Ground Fault

[josh111]

I am using a ground fault sensor in conjunction with a controller to protect from stator ground fault on a generator. I have come across several that say they are rated at 10, 20 and so on amps. (the system shuts down only when stator ground fault occurs.)

What I am wondering is what would happen when the current is overloaded beyond what the CT switch is rated at. If you look at the diagram it will show that very high currents can flow while in many other ground fault applications, it is only small fault currents that will flow. Will the saturation cause a regular ground fault CT to be damaged?

Do I need to consider something else for what I am doing?

There is a diagram posted on this web site:
http://forum.allaboutcircuits.com/sh...ad.php?t=32061

[wellandpower]

Josh,

Any CT can burn out if it is overloaded.
As you rightly say, when an earth fault happens, there is a sudden rush of current.

The difference between the earth fault current and "normal" current through a CT is that the earth fault system is designed to detect a current flowing and stop the set. This means that in practise if the earth fault trip is not set too high the detection will trip the breaker and shutdown the set before the CT burns.