One detail missing.

[ptonsparky]

In another thread about imbalanced voltages and currents the POCO decided to change a corner grounded delta well service to a delta with high leg.

They based it on current measurements they took at the pole after checking and cleaning all connections.
Measuring current of the grounded conductor at load side of the meter socket gave them 38 amps. Amps at the mast head just below transformers was about 30. Same leg. Removing the pole ground increased the mast head current. What detail were they missing that added to their confusion?

 

[Another C10]

What detail were they missing that added to their confusion?

Did they inadvertently move the bond to the structures earth ground by removing the utility pole bond. or was there less resistance of the poles ground than that of the structures ground.

 

[oldsparky52]

I'm not sure I really understand. The service drop (or lateral) was 3 wire Delta and corner grounded at the service disconnect only? Then the new configuration was a Delta high leg, so ... a grounded conductor was added to the service drop (or lateral)?

And someone made sure the existing corner grounded was reconfigured to insure the grounding was correct for the new configuration? I'm a little hard headed sometimes, sorry if I don't get it right away.

 

[ptonsparky]

The structure for Ag Pump Panels in this area are the PPs mounted on posts, but their mistake was what was occurring at thevpolat the pole

 

[ptonsparky]

I'm not sure I really understand. The service drop (or lateral) was 3 wire Delta and corner grounded at the service disconnect only? Then the new configuration was a Delta high leg, so ... a grounded conductor was added to the service drop (or lateral)?

And someone made sure the existing corner grounded was reconfigured to insure the grounding was correct for the new configuration? I'm a little hard headed sometimes, sorry if I don't get it right away.

The original instal was corner ground with bond at meter socket, with four wire lateral wire to PP.

The reason they used to change it to high leg delta, were the current readings they took at the pole. What did they do wrong, or miss when they took the current readings?

What I think is a perfectly clear explanation, is not. So I am reminded by my spouse often enough.

 

[oldsparky52]

The original instal was corner ground with bond at meter socket, with four wire lateral wire to PP.

The reason they used to change it to high leg delta, were the current readings they took at the pole. What did they do wrong, or miss when they took the current readings?

What I think is a perfectly clear explanation, is not. So I am reminded by my spouse often enough.

Well once again I'm not smart enough to figure it out so I'll wait for the explanation.

 

[hillbilly1]

If I am reading it correctly, the poco was creating a parralell path for that phase by bonding it at the pole, and at the service. When they lfted the bond at the pole, it removed that parralell path. The readings they were taking at the pole were probably after the transformer bond. That explains why the amps went up when the bond at the pole was removed. The 8 amps was was using the earth and other means to return such as a metal well casing to the pocos ground field.

 

[ptonsparky]

If I am reading it correctly, the poco was creating a parralell path for that phase by bonding it at the pole, and at the service. When they lfted the bond at the pole, it removed that parralell path. The readings they were taking at the pole were probably after the transformer bond. That explains why the amps went up when the bond at the pole was removed. The 8 amps was was using the earth and other means to return such as a metal well casing to the pocos ground field.

Close enough.

The xfmr bank and meter were mounted on a metal pole.

The pole ground was made via 6 bare from meter grounded terminal to lug on pole. Lifting that pole ground removed the parallel path. Odd that the meter socket mounting screws did not carry that load, but they did not. They may have carried some, but the techs were vague on numbers.

Not understanding the parallel path gave them reason to change the system to hi leg delta.

eta: IDK if they understood or believed me when I tried to explain it. Tried being the key word.

 

[hillbilly1]

Close enough.

The xfmr bank and meter were mounted on a metal pole.

The pole ground was made via 6 bare from meter grounded terminal to lug on pole. Lifting that pole ground removed the parallel path. Odd that the meter socket mounting screws did not carry that load, but they did not. They may have carried some, but the techs were vague on numbers.

Not understanding the parallel path gave them reason to change the system to hi leg delta.

They were losing money, thats why. That current was bypassing the meter!
Lol!

 

[Another C10]

If I am reading it correctly, the poco was creating a parralell path for that phase by bonding it at the pole, and at the service. When they lfted the bond at the pole, it removed that parralell path. The readings they were taking at the pole were probably after the transformer bond. That explains why the amps went up when the bond at the pole was removed. The 8 amps was was using the earth and other means to return such as a metal well casing to the pocos ground field.

That was pretty much what I said in post #2 but maybe it wasn't clear , it was just a educated theory.

 

[ptonsparky]

That was pretty much what I said in post #2 but maybe it wasn't clear , it was just a educated theory.

Well dang, you win a prize, too.

I judge about as well as I explain.

 

[Another C10]

Well dang, you win a prize, too.

Thank you, I may not of been as accurate as hillbilly but ... I was somewhat close. on a friendlier note, its always nice to be acknowledged even if ones wrong .. I enjoy reading from all you folks, a lot of smart people in here.