 15, 2019)

joe-nwt said:


> After thinking about it, how would a coax shield be connected to the neutral in the first place?




At the pole


Sent from my iPhone using Tapatalk


----------



## VELOCI3 (Aug 15, 2019)

In this case the shield is a lower resistive path back to the Transformer XO on the pole


Sent from my iPhone using Tapatalk


----------



## joe-nwt (Mar 28, 2019)

VELOCI3 said:


> At the pole
> 
> 
> Sent from my iPhone using Tapatalk


I got that. There needs to be a second connection for current. Where would that be?


----------



## nrp3 (Jan 24, 2009)

More often than not, there's a connection at the service somewhere, bond bridge, meter socket, etc.


----------



## VELOCI3 (Aug 15, 2019)

joe-nwt said:


> I got that. There needs to be a second connection for current. Where would that be?




If the neutral is floating in your panel or the connection is more resistive than the direct line back to your power source it will take that path. 

Had a 240V 1PH 200 amp service with hot to the touch breakers and 30 amps going through the cable TV coax going to the pole. Problem was corroded neutral splice at the service drop. 


Sent from my iPhone using Tapatalk


----------



## joe-nwt (Mar 28, 2019)

Maybe I'm not awake yet this Sunday morning but where would the second connection to the coax in the picture? That isn't the entrance coax in the picture. Where is the second connection in the house? 

The coax in the picture looks like a short piece between equipment in the house?


----------



## five.five-six (Apr 9, 2013)

joe-nwt said:


> After thinking about it, how would a coax shield be connected to the neutral in the first place?



Generally at the MPOE/Dmark there is a bonding coupler that’s bonded to #10 or at least #12. Also, the coax splitter/amp (pole or underground) is grounded and connected to several other residences through the shield.


----------



## joe-nwt (Mar 28, 2019)

five.five-six said:


> Generally at the MPOE/Dmark there is a bonding coupler that’s bonded to #10 or at least #12. Also, the coax splitter/amp (pole or underground) is grounded and connected to several other residences through the shield.


I got that too. But the short interior piece in the photo would be completely inside the house past the typical shield ground at the service. It would have to be connected to the neutral again somewhere in the house for that to happen, no? How could it be connected again is my question.


----------



## CoolWill (Jan 5, 2019)

joe-nwt said:


> Maybe I'm not awake yet this Sunday morning but where would the second connection to the coax in the picture? That isn't the entrance coax in the picture. Where is the second connection in the house?
> 
> The coax in the picture looks like a short piece between equipment in the house?


The neutral is open so the main bonding jumper will carry the current over to the ground bus and down any grounding conductor that has a path back to the transformer. The TV or cable box has a ground on its plug. Neutral current comes out of the ground at the receptacle, into the cable box and onto the coax which leads back to the pole.


----------



## telsa (May 22, 2015)

TV is dangerous to your health. So too, the Internet.


----------



## joe-nwt (Mar 28, 2019)

CoolWill said:


> The neutral is open so the main bonding jumper will carry the current over to the ground bus and down any grounding conductor that has a path back to the transformer. The TV or cable box has a ground on its plug. Neutral current comes out of the ground at the receptacle, into the cable box and onto the coax which leads back to the pole.


So you are saying the coax shield is grounded to the neutral in the cable box?


----------



## CoolWill (Jan 5, 2019)

joe-nwt said:


> So you are saying the coax shield is grounded to the neutral in the cable box?


No. I'm saying the coax is grounded to the ground pin of the cord, which is connected to the receptacle ground which is connected to the neutral at the main.


----------



## joe-nwt (Mar 28, 2019)

CoolWill said:


> No. I'm saying the coax is grounded to the ground pin of the cord, which is connected to the receptacle ground which is connected to the neutral at the main.



I get that. So where is the current, neutral current seems to be the popular consensus, coming from? Even if there is a neutral problem somewhere in the house, the coax shield still has to be (connected to neutral) at 2 places in the house for current to flow. One is the shield ground at the service/demarcation, where could the other be?

Maybe I need another coffee.....

edit for clarity


----------



## CoolWill (Jan 5, 2019)

joe-nwt said:


> I get that. So where is the current, neutral current seems to be the popular consensus, coming from? Even if there is a neutral problem somewhere in the house, the coax shield still has to be (connected to neutral) at 2 places in the house for current to flow. One is the shield ground at the service/demarcation, where could the other be?
> 
> Maybe I need another coffee.....
> 
> edit for clarity


One end of the coax is connected to the neutral at the pole. The other end is connected to the ground inside the house, which is connected to the neutral at the service, which is open ahead of that. The neutral current is from every circuit in the house.

