Nuetral to Ground Voltage

[island Greg]

I would first like to say that I have browsed several older post on this subject here. But the subjects were much more involved then my simple question. Sorry in advance if my question has been discussed before. I just have not found anything to help answer / solve my problem.

I recently moved to a remote island off of Nicaragua. A restaurant asked me to install a 20amp receptacle. While doing this install I noticed that the neutral to ground (earth) gave me a reading of 56Vac. Hot to ground (earth) read 68Vac. This giving me 124Vac across hot to neutral. Everything seems to work fine in the restaurant, running fridges, freezers, fans, blenders and so-forth.

The ground (earth) is not connected to the neutral in any form. The ground is connected to the earth via a 8ft copper grounding rod.

Should neutral be connected to the ground? Or do I have another problem and this would create a short since the neutral's voltage is so high (56Vac).

Thank you for your time and response.

 

[GoldDigger]

I would first like to say that I have browsed several older post on this subject here. But the subjects were much more involved then my simple question. Sorry in advance if my question has been discussed before. I just have not found anything to help answer / solve my problem.

I recently moved to a remote island off of Nicaragua. A restaurant asked me to install a 20amp receptacle. While doing this install I noticed that the neutral to ground (earth) gave me a reading of 56Vac. Hot to ground (earth) read 68Vac. This giving me 124Vac across hot to neutral. Everything seems to work fine in the restaurant, running fridges, freezers, fans, blenders and so-forth.

The ground (earth) is not connected to the neutral in any form. The ground is connected to the earth via a 8ft copper grounding rod.

Should neutral be connected to the ground? Or do I have another problem and this would create a short since the neutral's voltage is so high (56Vac).

Thank you for your time and response.

They may be running and ungrounded 120 volt system, which is allowed and common in many countries other than the US. Europe is primarily ungrounded 220-240.
Arguments as to which is safer, based on both the theory and long experience are inconclusive, and it pretty much comes down to it being better to do everything in the country the same, either one way or the other.

There is nothing inherently unsafe about an ungrounded system, but it should have a ground connection detector in the circuit somewhere for maximum safety.
If the supply is from a generator, it indicates that the generator neutral is not connected to earth ground.
If the supply is from a utility it means that no point on the secondary of the service transformer is intended to be grounded, or that the ground connection is faulty.

The voltage you are reading is probably a phantom voltage caused by capacitive leakage from the hot and neutral connections in utilization equipment and the grounded case of the equipment.

Do not do anything to change it if it is normal practice in the area.

 

[Besoeker]

They may be running and ungrounded 120 volt system, which is allowed and common in many countries other than the US.

Possibly so though not genrrally my experience.

Europe is primarily ungrounded 220-240.

Not as a rule.
LV distribution systems here in UK, for example, are generally derived from a local distribution transformer that is 11kV delta primary and a 400/230V nominal star (wye] secondary. The neutral (star point) is earthed (grounded) at the transformer secondary. Residences are mostly served with the 230V line to neutral from such an arrangement. Ungrounded it is not.

Commercial and light industrial often takes all four wires. We do. Our works yard transformer is about 1500kVA. All the office kit runs on single phase 230V. Phone chargers and supplies for laptops and such can run on a range of voltages, typically 100 to 240.And 50/60 Hz. A bit handy if you travel a bit internationally.

Our test area has a number of three phase four wire outlets to test/demonstrate operation of the VSD systems and other stuff we make.
We also have a few test transformers to get voltages for non-standard kit.

 

[mbrooke]

Possibly so though not genrrally my experience.


Not as a rule.
LV distribution systems here in UK, for example, are generally derived from a local distribution transformer that is 11kV delta primary and a 400/230V nominal star (wye] secondary. The neutral (star point) is earthed (grounded) at the transformer secondary. Residences are mostly served with the 230V line to neutral from such an arrangement. Ungrounded it is not.

Commercial and light industrial often takes all four wires. We do. Our works yard transformer is about 1500kVA. All the office kit runs on single phase 230V. Phone chargers and supplies for laptops and such can run on a range of voltages, typically 100 to 240.And 50/60 Hz. A bit handy if you travel a bit internationally.

Our test area has a number of three phase four wire outlets to test/demonstrate operation of the VSD systems and other stuff we make.
We also have a few test transformers to get voltages for non-standard kit.

