Different phase to ground voltage readings

Status
Not open for further replies.
Besoeker said:
It has ro do with unbalanced voltages. I offered a simple test to determine that.
Click to expand...

No, that is your spin on it. This is the subject of the thread as stated in the title.

"Different phase to ground voltage readings"



I will say it again

In this case all the readings from line to neutral will be normal. You would find no evidence of a the problem by taking line to neutral readings. It is not possible.
 
Here are the pics of the XMFR , inside and out. The enclosure and bare ground wire for both the Primary and Secondary cables are connected to earth ground. My question is do I need to bond the XO leads from the XFMR to earth ground, via the enclosure, to solve my problem?
bea240ff89778b215e2b37ac8e4dbde8.jpg
ee11990dd00ae8d8dac395be9b36f6e1.jpg


Sent from my VS986 using Tapatalk
 
kmartinez5588 said:
Yes, the neutral is connected to the XO. The neutral to ground voltage is 120V

Sent from my VS986 using Tapatalk
Click to expand...

Please confirm your wiring and all 10 of the possible voltage combinations.

If X0 is connected to Ground, you should not be reading 120V.
If X0 is not connected to ground, then all voltages referencing ground are basically meaningless.
 
GoldDigger said:
And the neutral is connected to X0?????
What we need to see is secondary hot to XO. If those are not equal possibly the primary taps are not set properly.

Sent from my XT1585 using Tapatalk
Click to expand...
If they are what tey are purported to be I would have there would be equipment failing.
Anything expecting 120V single phase and getting L1 -N 203V would surely fry. Rather quickly.
On that basis, I have doubts about what is actually being measured.
 
jim dungar said:
Please confirm your wiring and all 10 of the possible voltage combinations.

If X0 is connected to Ground, you should not be reading 120V.
If X0 is not connected to ground, then all voltages referencing ground are basically meaningless.
Click to expand...

I quite agree. That's what I was trying to explain to your fellow mod.
And, per post #2, we don't even know if there is a ground.
 
Besoeker said:
I quite agree. That's what I was trying to explain to your fellow mod.
And, per post #2, we don't even know if there is a ground.
Click to expand...
We see to be fairly certain there is no bond between neutral and "ground". However phase to neutral voltages are not quite right either and we haven't figured out why just yet.
 
kwired said:
We see to be fairly certain there is no bond between neutral and "ground". However phase to neutral voltages are not quite right either and we haven't figured out why just yet.
Click to expand...
No, not right by a big margin which is why I called in question the readings. Stuff would have fried.
 
Besoeker said:
No, not right by a big margin which is why I called in question the readings. Stuff would have fried.
Click to expand...
Unless maybe there is no line to neutral loads. Things like 120-277 electronic lighting ballast may just adjust itself to the new voltage as well.
 
kwired said:
Unless maybe there is no line to neutral loads. Things like 120-277 electronic lighting ballast may just adjust itself to the new voltage as well.
Click to expand...
Possibly there are no line to neutral single phase loads.
That still doesn't account for the huge disparity in line to neutral voltages. Nor the 203V L1- N when it is nominally 120V. That's why I suspect the validity of the measurements.
 
ptonsparky said:
You are being very polite in your suspions.
Click to expand...
Mods be kind please.
I try to be at least civil. That can be a bit of a challenge at times when someone tells me I don't understand power.

Back on topic.......
I don't believe that the transformer depicted could output the phase to neutral voltages stated. The only explanation I can offer is that it wasn't phase to neutral that was measured.
 
Besoeker said:
I don't believe that the transformer depicted could output the phase to neutral voltages stated. The only explanation I can offer is that it wasn't phase to neutral that was measured.
Click to expand...
I have to agree with that, or something is seriously wrong or misconnected, but such things have a higher probability of letting smoke out as well.
 
Here are my readings from the first main panel:
L1-L2 = 202v
L1-L3 = 202v
L2-L3 = 202v
L1-N = 117v
L2-N = 117v
L3-N = 117v
L1-GND = 151v
L2-GND = 250v
L3-GND = 96v
N-GND = 136v
The XFMR is grounded to earth, along with the bare ground wires from both the Primary and Secondary feeds. Does this sound like an ungrounded system? The xmfr is primarily used for lighting and feeds several subpanels from the main panel.

Sent from my VS986 using Tapatalk
 
kmartinez5588 said:
Here are my readings from the first main panel:
L1-L2 = 202v
L1-L3 = 202v
L2-L3 = 202v
L1-N = 117v
L2-N = 117v
L3-N = 117v
L1-GND = 151v
L2-GND = 250v
L3-GND = 96v
N-GND = 136v
The XFMR is grounded to earth, along with the bare ground wires from both the Primary and Secondary feeds. Does this sound like an ungrounded system? The xmfr is primarily used for lighting and feeds several subpanels from the main panel.

Sent from my VS986 using Tapatalk
Click to expand...

Without a doubt you are missing an NEC required bonding jumper from XO to the equipment grounding terminal.


Once the jumper is installed you may find you have a short circuit to chase down as well. But first get that jumper installed.
 
Status
Not open for further replies.
Top