The neutral current is crossing the main bonding jumper and traveling down the equipment ground to the cable box and back to the transformer through the coax.


----------



## VELOCI3 (Aug 15, 2019)

joe-nwt said:


> I get that. So where is the current, neutral current seems to be the popular consensus, coming from? Even if there is a neutral problem somewhere in the house, the coax shield still has to be (connected to neutral) at 2 places in the house for current to flow. One is the shield ground at the service/demarcation, where could the other be?
> 
> Maybe I need another coffee.....
> 
> edit for clarity




There must be a bonded transformer inside the cable box 


Sent from my iPhone using Tapatalk


----------



## five.five-six (Apr 9, 2013)

joe-nwt said:


> I got that too. But the short interior piece in the photo would be completely inside the house past the typical shield ground at the service. It would have to be connected to the neutral again somewhere in the house for that to happen, no? How could it be connected again is my question.


Ground provided by coax shield > ground blade cable box power cord > main ground bar > main neutral bar


----------



## joe-nwt (Mar 28, 2019)

five.five-six said:


> Ground provided by coax shield > ground blade cable box power cord > main ground bar > main neutral bar


Not to be rude but quit explaining the path of the ground inside the house please.

The coax shield is bonded to the neutral at the service and thus the neutral, I get that. But before neutral current can flow on the coax shield INSIDE the residence, it has to be bonded to the neutral at another point. WHERE COULD THIS BE?

That is my question, perhaps I haven't been asking clearly enough?


----------



## joe-nwt (Mar 28, 2019)

VELOCI3 said:


> There must be a bonded transformer inside the cable box
> 
> 
> Sent from my iPhone using Tapatalk


I would be surprised if the same people that forbid the bonding of ground and neutral at any point other than the service would certify this equipment.


----------



## VELOCI3 (Aug 15, 2019)

joe-nwt said:


> Not to be rude but quit explaining the path of the ground inside the house please.
> 
> 
> 
> ...




Scroll up for a potential answer


Sent from my iPhone using Tapatalk


----------



## joe-nwt (Mar 28, 2019)

Scroll down for my potential reply.


----------



## mofos be cray (Nov 14, 2016)

Correct me if I'm wrong but the proposed cause is a high resistance fault in the neutral main feed to the apt. Then, because the neutral is bonded to ground at the main panel and the coax is bonded to ground to ground the neutral current travels from the end of use device back to the panel. Then, encountering the high resistance back to the source passes through the bonding jumper to the coax bond and back through the coax to the xo of the tx where the coax is grounded as well.
There seems to be more to this parallel path thing than I thought.


----------



## CoolWill (Jan 5, 2019)

joe-nwt said:


> Not to be rude but quit explaining the path of the ground inside the house please.
> 
> The coax shield is bonded to the neutral at the service and thus the neutral, I get that. But before neutral current can flow on the coax shield INSIDE the residence, it has to be bonded to the neutral at another point. WHERE COULD THIS BE?
> 
> That is my question, perhaps I haven't been asking clearly enough?


No. It was clear. You just aren't picturing the whole setup.


----------



## telsa (May 22, 2015)

CoolWill said:


> No. It was clear. You just aren't picturing the whole setup.


That's a head-turner if I've ever seen one. :biggrin:


----------



## emtnut (Mar 1, 2015)

joe-nwt said:


> The coax shield is bonded to the neutral at the service and thus the neutral, I get that. But before neutral current can flow on the coax shield INSIDE the residence, it has to be bonded to the neutral at another point. WHERE COULD THIS BE?





joe-nwt said:


> I would be surprised if the same people that forbid the bonding of ground and neutral at any point other than the service would certify this equipment.


Valid question.
If the cable box is a metal box, then it would have a 3 prong cord, and the ground should not be connected to neutral (shouldn't be, but I can't vouch for chinese crap that's up here)
Chances are, it's a plastic box with a 2 prong wall-wart. The neutral on the wall-wart is connected to the shield on the co-ax ... and that's the completed circuit you were looking for.


----------



## readydave8 (Sep 20, 2009)

at main where neutral is bonded to ground

electrons having trouble going the way they're supposed to

so one available path is bare ground back to tv, from case of tv to coax shield, and from there to where shield is bonded to ground

(as others have said)


----------



## five.five-six (Apr 9, 2013)

joe-nwt said:


> Not to be rude but quit explaining the path of the ground inside the house please.



No ..


----------



## five.five-six (Apr 9, 2013)

joe-nwt said:


> Scroll down for my potential reply.



perhaps you’d be better suited as a plumber.


