pool shock

[mbm1953]

Re: pool shock

Being in the home remodeling business I have learned to take many photos during the building stages. To answer your question Rickcham, yes in fact I do have many pic's. With my limited knowledge for the the??need/requirement and importance of the bonding I didn't take photo's specifically of the bonding although I do have pic's of all the rebar/steel frame. I think I may have to and will take out a magnifying glass and see if I can locate any bonding ties. Thanks! Does anyone know of an expert in this type of problem in the NE Florida area? I found one in Windemere Fl at $250.00 hr starting from the time he leaves his door, almost three hours away! I realize it will cost me up front to get the problem fixed and then hopefully I can get the pool company to reimburse my losses through legal procedures.

 

[hurk27]

Re: pool shock

mbm1953 quoted: and the only sure way of eliminating the source is to disconnect the grounding wire coming from the main panel.

If this does remove the voltage on the pool then it seems to be coming from the grounding of the house. this path could lead you to the FPL pole but it must be checked at each stage removing the meter will not break the neutral bond across it as the neutral it self has to be removed.when FPL disconnected the power from the transformer did they disconnect the neutral to it also? if they didn't then the voltage would still be connected. have FPL turn off the power to the meter then lift the neutral if the voltage is gone then it has to be coming from the power grid. what it sounds like to me is an elavated MGN on the pole causing your grounding to be elavated a few volts and if it is the only thing holding it down to a few volts is the grounding electrodes. have your electrican look for neutral current after the main has been turned off this is a good indcator of stray current the next step would be to lift the neutral but this is dangerous with out the power turned off to the meter. But it can be done.

 

[Ed MacLaren]

Re: pool shock

the only sure way of eliminating the source is to disconnect the grounding wire coming from the main panel.

There is the answer to this problem, and hurk27 came up with it way back on August 27, when he said-

Is this pool being fed from a sub panel?
If it is there a bond between the neutral's and grounding conductor? any time a bond is made between the neutral and a grounding conductor there is the potential for the voltage drop of the neutral to be placed upon the grounding. This voltage drop will place a differential voltage between the grounding and earth.

I'll bet when the POCO "removed power from the transformer providing service to my house" all they did was pull the primary fuse, and left the neutral connected.

Suggest you do what hurk27 suggested in his last post above.

Ed

 

[mbm1953]

Re: pool shock

OK, I mentioned I had limited knowledge of electricity but it is definitely growing quickly.
Hurk27 I will definitely have FPL out here again on next Tuesday and try what you suggested in your last post...thanks. I do have a question though "What is an elevated MGM on the pole"
I appreciate all the responses, comments and suggestions you all have provided so far and I will be sure to keep you updated after each troubleshooting stage.

 

[gwz2]

Re: pool shock

Just questioning.

Is the transformer configuration, 3? 4W Delta, not the System Source and the High Leg must be considered even if not part of the individual panelboards?

I certainly agree that the 3W panelboard with the Neutral is treated as a 1? panelboard, but does it meet the system definition ?

I would like to see an a acceptable, precise Neutral definition also.

gwz2

Editing - ThoughtI was on the NEUTRAL post.

Don't know how I got to this subject when posting.

[ October 22, 2003, 07:43 AM: Message edited by: gwz2 ]

 

[hurk27]

Re: pool shock

mbm1953
Elevated MGN is when the MGN has a voltage potential between it and the earth on which we stand which is why when we are on earth and touch somthing that has an elevated voltage we feel a shock.

