Voltage Between Neutral and Ground 38 Volts

Might be ghost voltage = no amperage....best way to determine is to put a load on it, if it disappears it's probably just induced voltage...this would be from close proximity of the neutral wire to current carrying lines....

Thank you for the reply.

I noticed it before on a steel construction too. Got lightly shocked when my bare arms were sweaty. Will try it tomorrow. D.

Ceiling fans down here are notorious for partially shorted shaded pole motors, shock you when you touch the chain barefooted...you can't tell because they still run...

GA, un-grounded neutrals can cause all kinds of mischief. I recall as a child occasionally getting a tingle at the hose bib (faucet) and I told my dad about it. He investigated that and noticed that the neutral at the pole pig (transformer) had broken loose. One call to the electric company and they were there inside the hour to fix it.

A voltage between neutral and ground/earth merely indicates that there is a current flowing in one of them, usually the neutral.

A review of the installation test records will indicate the earth loop impedance. Multiply by the current in the neutral conductor and, hey presto, <...38 volts...>.

Fundamentally what you posted is correct. It is not my field but 38V seems like a huge amount of E=IR loss within the on-site wiring.

Stated another way, IF you start off with the assumption that the lines are driven by 120V then 38V lost in neutral wiring would imply 38V also lost in hot wiring (other side of the loop). So, 120V - (2 * 38V) = 44V on load. That is a HUGE amount of loss and possibly some warm wires.

Once again I'll add the "I'm not an expert" fine print but my vote remains to contact someone of authority quickly. A "resort and marina" tends to have a lot of wet people walking around with bare feet. This is not an ideal location to have wiring problems.

"To get a more universal 240/120 split phase on each of the phases (3 transformers = 9 hubs with 240/120 V/ 60 Hz."

I don't understand this. Can you provide a drawing?

"Today I measured 210 volts in the marina and 38 volts between the ground and neutral"

Was this measurement on a 208V line or a 240 volt line? Was it measured under normal load?

"The ground is established by blank copper wires 2 OT in the seabed - 4 pieces."

Are you saying there are ground rods driven into the ocean floor? If so, how many and how deep? The ground and neutral should be tied together somewhere, so resistance between the 2 could be the problem.

We have 3 transformers 11kV to 208/ 3 phase 500 kVA. In most buildings 2 phases are used and they are connected as 104/N/104 volts. Except that the power company puts more output and the phase voltage climbs to 255 Volts - to the neutral about half.

The marina is a sea marina and the grounds are all submerged with 8 feet salty sea water and about 3 ft in the bed. All blank copper (full of algae)

The marina has about 3/4 of a mile canal wall with the docks perpendicular to it.

They get fed by the closest transformer which is by all 3. Same for the buildings that follow the waterline.

Interesting, but you didn't answer any of my questions. Do the ground wires run all the way back to the power pole? How are they bonded?

Something is very fishy here! A lot more information is needed!

A three-phase transformer does NOT provide split-phase voltages. A normal 208V Wye 3-Ø transformer does NOT provide 104/N/104; it provides 120/N/120, but those two 120V lines are 120° out of phase, not the 180° required for split phase 240/120V.

255V is almost 123% of 208V. If this were due to excessive incoming power, that 11kV would have to rise to 13.5kV. Assuming you are located in the USA, the incoming voltage that high would be reason to sue the power company, but I seriously doubt that your problem originates with the power company. I agree with the others: you have a wiring problem, almost certainly involving the ground.

There should be a ground rod driven into the ground within a few inches of each transformer, and of course connected to the transformer output ground. Is there? This commonly requires drilling a hole through the concrete where the transformer is mounted.

IMO we have a wye (star) connection on all the transformers.

We have indeed no real split phase, since no other transformers are applied.

a star 208 V is supposed to give 208/1.73 = 120 volts. I have it under test now where everything is recorded.

Will pick up the thread next week. Some yachts have real split phase 120 N 120 in phase and they have an alarm when we give them the 120 degrees phase shift from our system.

They feed us 13.5 kV on regular basis.

I agree with the first three paragraphs.