----------



## VELOCI3 (Aug 15, 2019)

emtnut said:


> Valid question.
> If the cable box is a metal box, then it would have a 3 prong cord, and the ground should not be connected to neutral (shouldn't be, but I can't vouch for chinese crap that's up here)
> Chances are, it's a plastic box with a 2 prong wall-wart. The neutral on the wall-wart is connected to the shield on the co-ax ... and that's the completed circuit you were looking for.




Cable vision box. 2 wire portable radio type cable


Sent from my iPhone using Tapatalk


----------



## A Little Short (Nov 11, 2010)

joe-nwt said:


> Not to be rude but quit explaining the path of the ground inside the house please.
> 
> The coax shield is bonded to the neutral at the service and thus the neutral, I get that. But before neutral current can flow on the coax shield INSIDE the residence, it has to be bonded to the neutral at another point. WHERE COULD THIS BE?
> 
> That is my question, perhaps I haven't been asking clearly enough?



Let's see if I can be clear enough!


THE NEUTRAL IS OPEN/BROKEN SOMEWHERE, THE NEUTRAL PATH IS USING THE GROUND BACK TO IT'S SOURCE!


----------



## joe-nwt (Mar 28, 2019)

CoolWill said:


> No. It was clear. You just aren't picturing the whole setup.


Nice picture. Thanks again for showing me the ground/neutral path in a common residence. I was completely in the dark about that.......


Lets start at the beginning, shall we? For all the plumbers on this forum.



VELOCI3 said:


> Lady: “so I had a small fire in my apartment with my cable wire


The coax in the picture is NOT the drop from the pole. It is the cable from the box to the TV/DVR/whatever. For current to flow on that coax shield, it would have to be connected to the neutral somewhere other than the bond at the panel.

Where?


----------



## CoolWill (Jan 5, 2019)

joe-nwt said:


> Nice picture. Thanks again for showing me the ground/neutral path in a common residence. I was completely in the dark about that.......
> 
> 
> Lets start at the beginning, shall we? For all the plumbers on this forum.
> ...


Fuq you buddy. Don't get pissy with me because you don't get it. It doesn't matter how many devices you chain together with coax, all the shields are connected together and back to the cable drop. And if a grounding conductor supplies ANY of that equipment, the shield will be connected to that too. My TV has a 3 prong cord, but the cable box didnt. Connecting them with coax meant that the whole chain of coax was connected to the circuit ground.


----------



## MikeFL (Apr 16, 2016)

Haven't read the entire thread but I did see the beginning. Open noodle.

Had a call last week from a friend who lives on a boat (common down here). Says his engine block heater wiring was smoking. Told him to disconnect shore power. Asked him to read L-L and L1-N and L2-N at the shore power connector and he didn't understand. I went down there and found 244V L-L and 98V L1-N and 102V L2-N. Told him to tell the marina they need an electrician to fix an open neutral. Apparently their "electrician" is the guy who dumps trash and cleans restrooms. Not sure what ever came of it. Wonder how many of those boats will catch fire before they fix it. And yes, I did ask why he has an engine block heater in south Florida. He says it makes the diesel engine start better.


----------



## joe-nwt (Mar 28, 2019)

CoolWill said:


> Fuq you buddy. Don't get pissy with me because you don't get it. It doesn't matter how many devices you chain together with coax, all the shields are connected together and back to the cable drop. And if a grounding conductor supplies ANY of that equipment, the shield will be connected to that too. My TV has a 3 prong cord, but the cable box didnt. Connecting them with coax meant that the whole chain of coax was connected to the circuit ground.



Thanks for once again explaining the ground path. 

I am not getting pissy. I consider this a complete failure on my part so far for not getting my question out there for all to understand. Although I'm pretty sure VELOCI3 and emtnut understood what I was asking.

So instead of resorting to name calling and whatnot, I am going to give it one more try.

I understand the ground path, how it is connected to the neutral at both the service and the xfmr. Why the current, once on the coax shield, would take whatever path to get back to the source. I get all that.

Sooooo, how did the neutral current get on the shield in the first place? Where is that connection inside the residence?

If that is not clear enough, you win and I fail.


----------



## dronai (Apr 11, 2011)

Where is the bond from ground to neutral inside the house ? Maybe someone tied that together somewhere inside the house, now you have a path.


----------



## joe-nwt (Mar 28, 2019)

dronai said:


> Where is the bond from ground to neutral inside the house ? Maybe someone tied that together somewhere inside the house, now you have a path.


Could be. But that doesn't explain how the neutral current get onto the coax shield inside the house.


----------



## dronai (Apr 11, 2011)

joe-nwt said:


> Could be. But that doesn't explain how the neutral current get onto the coax shield inside the house.


