Ground Fault Issue

[ptonsparky]

You have current flow. It's just not going where you want it. It is a fault to ground/earth.

 

[LarryFine]

When we energized the circuit it popped the 400A breaker at the MDP. When reset, the 400A breaker stated a GF had occurred.

Are you saying that a 400+ amp trip occurred, or that a GFCI-trip occurred?

 

[Fred B]

The current is in the voltage leaking to ground! Example: you have a water hose connected to a sprayer, the sprayer is off (load) you put a hole in the hose, water comes out (current) because you still have the spigot on (main, or breaker for the feeder)

I like that analogy. Going to use that one.

 

[Opie11]

Thanks for all the feedback.
I understand there is a "leak" somewhere, thanks Hillbilly1 for that explanation.
Started meggering yesterday and will continue today.
LarryFine - a 400A breaker tripped at the MDP. Once reset, the breaker screen stated it was a GF so I would say the latter. I believe this breaker to be the only GF protection that exists.

 

[ptonsparky]

Thanks for all the feedback.
I understand there is a "leak" somewhere, thanks Hillbilly1 for that explanation.
Started meggering yesterday and will continue today.
LarryFine - a 400A breaker tripped at the MDP. Once reset, the breaker screen stated it was a GF so I would say the latter. I believe this breaker to be the only GF protection that exists.

What are the settings of that breaker? Pictures?

 

[jim dungar]

A Ground Fault Circuit Interrupter (GFCI) has current coils that monitors the incoming and outgoing currents. When they don't match, the current is going elsewhere, so it trips.

If this is a 480V feeder breaker it does not have GFCI. It's GFP function is usually built using an internal set of CTs and an external neutral CT.

I would look at the neutral CT and its wiring.

 

[ptonsparky]

OP: Is this new or existing?

 

[don_resqcapt19]

Mtnelect - correct. I believe I stated such in my original blurb.
Hillbilly1- so you are saying i do not need current for a GF?

You do not need load current for a ground fault trip on the feeder breaker. You just need current flowing from an energized conductor outside of the normal path. Often, on a grounded system in a wet location, this path can be from an insulation defect, through the earth, and back to the source.

 

[ptonsparky]

We have found them in PVC so don't discount that.

 

[Opie11]

This is an older installation. Do not know what the settings are.
It is 480v.
Don_resqcapt19 - thanks for the explanation.
Been meggering all morning. Found a section between 2 hand holes that is no good. Not sure why yet other than the megger reading. Yes it is in PVC.

 

[hillbilly1]

This is an older installation. Do not know what the settings are.
It is 480v.
Don_resqcapt19 - thanks for the explanation.
Been meggering all morning. Found a section between 2 hand holes that is no good. Not sure why yet other than the megger reading. Yes it is in PVC.

You will know when you pull that wire out. It will be very obvious.