Natfuelbilll
Senior Member
NW 3000A Breaker 6.0P Drawout Indoor Dry Location
This is a 3000A breaker between a four generator bus system (each with individual 800A generator breakers) and tied to the load side of a utiltiy fed 3000A breaker (grid parallel).
We have had three GF trip events. One a couple of years ago, and the last two within the last two months.
The trip amp details on phases A/B/C of a ground fault trip event were exactly 300/1200/1200, another were 300/1200/1200 and the latest trip event at 600/1200/1200. These values seem to me to be too precise, too repetitive, too fractionally proportional to the breaker trip rating. i.e.: exactly 1/10th, exactly 1/5th and exactly 2/5ths. It seems unlikely to me that an actual ground fault would provide these repeatable fractional values. The breaker ground fault trip setting is now 500A.
Also, the trip events had no trip date.
300/1200/1200 no trip date
300/1200/1200 no trip date
600/1200/1200 no trip date
The Time/Date screen has correct data
Talked to SquareD - they can't explain the readings.
SquareD Quote #1 is to go over the breaker and wiring $$
SquareD quote #2 is to study the power system for multiple NG connections and adjust GF amp values. $$$
Do you think the recorded amp values are correct?
Did I have a GF?
Here, I'll give some of my hair that I have pulled out.
This is a 3000A breaker between a four generator bus system (each with individual 800A generator breakers) and tied to the load side of a utiltiy fed 3000A breaker (grid parallel).
We have had three GF trip events. One a couple of years ago, and the last two within the last two months.
The trip amp details on phases A/B/C of a ground fault trip event were exactly 300/1200/1200, another were 300/1200/1200 and the latest trip event at 600/1200/1200. These values seem to me to be too precise, too repetitive, too fractionally proportional to the breaker trip rating. i.e.: exactly 1/10th, exactly 1/5th and exactly 2/5ths. It seems unlikely to me that an actual ground fault would provide these repeatable fractional values. The breaker ground fault trip setting is now 500A.
Also, the trip events had no trip date.
300/1200/1200 no trip date
300/1200/1200 no trip date
600/1200/1200 no trip date
The Time/Date screen has correct data
Talked to SquareD - they can't explain the readings.
SquareD Quote #1 is to go over the breaker and wiring $$
SquareD quote #2 is to study the power system for multiple NG connections and adjust GF amp values. $$$
Do you think the recorded amp values are correct?
Did I have a GF?
Here, I'll give some of my hair that I have pulled out.