Maybe the Cable box shorted


----------



## CoolWill (Jan 5, 2019)

joe-nwt said:


> Thanks for once again explaining the ground path.
> 
> I am not getting pissy. I consider this a complete failure on my part so far for not getting my question out there for all to understand. Although I'm pretty sure VELOCI3 and emtnut understood what I was asking.
> 
> ...


At the risk of you bleeding out of your ears over the ground path, I will say look at the picture I posted, even though it's upside down.

With the service neutral open, the ground bus becomes energized because of the bonding jumper at the main. I know you're with me so far. Every ground prong of every receptacle in the house will have voltage on it because it is in series with the neutrals of all the 120 volt loads. The neutral current on the coax is COMING OUT of the ground prong and into a TV or cable box and from there to the coax.

Look at the pic. The thick black line. The light bulb represents 120 volt loads energizing the ground bus through the white wire. Don't give up yet. We're almost there.


----------



## CoolWill (Jan 5, 2019)

Granted, if no devices that are connected to the coax have 3 prong cords, then it can't happen the way I'm saying.


----------



## joe-nwt (Mar 28, 2019)

Alright! I understand what you are saying! Having never seen a 3 prong cable box I had no idea what you were trying to say. Yes, if there is grounded cable boxes then it would be definitely possible. 

Its all good.:vs_cool:


----------



## splatz (May 23, 2015)

joe-nwt said:


> Alright! I understand what you are saying! Having never seen a 3 prong cable box I had no idea what you were trying to say. Yes, if there is grounded cable boxes then it would be definitely possible.
> 
> Its all good.:vs_cool:


 Even if the cable box is two wire, there is usually a grounding block at the service entrance for the cable 













Then there's a wire from the ground lug on this block to the intersystem grounding bridge or etc. but the shield of the coax should be grounded.


----------



## dronai (Apr 11, 2011)

In my experience, with an open neutral from the utility, the voltage will be high on one phase, and low on another. unless there is a ground connected to a neutral in the building, there is no path ?


----------



## splatz (May 23, 2015)

dronai said:


> In my experience, with an open neutral from the utility, the voltage will be high on one phase, and low on another. unless there is a ground connected to a neutral in the building, there is no path ?


 The neutral lug on the utility transformer is bonded to the utility ground rod, the neutral lug at the service is bonded to the EGC, the ground itself is a path. 



If the water pipe is metallic you can picture how there well might be current on the neighbor's ground as well. 



The coax shield is in the ground path, much lower resistance than the dirt, and may be bonded to the neighbor's coax shield at the cable company's amplifier on the pole ...


----------



## emtnut (Mar 1, 2015)

VELOCI3 said:


> There must be a bonded transformer inside the cable box





splatz said:


> Even if the cable box is two wire, there is usually a grounding block at the service entrance for the cable
> 
> Then there's a wire from the ground lug on this block to the intersystem grounding bridge or etc. but the shield of the coax should be grounded.



Unless I'm missing something, that says that the shield at the cable box is tied to the neutral on the power supply. 

So with 2 or 3 prong cord, either way there is a parallel path possible with an open neutral.


----------



## VELOCI3 (Aug 15, 2019)

So I looked today. Panel in lady’s APT is a 60 amp 208V. 
A ph- 2 amps
B ph-2.5 amps
N- 2.1 amps

Coax had no amperage. Not sure where the excess neutral current is coming from. 

Building service is 400A 3ph 4W 208V 

Overhead service is 600MCM
POCO has #4 quadplex feeding it
Mid span POCO splices look very very old. 

Main disco









There are 25 apartments and the lights randomly flicker and dim in all the units. Getting worse over the past 12 months.


Gonna put in a ticket for POCO to check their taps and address the overhead size issue


Sent from my iPhone using Tapatalk


----------



## MikeFL (Apr 16, 2016)

VELOCI3 said:


> Lady: “so I had a small fire in my apartment with my cable wire and the FD said I should contact an electrician can you come by to check my outlets and electric panel?”
> 
> Me: “can elaborate on your concerns over your outlets and panel?”
> 
> ...


2 questions on that picture:

1. Any way to find out if it happened suddenly or over a period of time?
2. Was it bent/ jammed up against something when it was discovered like that? Or did that happen to it as someone removed it/ disconnected it in a panic?


----------



## VELOCI3 (Aug 15, 2019)

MikeFL said:


> 2 questions on that picture:
> 
> 
> 
> ...




She seemed to think it was sudden. She said it was smoking and glowing and when she moved the cable box sparks went everywhere. Cable box was cleared ok by the cable company. 




