Poor grounding electrode???

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sparkease

sparkease

mjet said:
Hi, I have a 120/240 200 amp underground service at my vacation home. The problem is there is stray voltage 30 volts on cold water sill cock outside the house. When using water and ground is wet in bare feet you get shock from fauct,not safe.The service is properly bonded and grounded.The area is all sand where the ground rod is driven and very dry. Connections clean and tight. Could this area need more ground rods to make a grounding mat because of poor soil conditions.It is a well with pvc casing so the only grounding electrode is driven copper rod 8 foot. I appears that the wet soil under the spicket is a better ground than driven rod when water is used.Could edison have a poor bond on pole transformer ??
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did you jumper the hot water heater? if not only one side of water system is bonded due to isolation bushings in connections.
 
Sparkease

Sparkease

did you jump water heater?if not only cold or hot is bonded.to test run a temp. wire from sillcock to ground rod if voltage is gone then rod is not problem.
 
Hey all.....
Was on my mind so had to post.

Making funny and light of cooking..smell..etc...

All be safe out there.

Was showing my 4 yr old grandson electricity (via a wiggy) showing him invisible and how it can kill or hurt you (playing around a lamp chord being pulled out...sticking things in a receptacle...and tell his friends).

Pulled up some pics of burns.

Long story short..............serious stuff.

Be safe out there.

(as a note, I was most concerned during the learning process (things fail...... including testers) but his eyes lit up when we did 240v in the panel.............what a kid!!!!)
 
K8MHZ said:
It was probably like my first experience with 277v lighting in a dropped ceiling on a hot, humid day with my sweaty neck touching the metal frame.
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On the load side................................



That'll wake you up..........:D
 
ritelec said:
Touche'...............

Reminds me of my first experience with a high leg.
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There where alot of opened spaces in a panel.....................great, I'm in.

Hooked a whole bunch of incandescent bulbs on a circuit fed from one of these spaces........MAN were they bright when I turned them on..:D

Till one by one they burn't out.

(note......I said to myself never do that again, but I few years later, I hooked up a 120v circuit on a high leg buss ON A SERVICE THAT I PUT IN!!! and burnt someones radio..........it happens and I suk).
 
Hi guys, yes still following hear just taking as much as i can and see whats making sense here. Some post say if the main is off its not utility not to sure on that that just stops all current flow.When main is off there is no unbalance current to flow. There has to be a reason for current to flow through sill cock to wet soiled ground.If there was a high resistance short somewhere would that make sense.But still should travel to grounding electrode system.
 
mjet said:
Hi guys, yes still following hear just taking as much as i can and see whats making sense here. Some post say if the main is off its not utility not to sure on that that just stops all current flow.When main is off there is no unbalance current to flow. There has to be a reason for current to flow through sill cock to wet soiled ground.If there was a high resistance short somewhere would that make sense.But still should travel to grounding electrode system.
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It is a high resistance and it is in the neutral conductor. You need to determine where it is. It can be on either side of the meter and can include the connection to POCO transformer. Turning off the main makes problem go away because neutral is no longer loaded. If turning off the main did not make problem go away then you would know the source of this stray voltage is coming from off site. The chance of it being a fault of an ungrounded conductor to the water pipe is pretty slim. If the water pipe is bonded to the neutral that should cause large current and operation of overcurrent device. If pipe is not bonded then you will likely have near or full 120 volts to earth.
 
mjet said:
Hi guys, yes still following hear just taking as much as i can and see whats making sense here. Some post say if the main is off its not utility not to sure on that that just stops all current flow.When main is off there is no unbalance current to flow.
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When the main is off it will help determine (troubleshoot) where the problem is. Maybe stop reading into it......if the...and then the......Shut the main off and go from there.

PUT YOUR SHOES ON.
 
Thanks guys for all the help i will be up the in a few week to resolve the issue.One of the senior member contacted me about this situation and really made alot of sense. Thanks for all the information and will post when we solve the issue.

Thanks again

MJET
 
120309-1811 EST

mjet:

I have not really analyzed the comments so far, but I have skimmed over them.

Ferndale is an old city. City water is probably cast iron pipes. From the street to the house is possibly galvanized. If this has not been modified by addition of plastic pipe in the path somewhere, then it is a fairly good connection to earth. Your house is likely to have been built in the 1920s.

It is also possible your primary electrical distribution is delta.

First, try to find your transformer. Are there three primary wires at the top of the pole? Are there two primary bushings on the transformer? See my photos at http://beta-a2.com/misc_TMP_photos.html . In particular P4. Mine is a delta source with no primary ground. It may be a Y at the substation, but it is delta as far as I am concerned.

If your transformer is not too far away and your neighbors don't mind, then get a long insulated wire. Possibly #16. Run this wire from the area of your house and yard to the transformer pole.

Because we do not know what to expect use insulated gloves and boots. At the pole and very close to the pole ground rod push a long screwdriver into the ground. Connect your wire to this probe. Back in your yard use another screwdriver as a probe. Use a high impedance meter, such as a Fluke 27, to measure the voltage between the yard probe and the wire to the pole. In my yard this does not go above about 1/4 volt.