A elevated MGN (main grounding neutral) It is the return wire on the pole that is common between all the transformers It would be the primary neutral conductor, But is also connected to the secondary neutral by a jumper on the transformer this allows for any voltage above earth potential to transfer to the service of a house. One thing that can happen is when your transformer is on a non-loop run (like a dead end street) and this MGN looses connection at the tap at the beginning of the run all the transformers on that run are now pulling power through the grounding electrodes and not through the intended path. if the resistance of the electrodes are high enough the voltage on this MGN will be elevated above earth and if you were to put a voltage meter between them, you would see a voltage. How much would depend on how high the resistance of the electrodes are. This is just one of the ways the MGN would be elevated the other is when the MGN has been hit by lightning or damage from a tree hitting it some of the strands of the cable might have been compromised and can no longer carry the rated load this will cause a voltage drop across the damage point and cause the voltage to rise on the down stream side of this point. the third way that I can think of is if the power company has allowed to many new houses hooked up and have over loaded the line to the point that there is now a voltage drop on the line this can also show up on the houses service grounding. this is one of the reasons why we have to separate the neutrals and grounding after the service disconnect as it can be caused by a neutral to ground bond at a sub panel and then the voltage drop in the neutral will show up on the grounding that is connected to that sub panel. by running a separate grounding wire that will have no current being drawn from it there will be no voltage drop and the grounding will stay at the main service potential. (0 volts to earth)

Hope this helps you to ask the right questions when the FPL gets there.

[ October 22, 2003, 07:41 PM: Message edited by: hurk27 ]

 

[gwz2]

Re: pool shock

It is my understanding that the MV cables of 4160V and higher have two standards for the sizing of the grounded ( sometimes Sheild ) conductors.

Some may have a 1/3rd size per 1/C HV cable and when on a 3? system of using A, B, C, and 3 of the 1/3rd grounded conductor ( may be a shield ) size makes a full size grounded return conductor.

Now if one of these cables with a 1/3rd size grounded conductor is used for a 1? HV to feed transformers down a street ( or alley), the ground return path is 1/3rd the size of the ungrounded conductor and the earth or other nearby electrical paths such as metal water mains are ' in parallel ' with the 1/3rd size grounded conductor return path, oops a voltage drop along that path.

May be part of the pool problem.

gwz2

[ October 22, 2003, 08:37 PM: Message edited by: gwz2 ]

 

[mbm1953]

Re: pool shock

I'm reading your inputs everyday and appreciate them. FPL and an electrician should be here on Tuesday so all the information I have when they get here will definitely help.! Thanks Again!

 

[bennie]

Re: pool shock

Inject this 1.5 volts into a spectrum analyzer and determine what kind of electricity is present.

There is too many of these "tingle voltage" complaints. I think this is a natural phenomenon and can only be corrected by wearing a bonding chain on the body to the grounded metal. Makes swimming difficult

 

[brian john]

Re: pool shock

MBM:

Not sure where your at in FLA but try to locate a company that has someone experienced in grounding issues. You will need to contact several contractors, testing firms and look for the someone they all name. Some of the firms will state they will give it a shot, unless they have a GOOD trouble shooting back ground, perseverance and a background in ground issues they either will give up, run up the T&M bill. There is a reason shock problem exist and so far the trouble investigators are missing the boat.

 

[brian john]

Re: pool shock

1.With all appliances on set up a meter to measure the voltage.

2. Is there any place where you can measure current on the ground system.

3. Turn off appliances/circuits one at a time checking your test equipment for changes in voltage and/or current.

4. Megger all neutral conductors, the neutral must be isolated and all loads disconnected.

5.Ccheck for grounded neutrals downstream from the service.

6. Identify the voltage wave form with a scope.

7. Verify NEC proper grounding and bonding.

8. Is the grounding electrode system installed by the contractor bonded to the house service grounding electrode.

 

[brian john]

Re: pool shock

Sorry: If none of the above work go to the next step and there is a next step, just not sure what it is at this time. Please keep us informed.

 

[bennie]

Re: pool shock

I think this is a natural created phenomenon, of chemical reaction, producing a difference in the electrical charge between the two pools.

The only known correction is to ground the two pools. What I mean by ground, is to fill them with dirt Otherwise don't put body parts between the two pools.

 

[brian john]

Re: pool shock

Bennie: As an owner of a swimming pool, I can't agree more, the best way to save money is to "GROUND" them. A friend of mine digs swimming pools and he told me I'd be surprised by the number of parents with grown kids that have their pools filled with DIRT.

 

[Guest]

Re: pool shock

My friends make them into ponds. But, maybe that's why everything dies except the eels