"Some yachts have real split phase 120 N 120 in phase and they have an alarm when we give them the 120 degrees phase shift from our system." That's as it should be, since any 240V devices will be receiving 208V, which is 15% below nominal, well below the 10% variance commonly specified. Any heavily loaded 240V motor, such as an air compressor motor, may not start, and if some form of under-voltage protection did not disconnect it, it would likely burn out that motor.

Again, I have to ask where are you located? If you are located in mainland USA, I don't believe that kind of variance should be tolerated. In any case, you should have some form of over- and under-voltage protection. Ideally, this protection would disconnect the source from your transformers, to protect them and your lower voltage devices.

Maybe this won't be <...Off Topic...>.

Quite often there is a voltage between N & E, and explained by all sorts of reasons.

A lot depends on where the N is connected to E, the impedance, current flowing, and where you measured the voltage, because if at the point of use, just touching the N could be lethal.

But why has #5 been marked OT ? I appreciate a study of harmonics and zero-sequence fault analysis might a bit too much for you - but certainly not OT.

But more to the point, the OT suggests expert knowledge by the poster who gave it, that for very good safety reason, instead should be spent giving advice what to do about your installation to avoid electrocution - if for some reason you (or any person) could touch the neutral with bare hands.

You are dealing with a very dangerous subject,with potential deadly consequences.

I could advise,but I do not want any part of contributing to the consequences of misinterpretation.

There are too many variables to address here,such as the difference between bonding and grounding,the difference between grounded and grounding conductor,etc.

Please hire a qualified licensed electrician to find your problem before someone is seriously hurt or killed.

In most states,it is illegal for any unlicensed person to work on anything except plug-and-cord connected items.

If there is <...38 volts between the ground and neutral...> then there is a substantial current in the <...neutral...>. Under those circumstances it would not be surprising if the incoming supply voltage had dropped to <...210 volts...>, and it would also not be surprising that whatever is protecting the <...400 amps feed...> were close to its operating point!

For the voltages you measure it is most probable that the neutral you are measuring has become disconnected from or has a high resistance to the neutral connection at the transformer supplying the circuits measured.

The neutral voltage on the conductor you are measuring is being slewed towards one of the phases by an unbalanced load.

Get it checked for the neutral fault. I have seen this happen when one of the phases brakes and fails to earth. This can get worse and may prove fatal to someone contacting a tap or something connected to earth.

Check the phase to earth voltages as well as neutral to earth assuming your state uses MEN, multiple earth neutral. The neutral to earth should never be more than a few volts and is usually millivolts.

Only the main panel should have the neutral(Grounded) and Grounding(green) equipment conductors bonded together.

All sub-fed panels should have the equipment ground(green or bare) and neutrals separated.Any bare grounding condcutors should be taped to prevent contact with the neutral.

This prevents the unbalanced neutral current from having more than one path,which seems to be the problem with your installation.

Make certain that all equipment grounds and neutrals are separated in any sub-fed panels and that bonding and grounding meets the code requirements.

One of the things that needs to be established is the integrity of the neutral conductor all the way back to the local distribution transformer. A dirty connection in the neutral on the way from the transformer could easily suggest <...38 volts between the ground and neutral...>, which is merely an indication that there is imbalance in the three phase currents coming off the transformer, which imbalance is perfectly normal for three sets of single phase loads.

Get the installation checked out by a qualified local Electrician at the earliest opportunity, and ideally before someone gets hurt.

Why the Neutral and Equipment Ground should only be bonded at the main panel.

https://duckduckgo.com/?q=why+to+bond+neutral+and+ground+only+at+the+main+panel+video&t=newext&atb=v352-1&iax=videos&ia=videos&iai=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D5iEuaAYs5x4

Sounds like maybe the bonding jumper may not have been removed in the sub panel(s).

Check all of the sub panels to see if the bonding lug is still connected.

If the neutral is broken at the main panel,all loads become connected in series,and the voltage at each device will vary depending on which other devices are connected.Current is constant in a series circuit.

I have seen this happen and many devices are destroyed by over/under voltage.

Here is a link to help you understand the NEC requirements for marinas,boat docks,etc.

https://www.ecmweb.com/search?filters={%22text%22:%22requirements%20for%20marinas%22,%22type%22:[],%22websiteSchedule%22:[]}

Read,understand and learn why only qualified electricians should perform work in theses locations,in particular.