Ideas needed,,,

Status
Not open for further replies.
E

Electrick One

Member
Location
North Carolina
I got a report from one of my crews, concerning a call their on. The customer has an inground swimming pool and there is noticable voltage on the metal ladders and stair handrails. It's not a lot of voltage, but if you hold the metal parts and touch the water, it can be felt. I had the guys disconnect all power to the pool equipment, condition still exists. Had them disconnect service Main, condition still exists. Last hope,Hail Mary, I had them pull the meter from the base, condition still exists. Any suggestions?
 
They say they're can feel an electric shock when they touch the metal parts and the water at the same time. But all the power has been disconnected from the service. I'm scratching my head on this one.
 
stray from where,,, they pulled the meter
Click to expand...
Often from the utility primary grounded conductor.
Does this pool installation have the bonding required by Article 680? Is there a pool pump? Is the pool bonding connected to the pool pump EGC?
Don
 
I thought of the ungrounded conductor. Since my last post, I had them disconnect the ungrounded service conductor from the meter base, and the condition still exists. So we now have no connection to the utility service whatsoever, but the condition still exists. Any thoughts?
 
Often from the utility primary grounded conductor.
Does this pool installation have the bonding required by Article 680? Is there a pool pump? Is the pool bonding connected to the pool pump EGC?
Don[/quote]

We wired this pool around six years ago, all bonding is correct.
 
Disconnect any connection to the building electrical system to see if it goes away. If the pool and building piping is metallic, disconnect that too.
So we now have no connection to the utility service whatsoever, but the condition still exists. Any thoughts?
Click to expand...
You still have a path via the grounding electrode system. I think this is from the utility primary. Is the utility primary distribution overhead or underground?
don
 
The service is fed from overhead. Service riser is PVC with 2/0 copper conductors. My electrician disconnected the ungrounded conductor from the meter base on the line side ,and they disconnected the base from the driven grounding electrode. And the condition STILL exists. I told them to ask if the house was built on an Indian burial ground. :lol:
 
The pool is not bonded to the system EGC.To test this take one end of a long conductor and using a gator clip attach one end to the grounding electrode conductor. Bring the other end to the pool and connect it to one of your voltmeter leads. Drop the other lead onto the water. You will probably read about 10 volts. If so connect the conductor to the ladder. Measure the voltage form the water to the ladder. It should be zero. If so
the pool is not bonded properly.
 
The pool equipotential bonding doesn't need to connect to the premise wiring EGC to work properly, quite the opposite actually.

Don is on target. This is going to be a utility thing or a neighbor problem. See if you can get any of your neighbors to disconnect their services to see if the stray voltage goes away. I am willing to bet you are going to have a hard time convincing the POCO it is their problem.
 
jwelectric said:
Another case to support the bonding of the pool water to the bonding grid.

I think that this was a proposal to either the 99 or 02 cycle.
Click to expand...

Another case to get POCO to redesign their systems.

(Don't want to go there--check our hosts website for any info on "stray voltage")
 
I understand your point Bryan, however, with the service being completely disconnected from the utility source of power, both grounded and ungrounded conductors, how is it still possible for the voltage condition to exist? The conditions at the pool have not changed, there's no voltage comming in, but we still have 23 volts at the pool . I'm stumped.
 
Bryan,
The pool equipotential bonding doesn't need to connect to the premise wiring EGC to work properly, quite the opposite actually.
Click to expand...
Unfortunately the code requires this connection. 680.26 requires that the bonding be connected to the electrical equipment and because the electrical equipment is required to have an EGC, the code requires that the pool bonding grid be connected to the electrical grounding system. In previous codes, you could eliminate this tie by using a double insulated pool pump, but that was changed in the 2002 code.
680.26(B)(4) ... Where a double-insulated water-pump motor is installed under the provisions of this rule, a solid 8 AWG copper conductor that is of sufficient length to make a bonding connection to a replacement motor shall be extended from the bonding grid to an accessible point in the motor vicinity. Where there is no connection between the swimming pool bonding grid and the equipment grounding system for the premises, this bonding conductor shall be connected to the equipment grounding conductor of the motor circuit.
Click to expand...
The code actually requires us to energize the pool grounding grid.
The problem voltage normally comes from the voltage drop on the primary neutral. The utility bonds the primary and secondary neutrals at the transformer. The problem is much worse if there is any type of poor connection on the primary neutral, but even without a problem there can be a few volts of drop on this conductor. This "dropped" voltage shows up as voltage to remote earth (earth outside of the influence of any grounding electrode). In the case of the pool, the code required bonding of the metal parts energizes these parts at that voltage.
Don
 
If there is an open neutral somewhere close by then this could be causing this problem.

How close are the houses together?

It is now time to call the power company.

This is the opinion of only one person but my opinion is the safest pool in the world is one that has been back filled.
 
We got the power company out to the site, they pulled the jacks on the transformer, and we still have 23 volts at the pool. :shock: :shock:
This is an older house, built in the late 50's, early 60's. We upgraded the service in 90, during a remodel and wired the pool six years ago. All the proper grounding and bonding has been done on the entire system, and is still in place. This house is located well away from any other houses,there is only one transformer, and they are the only customer on that transformer. (rural setting)

I've never seen anything like this. How do you still get voltage on the metal fixtures at the pool if there is NO connection to the electrical utility service?

:?
 
Does it have copper or some type of metal water pipe coming into the house? If so, with the water line coming in from the street and other houses also fed from the main from the street your could be picking up stray voltage from the other houses around you from the water. Maybe I'm not thinking right. If this could be the problem, unhook your water pipe from the house water meter going to the house. Then check to see if you have anything. Again it's been a long day for me so I'm shooting from the hip.
Jim
 
Status
Not open for further replies.
Top