Transformer multiple high legs question

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weather77

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What would cause multiple high 191 volt readings on 3 phase 120/208 panel?
Feed from 3 phase 277/480 panel in small retail space.
It had water leak and now receptacles/ switches are reading 191 volts on multiple legs

Is this a transformer problem or bad leg on high side?
 
If you are reading 191 to ground or neutral from all legs and there is no overcurrent anywhere, then possibly the wye point to neutral connection or some/all of the phase connections have opened up and all you are reading is phantom voltage. What happens when you try to feed a phase to neutral load? (Don't try that with a motor!)

You know there is a transformer in the picture, so measure/inspect at its primary and secondary. Look for fuses too if the secondary to panel run is not a tap.

Tapatalk!
 
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reading 191 all legs to neutral and ground

reading 214 between phases

The bath room fan was running fast. the light was burning out

We were called because items plugged into wall sockets were making popping noises

Could this be a bad breaker leg feeding the transformer?
 
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Is the secondary bonded properly?

Your 214 phase to phase reading kind of tells me nothing is likely wrong with the transformer or the supply, though I would expect some more imbalance in the phase to neutral voltages but am not giving up on a grounding/bonding issue just yet.

Are you measuring to a "true neutral" or something that is "floating" though it appears to be the neutral, or are you measuring to an EGC that is not bonded to the neutral back at the source or first disconnecting means?
 
The only way to get that high of voltage to neutral on all three phases if if you aren't reading to neutral at all, just phantom voltage as stated above. Check for continuity from the source neutral to the load neutrals. Sounds like a missing neutral to me.
 
meternerd said:
The only way to get that high of voltage to neutral on all three phases if if you aren't reading to neutral at all, just phantom voltage as stated above. Check for continuity from the source neutral to the load neutrals. Sounds like a missing neutral to me.
Click to expand...

And probably with no connected loads to neutral either, if there were connected loads the voltages would either be balanced at 120 if the loads were balanced, or you would see variances in voltage according to what unbalance there is in the loads, but if all three voltages are balanced at the wrong level - probably an unloaded open neutral and reading some capacitive coupling. Use of a low impedance meter may very well give different readings as well here.

I'd bet if the OP connected three equal 120 volt loads from each phase to neutral and then took readings they would come out very near 120 volts, but adding unbalanced load afterward would throw the voltage balance off.
 
I was just testing at the panel itself.

Sounds like a lost neutral, Phantom voltage

This all came about after water leak above transformer.

If i go back ill report what the fix was

thanks everybody.
 
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