Sent from my iPad using Tapatalk


----------



## readydave8 (Sep 20, 2009)

joe-nwt said:


> Thanks for once again explaining the ground path.
> 
> I am not getting pissy. I consider this a complete failure on my part so far for not getting my question out there for all to understand. Although I'm pretty sure VELOCI3 and emtnut understood what I was asking.
> 
> ...


What'd I miss with my graphic answer?

post 34


----------



## readydave8 (Sep 20, 2009)

dronai said:


> Where is the bond from ground to neutral inside the house ? Maybe someone tied that together somewhere inside the house, now you have a path.


no only tied together at main disconnect where neutral is bonded to ground


----------



## VELOCI3 (Aug 15, 2019)

dronai said:


> In my experience, with an open neutral from the utility, the voltage will be high on one phase, and low on another. unless there is a ground connected to a neutral in the building, there is no path ?




The ground is only for fault current. If you lift the main neutral even though there is a good ground the voltage will be all over the place (even the way you described it). The neutral load wants to get back to its source to balance out. Most cases it’s the one ground rod at the utility transformer bonded to XO


Sent from my iPhone using Tapatalk


----------



## dronai (Apr 11, 2011)

VELOCI3 said:


> The ground is only for fault current. If you lift the main neutral even though there is a good ground the voltage will be all over the place (even the way you described it). The neutral load wants to get back to its source to balance out. Most cases it’s the one ground rod at the utility transformer bonded to XO
> 
> 
> Sent from my iPhone using Tapatalk


Yes, but I'm confused with Joe, where the shield is getting the hot from ? Is the center of the coax the hot, and now


----------



## VELOCI3 (Aug 15, 2019)

dronai said:


> Yes, but I'm confused with Joe, where the shield is getting the hot from ? Is the center of the coax the hot, and now




Center of the coax is hot from a different system. It comes in from the cable company. The shield is becoming a pathway for the building neutral and because it’s not designed for that it overheats til it or the load clears


Sent from my iPhone using Tapatalk


----------



## dronai (Apr 11, 2011)

VELOCI3 said:


> Center of the coax is hot from a different system. It comes in from the cable company. The shield is becoming a pathway for the building neutral and because it’s not designed for that it overheats til it or the load clears
> 
> 
> Sent from my iPhone using Tapatalk


I see it now. The only path back to the source is through that coax. So power would loop through the panel neutral ground bond, and back in the house through the Ground wire, to the only neutral avaliable, the shield ground/neutral wire.:vs_clap:


----------



## splatz (May 23, 2015)

VELOCI3 said:


> So I looked today. Panel in lady’s APT is a 60 amp 208V.
> A ph- 2 amps
> B ph-2.5 amps
> N- 2.1 amps
> ...


I am guessing another customer on the same transformer.


----------



## LARMGUY (Aug 22, 2010)




----------



## joebanana (Dec 21, 2010)

joe-nwt said:


> Not to be rude but quit explaining the path of the ground inside the house please.
> 
> The coax shield is bonded to the neutral at the service and thus the neutral, I get that. But before neutral current can flow on the coax shield INSIDE the residence, it has to be bonded to the neutral at another point. WHERE COULD THIS BE?
> 
> That is my question, perhaps I haven't been asking clearly enough?


Through any load. The cable box? The TV? The DVD? Are we sure there's a MBJ at the panel?


----------



## VELOCI3 (Aug 15, 2019)

Sent from my iPad using Tapatalk


----------



## VELOCI3 (Aug 15, 2019)

Sent from my iPad using Tapatalk


----------



## nrp3 (Jan 24, 2009)

VELOCI3 said:


> Sent from my iPad using Tapatalk


Something looks like its seen better days...:sad:


----------



## VELOCI3 (Aug 15, 2019)

Update. After getting the POCO to re-splice the service connections on their overhead the issue has been resolved. 


Sent from my iPhone using Tapatalk


----------



## Easy (Oct 18, 2017)

CoolWill said:


> At the risk of you bleeding out of your ears over the ground path, I will say look at the picture I posted, even though it's upside down.
> 
> With the service neutral open, the ground bus becomes energized because of the bonding jumper at the main. I know you're with me so far. Every ground prong of every receptacle in the house will have voltage on it because it is in series with the neutrals of all the 120 volt loads. The neutral current on the coax is COMING OUT of the ground prong and into a TV or cable box and from there to the coax.
> 
> Look at the pic. The thick black line. The light bulb represents 120 volt loads energizing the ground bus through the white wire. Don't give up yet. We're almost there.


Great job explaining this. Basically your just saying that with an open neutral the current looked for another path. Any path.. The coax shielding just happened to be a path of no return. :smile:


----------

