480Y/277V, 208Y/120V

[anbm]

Is the neutral to ground voltage in 480Y/277V and 208Y/12OV systems supposed to be 0? What happen if it is greater than 0? What is possible problem?

Thank you!

 

[iwire]

If there is any load on the system it will not be 0 due to voltage drop.

However is the difference starts exceeding say about 5 volts on a 120 circuit you may have other issues like open or unbonded neutrals.

 

[anbm]

Is there a limitation for N-G voltage by NEC? Other Codes?

 

[charlie b]

Is the neutral to ground voltage in 480Y/277V and 208Y/12OV systems supposed to be 0?

At what point in the system? Presuming this is a grounded system, the voltage will be zero at whatever location (often the service panel) that you make the N-G bond. At any other location, as Bob pointed out, there will be some voltage drop along the neutral wire, and there will not be a similar voltage drop in the ground wire, so there will be a difference in potential (however small) between neutral and ground.

 

[anbm]

If there is any load on the system it will not be 0 due to voltage drop.

However is the difference starts exceeding say about 5 volts on a 120 circuit you may have other issues like open or unbonded neutrals.

If N-G voltage on 120V circuit is 11V (by metering), will this be a voltage drop issue?

 

[iwire]

If N-G voltage on 120V circuit is 11V (by metering), will this be a voltage drop issue?

I would say that is excessive and I would look into it more.

 

[Dave Brenchley]

Just curious as I dropped by .. isn't this situation called a ground loop ?

 

[Electric-Light]

The ground wire acts as a sensing wire in this case.

The voltage between N and G should be 1/2 of voltage drop.

 

[iwire]

Just curious as I dropped by .. isn't this situation called a ground loop ?

No