In Norway the norm is ungrounded 230volt for residential and commercial, 690volt ungrounded for heavy industrial ect. The wye XO at the transformer is often left floating but grounded through a surge arrester that will short to ground when there is a fault such as high voltage going into the low (ie, transformer winding crossing).

See page 14: http://www.elsif.no/fileadmin/Dokumenter/Hoyspenningsrapport.pdf

And the surge arrester for sale: http://www.el-tjeneste.no/files/Brosjyre-Nullpunktsikring.pdf

 

[kwired]

If it is an ungrounded system, you would think there would be some kind of ground fault indication otherwise what is the point of being ungrounded? You can have one fault on an ungrounded system and no operational problems, it just becomes a grounded system at that time via the faulted conductor, when there is a second fault is when operational problems will develop.

 

[mbrooke]

I would first like to say that I have browsed several older post on this subject here. But the subjects were much more involved then my simple question. Sorry in advance if my question has been discussed before. I just have not found anything to help answer / solve my problem.

I recently moved to a remote island off of Nicaragua. A restaurant asked me to install a 20amp receptacle. While doing this install I noticed that the neutral to ground (earth) gave me a reading of 56Vac. Hot to ground (earth) read 68Vac. This giving me 124Vac across hot to neutral. Everything seems to work fine in the restaurant, running fridges, freezers, fans, blenders and so-forth.

The ground (earth) is not connected to the neutral in any form. The ground is connected to the earth via a 8ft copper grounding rod.

Should neutral be connected to the ground? Or do I have another problem and this would create a short since the neutral's voltage is so high (56Vac).

Thank you for your time and response.

Do you have any pictures of the main panel? Utility service? Depending on the set up you could have numerous things going on.

The system may or may not be ungrounded. If the system is ungrounded its ok as long as you have an equipment ground wire from all appliances/outlets going back to the panel landed on a ground bar. However you may need a ground fault detector to indicate a ground fault.

Another possibility is your service could be 60/120 volts, 60 volts between hot and ground and 120 between phases. You would treat this like a 240 volt only system in the US just running instead on 120.

A 3rd possibility is a TT type system. On this system the utility does not supply a ground wire or one to use as a ground and thus the customer relies on his own grounding grid. The neutral however (if present) is grounded at the utility transformer; but in any case you need GFCI/RCD protection for faults to be cleared since the customer's ground grid may have a resistance to high to trip a normal breaker under a fault. If you do have a TT system the readings are most likely from a fault somewhere energizing the grounding grid/system.

 

[Besoeker]

In Norway the norm is ungrounded 230volt for residential and commercial, 690volt ungrounded for heavy industrial ect. The wye XO at the transformer is often left floating but grounded through a surge arrester that will short to ground when there is a fault such as high voltage going into the low (ie, transformer winding crossing).

See page 14: http://www.elsif.no/fileadmin/Dokumenter/Hoyspenningsrapport.pdf

Not really useful for those who can neither read nor understand Norwegian.

sale[/B]: http://www.el-tjeneste.no/files/Brosjyre-Nullpunktsikring.pdf

If you want to promote products I suggest you contact admin before you do so.

 

[mbrooke]

Not really useful for those who can neither read nor understand Norwegian.

I am fully aware they are in Norwegian, but they do have pictures that are universally seen and understood. There are also free online language translators that can be used if one is curious about a word or sentence via cut and paste. Electrical theory is universal concept that I am aware of, and many want to extend their understanding.


If you want to promote products I suggest you contact admin before you do so.

How did you reach the conclusion I am promoting a product just by me giving an example that something exists, especially something that cant be bought or used by any of us on this forum? Its no different than those who post spec sheets or product literature for educational purposes or to clear up confusion, there will always be a name behind who published it.

 

[Besoeker]

How did you reach the conclusion I am promoting a product just by me giving an example that something exists.

Maybe "And the surge arrester for sale"

 

[mbrooke]

Maybe "And the surge arrester for sale"

Ok I should have phrased it differently, but I was referring to what is normally required to be used by code in a different part of the world.

 

[Besoeker]

Ok I should have phrased it differently, but I was referring to what is normally required to be used by code in a different part of the world.

Finegood.
It just didn't come across that way.
If I misinterpreted it, I apologise.

 

[mbrooke]

Finegood.
It just didn't come across that way.
If I misinterpreted it, I apologise.

Its ok dont worry about. Im just not to thrilled with the voltages the OP is getting to ground, Im hope its nothing dangerous.