Voltage Issue

[MCushing19]

I have a service call where an instant water heater keeps burning the elements. I have an issue I have not seen before I don't necessarily believe its the problem but am concerned about it. I have a 45 KVA 480 volt delta to 120/208 Y transformer. At my main breaker in my 120/208 volt panel I am getting A-B 209 volts B-C 211 volts C-A 211 volts, A-Neutral 120 volts B-Neutral 120 volts C-Neutral 120 volts, A-Ground 132 Volts B-Ground 120 volts and C-Ground 120-volts. My heater is on A phase and I don't understand why I am getting 132 volts from hot to ground.? I have not been able to open the transformer but I am not sure it is a bonding problem? Any ideas?

 

[ptonsparky]

I have a service call where an instant water heater keeps burning the elements. I have an issue I have not seen before I don't necessarily believe its the problem but am concerned about it. I have a 45 KVA 480 volt delta to 120/208 Y transformer. At my main breaker in my 120/208 volt panel I am getting A-B 209 volts B-C 211 volts C-A 211 volts, A-Neutral 120 volts B-Neutral 120 volts C-Neutral 120 volts, A-Ground 132 Volts B-Ground 120 volts and C-Ground 120-volts. My heater is on A phase and I don't understand why I am getting 132 volts from hot to ground.? I have not been able to open the transformer but I am not sure it is a bonding problem? Any ideas?

Your load is connected A to neutral. That is the applied voltage. Not A to Ground . As long as A-N stays within parameters you should be good there.

 

[winnie]

The A-ground voltage is strange and may indicate a problem someplace else in the system. The different A-N and A-G voltages suggest that something is not bonded correctly.

As ptonsparky says, however, this probably has nothing to do with burning up elements...but is not totally ignorable.

-Jon

 

[zbang]

Usually when one of those is burning out the elements, either the flow switch or thermostat is defective.