Probe various points in your yard with your main breaker off, or main fuses pulled, or main disconnect switch open. If this voltage is more than a volt. Note its value in extreme positions in your yard, and report back. Also turn power back on in your house, but only one phase, and provide a substantial load like a 1500 watt heater. Now what are the yard voltages.

Next with your main disconnect open, whatever it is, measure the voltage to your water meter, to your gas line, to a main sewer pipe, and to your main panel neutral bus.

I will be back with more tests later.

.
 
120309-2211 EST

Continuing with my comments.

It is important to determine if your primary supply is delta or Y.

I do not believe a delta will have a ground wire run from pole to pole and thus there is negligible current that should flow in the ground form one transformer area to another. A current from one transformer area to another would only flow in the earth under some type of fault condition.

With a Y primary the primary neutral runs from pole to pole over the entire path from the substation to the end transformer. This neutral is also shared with the neutral on the secondary of every transformer. At at each transformer there is a ground rod at the pole connected to the common neutral system. With open neutrals along this power company distribution line there can be substantial currents thru the earth. At the moment I am not talking about open neutrals from the transformer to your house. These ground currents can set up noticeable undesired voltages between different locations.

Going back and looking at your original post I see I am somewhat off base. Your location of interest is not Ferndale. So it is probably upstate and likely very sandy. Treat my comments on pole transformer as meaning the pad transformer. There will still be a ground rod or equivalent there. Maybe not closely accessible. Then just use a probe close to and/or touching the transformer base, or may be connect to the transformer enclosure. This assumes a pad mount vs pole.

Almost certainly out in the woods you are fed from a two wire primary with one wire grounded (earthed).

My probing comments still apply.


Assume that you can get a reasonably good connection to the ground connection at the transformer. Now you have a useful reference point that hopefully is essentially the center tap output terminal of the transformer.

Close the main breaker, and load up one phase (one supply leg), and totally unload the other phase.

All the following measurements are relative to the ground reference point at the transformer.

Measure the voltage on the grounding electrode. With a probe measure the earth voltage about 1 ft from the grounding electrode. I would expect under 1 volt.

Measure the voltage to your hose faucet. Measure the voltage to the earth near the hose faucet.

What kind of water pipes do you have? If you assume copper, then the voltage at the hose faucet should be no different than that at the grounding electrode.

There are all sorts of possible problems. This information should provide some guidance on where to go next.

Keep in mind there should be little difference in voltage anywhere in the metalic conductive portion of of the neutral and ground system while under heavy unbalance load.

.
 
Just curious why you care whether the primary is wye or delta (three or four wire). If there is no neutral on the primary side, there is still a grounded neutral on the secondary side of the transformer. A two bushing transformer only means that the transformer has no internal bonding on the primary side. Is some states (such as California) the case of the transformer is not allowed to be grounded, so the primary must have two bushings, even if one of them is connected to the primary neutral of a four wire system. Some states also do not allow the use of the primary neutral as a common neutral for the secondary. In either case, there would be a pole ground and a ground connection to the transformer secondary neutral bushing. The fact that the unwanted voltage goes away when the main is truned off eliminates the possibility of stray voltage from the primary distribution system or some other offsite source.
 
120312-1245 EST

The reason, a three wire delta as the primary source is important, is because there is no primary neutral link from one transformer to the next and shared with the secondary neutral. Thus, a bad primary neutral, because it does not exist, can not cause ground currents of any substantial amount in the secondary neutral circuits.

With this isolation you are only concerned with neutral problems related to the local area of whatever exists on the secondary of the transformer.

Independent of this there can be some ground currents from other sources, but these cause little voltage drop over a reasonable distance. My measured few tenths of a volt or less over a 12 ft distance.

.

.
 
meternerd said:
Just curious why you care whether the primary is wye or delta (three or four wire). If there is no neutral on the primary side, there is still a grounded neutral on the secondary side of the transformer. A two bushing transformer only means that the transformer has no internal bonding on the primary side. Is some states (such as California) the case of the transformer is not allowed to be grounded, so the primary must have two bushings, even if one of them is connected to the primary neutral of a four wire system. Some states also do not allow the use of the primary neutral as a common neutral for the secondary. In either case, there would be a pole ground and a ground connection to the transformer secondary neutral bushing. The fact that the unwanted voltage goes away when the main is truned off eliminates the possibility of stray voltage from the primary distribution system or some other offsite source.
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Why would you not want the transformer case grounded, or require it to not be grounded? You would want a low impedance path for fault current should the case become energized so that overcurrent protection will operate faster.
You would definately want this for a pad mount transformer where case is readily accessible to people.

As far as primary neurtal and secondary neutral not allowed to be common --- if they are both grounded they are the same potential you want them bonded together so they remain same potential. The only way to eliminate voltage drop on primary neutral is to not use it as a current carrying conductor, otherwise it is managed by balancing the load and keeping the neutral current as low as possible.
 
On pole mounted transformers, the state of California considers any ground within reach of a lineman a signifigant hazard. Cases of tranformers, guy wires, etc. are required to be isolated from ground to reduce the possibility of incidental contact. All transformers used in California (as far as I know) are two bushing transformers. Some utilities allow "common neutrals" where the primary and secondary neutrals are tied together and grounded and some do not. This applies to overhead only.

When a separate neutral is used, the primary neutral is considered a phase.

Getting a little off the original post, but a good topic anyway.
 
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