GEC

[DBoone]

I understand that if someone is grounded and touches an ungrounded conductor current will travel thru said person, thru the earth, and up the GEC at the utility pole to the transformer. If the GEC at the transformer and the GEC at the service equipment are disconnected how does the current return to its source when someone touches an ungrounded conductor.

 

[GoldDigger]

I understand that if someone is grounded and touches an ungrounded conductor current will travel thru said person, thru the earth, and up the GEC at the utility pole to the transformer. If the GEC at the transformer and the GEC at the service equipment are disconnected how does the current return to its source when someone touches an ungrounded conductor.

It does not, since you now have an ungrounded system. In a residential installation the same secondary neutral may be grounded at other houses though. In which case you will get zapped through that path.

 

[DBoone]

For example if a transformer serves two homes and the neutral is grounded at the transformer and the SE of each home, if we disconnect the GEC at the transformer and House 1 the current would return to the source by way of the House 2 neutral?

 

[GoldDigger]

For example if a transformer serves two homes and the neutral is grounded at the transformer and the SE of each home, if we disconnect the GEC at the transformer and House 1 the current would return to the source by way of the House 2 neutral?

Yes. Flowing either through the earth or metal pipes or whatever is available to get from one GES to the other.

 

[cowboyjwc]

Yes. Flowing either through the earth or metal pipes or whatever is available to get from one GES to the other.

Path of least resistance.

 

[GoldDigger]

Path of least resistance.

Paths of least resistance. It will not necessarily follow just one. That causes problems for a lot of people too.

 

[mgookin]

Paths of least resistance. It will not necessarily follow just one. That causes problems for a lot of people too.

All paths! The one with least resistance gets greatest magnitude of power, but it still follows all paths.

That's the only way an electronic circuit can work.

 

[hurk27]

I understand that if someone is grounded and touches an ungrounded conductor current will travel thru said person, thru the earth, and up the GEC at the utility pole to the transformer. If the GEC at the transformer and the GEC at the service equipment are disconnected how does the current return to its source when someone touches an ungrounded conductor.

Besides what others have said, even disconnecting the GEC's at a building and the pole you can also have other paths to Earth from other electrodes down the road, if the transformers secondaries are connected to the MGN (multiple grounded neutral) at the pole this neutral can have other electrodes at other poles or other services, most utility's ground the MGN 4 times per mile as well as at each transformer or switch.

 

[electrofelon]

Besides what others have said, even disconnecting the GEC's at a building and the pole you can also have other paths to Earth from other electrodes down the road, if the transformers secondaries are connected to the MGN (multiple grounded neutral) at the pole this neutral can have other electrodes at other poles or other services, most utility's ground the MGN 4 times per mile as well as at each transformer or switch.

Let's just be careful and note that a MGN is not universal. Some utilities I work with have lots of delta distribution ( thinking of nyseg In central ny in particular)

 

[ptonsparky]

Isn't there a problem with capacitance as well?
Static discharge.

 

[kwired]

Besides what others have said, even disconnecting the GEC's at a building and the pole you can also have other paths to Earth from other electrodes down the road, if the transformers secondaries are connected to the MGN (multiple grounded neutral) at the pole this neutral can have other electrodes at other poles or other services, most utility's ground the MGN 4 times per mile as well as at each transformer or switch.

I agree, the GEC at the transformer is just one point along a system that is likely earthed many times, so the system is still "grounded" someplace.

Take a true ungrounded system and introduce a ground fault, nothing out of the ordinary happens operation wise, but it effectively becomes a grounded system with the fault point being the grounding reference point.