Hot to ground too High

[Pavco Electric]

My company builds Jersey mikes sandwiches stores throughout southern Cali We got a service call GFCI outlets keep burning out During testing we found:
Hot to Neutral 120 volts
Hot to ground 200 Volts
Any Ideas on what could cause this ?

 

[hillbilly1]

Is the service 480? And has a customer owned step down transformer? XO not bonded, and a fault to ground on one of the phases. Check all phases to ground, and phase to phase.

 

[Pavco Electric]

It is 120/208 volt panel

 

[Pavco Electric]

The problem was the bread oven appliance something in the internal components was sending 200 volts back to the panel on the ground we disconnected the bread oven and everything went back to normal Thanks

 

[tom baker]

Thank you for the follow up

 

[Pavco Electric]

There is other sensitive equipment in the store but for some odd reason the 200 volts to ground was only burning up GFCI devices on the one circuit

 

[Pavco Electric]

This reminds me of a job I did about a year ago. It was a large multi million dollar house that the electricity was acting crazy I had never seen anything like it. I was even having issues at the pool house that was a different structure different panel. We were trying to figure out what happened and passed by an old garage fridge that was making a unforgettable noise we unplugged it and all the issues were gone

 

[don_resqcapt19]

The problem was the bread oven appliance something in the internal components was sending 200 volts back to the panel on the ground we disconnected the bread oven and everything went back to normal Thanks

That should not be possible if the main bonding jumper is installed

There is other sensitive equipment in the store but for some odd reason the 200 volts to ground was only burning up GFCI devices on the one circuit

That also should not be possible as the GFCI device only sees the voltage between the hot and the neutral.

Something else is going on here.

 

[augie47]

Is the source of the power directly from a power co. transformer or is it fed from a distribution room such as in a mall ?

 

[Little Bill]

How could 200V come back on a 120V circuit? I'm assuming 120V GFCI, unless it was a 2-pole GFCI breaker.

 

[roger]

It is 120/208 volt panel

But is that the service voltage or is the answer to Hillbilly1's question yes?

 

[ptonsparky]

Kind of sounds like the wye center point is not earthed. Grounded.

 

[Strathead]

Not buying your "solution." This is very simple. Draw it out. You have an open neutral somewhere. Next step. Check hot to hot. 208 or240 volts means shared neutral with another phase coming in. 120v same phase and likely same circuit. You have to start by finding where the neutral starts sharing with the neutral for the oven. Could be a miswired box. I am assuming the bread oven is 120 volts. but even if it is 208 volts, if it was sending 200 volts back across the neutral, that current would go back to the service on the neutral, it would loop back out of a panel to a GFCI on another circuit.

 

[Jraef]

Kind of sounds like the wye center point is not earthed. Grounded.

What I was thinking... the oven has 3 phase heaters in a Wye, but they fed it single phase and didn't know what to land on the 3rd terminal, so they connected it to ground, something oddball and screwy like that.

 

[petersonra]

My company builds Jersey mikes sandwiches stores throughout southern Cali We got a service call GFCI outlets keep burning out During testing we found:
Hot to Neutral 120 volts
Hot to ground 200 Volts
Any Ideas on what could cause this ?

Open neutral somewhere