Bad Neutral?

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the worker wasnt killed, he was shocked pretty bad though, his buddy raced in the house and shut off the main, saying the homeowner could've killed his partner. Got the homeowner all in a fuss, worried his house was a danger to others. I just get a kick how so many people, even ones so close to our industry, being ignorant to the physics of our trade. Today I get the problem solved.
 
Praedatus1 said:
the worker wasnt killed, he was shocked pretty bad though, his buddy raced in the house and shut off the main, saying the homeowner could've killed his partner. Got the homeowner all in a fuss, worried his house was a danger to others. I just get a kick how so many people, even ones so close to our industry, being ignorant to the physics of our trade. Today I get the problem solved.
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Regardless of why this neutral got damaged,it deserved 911 attention.Only real issue here is who owns that run of wire from meter to transformer.Usually its the poco.
 
brother said:
This is why i hear that some plumbers/pipefitters, want to change the NEC with the using the water pipe to the house as a GEC. They sometimes have to change them to plastic when repairing and they get shocked.

So what do you think of the NEC changing the water pipe from being used as the GEC?? Making people use more ground rods or ring or plates as the GEC.
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Do you mean no longer connecting to the water line like this picture shows? Do you think that will eliminate the current flow on the water line?:
BrokenNeutral.jpg
 
mivey said:
Do you mean no longer connecting to the water line like this picture shows? Do you think that will eliminate the current flow on the water line?:
BrokenNeutral.jpg
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Draw in the rest of the picture.2 houses on same transformer.Not exact the same anymore.2nd house was the neutral for the first via the pipe.
 
Praedatus1 said:
the worker wasnt killed, he was shocked pretty bad though, his buddy raced in the house and shut off the main, saying the homeowner could've killed his partner. Got the homeowner all in a fuss, worried his house was a danger to others. I just get a kick how so many people, even ones so close to our industry, being ignorant to the physics of our trade. Today I get the problem solved.
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Had a customer all in arms that a plumber working on a house next door messed up his electrical - didn't care that he to got shocked in the process - was actually thinking to sue the guy until I had (and taken some serious time) to explain it to him....

I tell plumbers to jumper water mains when they cut them anyway - as they are often cutting the electrode temporarily - regardless of this type of current/shock hazard. If they know nothing else about electrical they should know that IMO.
 
e57 said:
Had a customer all in arms that a plumber working on a house next door messed up his electrical - didn't care that he to got shocked in the process - was actually thinking to sue the guy until I had (and taken some serious time) to explain it to him....

I tell plumbers to jumper water mains when they cut them anyway - as they are often cutting the electrode temporarily - regardless of this type of current/shock hazard. If they know nothing else about electrical they should know that IMO.
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A lot of time they put in Dielectric unions and there goes the GE.
Sounds like the Nuetral is gone.
I've seen folks in that area direct bury a triplex ,,, How long ya think that will last.

How about meggering the wire if they PG&E does not believe you.. Make sure the wires are dead first.
 
brother said:
This is why i hear that some plumbers/pipefitters, want to change the NEC with the using the water pipe to the house as a GEC. They sometimes have to change them to plastic when repairing and they get shocked.

So what do you think of the NEC changing the water pipe from being used as the GEC?? Making people use more ground rods or ring or plates as the GEC.
Click to expand...

With all metal plumbing.....

If you eliminate the water line as a GEC, you would also have to eliminate bonding the interior plumbing and the equipment ground for the water heater.

All of those are paths back to the underground plumbing.

It could be a real problem if the service neutral was open and the only path back to the transformer was the #10cu water heater grounding conductor.

steve
 
hillbilly said:
With all metal plumbing.....

If you eliminate the water line as a GEC, you would also have to eliminate bonding the interior plumbing and the equipment ground for the water heater.

All of those are paths back to the underground plumbing.

It could be a real problem if the service neutral was open and the only path back to the transformer was the #10cu water heater grounding conductor.

steve
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Hey guys, thought I'd wait a while to chime in.

I've been studying up on Mike Holts video training series. The one on Art. 250 has a couple of videos at the end of it that are directly related to this. One is a 'video investigation' by a Fire Marshal in Florida. The house they were documenting burned down; they pulled the meter but still had an arc inside the wall because it was the neutral from the neighbor's house that went bad.

It's reasons like this that Mike suggests bonding the service at the transformer (on the utility side) and not at the house. Instead of triplex all services would be quadraplex (sp?). The more I hear of these situations the more I tend to agree. Will it happen? Probably not.

Praedatus1-You have a lot of explaining to do to the powers that be. Good luck. My only advice: try not to get too upset when they don't understand.

Thanks to the rest of you guys I'm still learning a lot about neutrals.
 
hillbilly said:
With all metal plumbing.....

If you eliminate the water line as a GEC, you would also have to eliminate bonding the interior plumbing and the equipment ground for the water heater.

All of those are paths back to the underground plumbing.

It could be a real problem if the service neutral was open and the only path back to the transformer was the #10cu water heater grounding conductor.

steve
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Im not talking about getting rid of the bonding, im just talking about not using it as the GEC. I know what you saying, but wouldnt there be less resistance on just using another electrode? We have use a #4 on the water pipe here and #6 on the rods. I always felt that the water pipe bond should be no more than a #10, and rods should have the bigger wire for the GEC. its not much but it would help.

Maybe we should just do a 4 wire from the transformer and just have the bonding there as Mike holt suggests. ??
 
brother said:
I always felt that the water pipe bond should be no more than a #10, and rods should have the bigger wire for the GEC. its not much but it would help.
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Why install a bigger wire to the ground rod? If we are lucky enough to achieve the magical 25-ohm resistance (suggested in the FPN) on the ground rod , and we have a 120-volt fault to the GEC, we will see 4.8 amps on the GEC. Last I checked 4.8 amps will not stress a #6 copper conductor at all....
 
haskindm said:
Why install a bigger wire to the ground rod? If we are lucky enough to achieve the magical 25-ohm resistance (suggested in the FPN) on the ground rod , and we have a 120-volt fault to the GEC, we will see 4.8 amps on the GEC. Last I checked 4.8 amps will not stress a #6 copper conductor at all....
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The point im trying to make is that maybe there will be more current flow on that bigger wire to the GEC rods than on the water pipe if a neutral is lost. At least this might limit some of the shock. I understand about the 25 ohms and 120v etc..
 
The 4 wire idea is good, but idiot proofing anything is difficult. If for some reason the 4th wire gets cut or a bad connection, the problem would surface again, due to the grounding electrodes at the house and a fault to ground happening. Due to the high resistance of the grounding electrode field, you could still have potential on the water line without tripping the overcurrent protection. GFEP on a residental service size scale would help, but not eliminate that problem, as the setting would have to be high enough (5 to 30 amps) to prevent nusiance tripping, but be functional. Also the metering would have to be moved to the street, as the POCO would not want the extra expense of a 4 wire system, plus redesign of meters to insulate the neutral. Some small utilites in Ohio already require this if you want an underground service.(metering at the pole)
 
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