Bonding/Grounding copper water lines

rcmoon

Member
Location
Florida
This is a true story...

The service drop bare neutral conductor got energized from the service drop hot conductor because the insulation on the hot conductor deteriorated. This caused all the neutral and ground conductors in the home to become energized. We know that the norm for grounding a service at a home is to run a ground wire to a ground rod and then to the water pipe. In the case above, I would assume that all the water pipes in the home would have been energized as well as all the neutrals and ground wires since the service drop neutral is tied to the ground wire in the meter can. Fortunately no one was washing their hands or taking a shower at the time this happened.

My questions are...
Would someone have been electrocuted if they were washing their hands or taking a shower?
Would it be safer to not tie the ground wire from the service to the water pipe and run a separate ground rod just for the water pipe?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
This is a true story...

The service drop bare neutral conductor got energized from the service drop hot conductor because the insulation on the hot conductor deteriorated. This caused all the neutral and ground conductors in the home to become energized.

How is this possible?
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
A hot to neutral connection would be a fault and blow the fuse on the poco transformer.
Unless a compromised neutral blew first. One fault leading to the other.

To the OP: An energized neutral in combination with a high water pipe to soil resistance could create a dangerous shock hazard between bonded metal or water and a true earth ground like metal drain piping.
Adding another ground rod would be next to useless and not bonding neutral to water pipe would be an NEC violation.
Adding a bond to the drain piping too, although not required by code, would address this particular problem.
 

rcmoon

Member
Location
Florida
Unless theres another reason (other than the NEC says) regarding tying the ground/neutral wire to ground rods then to my water line, it seems to me based on the issue I had, it would be best to not have my water line tied to the ground wire from the service. Then if the same thing occurred it would NOT send voltage onto my water pipe. I don't think I would need to install a ground rod just for the water pipe since its already under the slab in the ground, so a ground rod would serve no purpose.
 
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user 100

Senior Member
Location
texas
Unless theres another reason (other than the NEC says) regarding tying the ground/neutral wire to ground rods then to my water line, it seems to me based on the issue I had, it would be best to not have my water line tied to the ground wire from the service. Then is the same thing occurred it would send voltage onto my water pipe. I don't think I would need to install a ground rod just for the water pipe since its already under the slab in the ground, so a ground rod would serve no purpose.

It's a very bad idea to leave your water metal pipes unbonded, trust us.:) If they ever get accidentally energized for some reason, they will stay that way as there will no decent path back to the source and the breaker controlling the ckt allowing the fault won't open and some freak ocurrence with the utility will be the least of your problems- who ever comes into contact w/ that plumbing will end up completing a circuit. This still sounds to me though like you lost a svc neutral- a line to neutral ( if big enough) fault would blow the fuse at the tranny as mentioned by ActionDave, though Goldigger has a good point.

Could have just been coincidence- insulation was bad on one of service legs, neutral just went bad as a separate issue- what did the poco say?

Do you have metal gas pipe in your home? Guess what- it's likely bonded too in some form or another- food for thought.:)
 
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rcmoon

Member
Location
Florida
It's a very bad idea to leave your water metal pipes unbonded, trust us.:) If they ever get accidentally energized for some reason, they will stay that way as there will no decent path back to the source and the breaker controlling the ckt allowing the fault won't open and some freak ocurrence with the utility will be the least of your problems- still sounds to me though like you lost a svc neutral- a line to neutral ( if big enough) fault would blow the fuse at the tranny as mentioned by ActionDave, though Goldigger has a good point.

Do you have metal gas pipe in your home? Guess what- it's likely bonded too in some form or another- food for thought.:)

Don't have any gas pipes. It seems theres a better chance of my water pipes getting energized from what happened in my case than some other way. I would think this has happened many times. Tree branches can rub a bare spot on the service hot wire causing it to come in contact with the bare neutral wire. As you know its common for service drops to run between trees and branches. By the way, I didn't lose a neutral. My neutral got energized. It damaged a lot of stuff in my house, luckily the utility co reimbursed me for the damage.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
This is a true story...

The service drop bare neutral conductor got energized from the service drop hot conductor because the insulation on the hot conductor deteriorated. This caused all the neutral and ground conductors in the home to become energized. We know that the norm for grounding a service at a home is to run a ground wire to a ground rod and then to the water pipe. In the case above, I would assume that all the water pipes in the home would have been energized as well as all the neutrals and ground wires since the service drop neutral is tied to the ground wire in the meter can. Fortunately no one was washing their hands or taking a shower at the time this happened.
I don't understand how that can happen unless the neutral to the utility transformer was open. If the neutral is in good condition, the voltage on everything connected to the electrical grounding system would be limited to the voltage drop on the neutral between the fault and the transformer.

My questions are...
Would someone have been electrocuted if they were washing their hands or taking a shower?
There would be a shock hazard if the person is touching the water and something that is grounded and not connected to the electrical grounding system.
Would it be safer to not tie the ground wire from the service to the water pipe and run a separate ground rod just for the water pipe?
Would not be safer...if the same thing happened and some one was touching the water and anything connected to the electrical grounding system, you would have the same shock hazard. Also a issue if the there would be a fault to the water pipe...then the pipe is energized and there will be a shock hazard between the pipe or the water, and anything that is connected to the electrical grounding system.
 

rcmoon

Member
Location
Florida
Unless theres another reason (other than the NEC says) regarding tying the ground/neutral wire to ground rods then to my water line, it seems to me based on the issue I had, it would be best to not have my water line tied to the ground wire from the service. Then if the same thing occurred it would NOT send voltage onto my water pipe. I don't think I would need to install a ground rod just for the water pipe since its already under the slab in the ground, so a ground rod would serve no purpose.


Supposed to say " Then if the same thing occurred it would NOT send voltage onto my water pipe."
 

rcmoon

Member
Location
Florida
It seems theres a better chance of my water pipes getting energized from what happened in my case than some other way. I would think this has happened many times. Tree branches can rub a bare spot on the service hot wire causing it to come in contact with the bare neutral wire. As you know its common for service drops to run between trees and branches. By the way, I didn't lose a neutral. My neutral got energized. It damaged a lot of stuff in my house, luckily the utility co reimbursed me for the damage.
 

rcmoon

Member
Location
Florida
I appreciate all the opinions. However after what happened in my case, I'm still not convinced that the water lines should be tied to the neutral/ground wire system at the service. I would think this has happened many times and most EC's wouldn't know about most cases since it would be a utility problem not an EC problem to correct. It would be nice if Mike Holt chimed in on this one.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
Licensed Electrician
I appreciate all the opinions. However after what happened in my case, I'm still not convinced that the water lines should be tied to the neutral/ground wire system at the service.
They absolutely should.

I would think this has happened many times and most EC's wouldn't know about most cases since it would be a utility problem not an EC problem to correct.
You have not fully described at all what happened. I'm glad you are okay, and I'm glad the poco fessed up and paid up (that doesn't always happen). The details of your ordeal are lacking.

It would be nice if Mike Holt chimed in on this one.
He is unlikely to.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
To me the OP's concerns remind me of those who argued against seat belts out of fear of being trapped in a burning car.
When you balance an unlikely or nonexistent disadvantage against much more likely advantages the anecdotal argument cannot stand up.
 
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