The weakest link

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ronaldrc

Senior Member
Location
Tennessee
Maybe I am reading the post wrong but the way I am reading it they are wondering why the smaller breaker didn't trip instead of the 1600.

I' m think the 1600 tripped because of the lower Ic rating of the main breaker and not the GFI protection built into the main.

If it tripped because it seen a ground fault from the GFI I would agree with you but I dont think they said that?

If it did tripped from seeing a small ground fault from the GFI equipment protection on the breaker then Don was right, no it wouldn't be reflected back through the motor drive. :)
 

Smart $

Esteemed Member
Location
Ohio
ronaldrc said:
Maybe I am reading the post wrong but the way I am reading it they are wondering why the smaller breaker didn't trip instead of the 1600.

I' m think the 1600 tripped because of the lower Ic rating of the main breaker and not the GFI protection built into the main.

If it tripped because it seen a ground fault from the GFI I would agree with you but I dont think they said that?

If it did tripped from seeing a small ground fault from the GFI equipment protection on the breaker then Don was right, no it wouldn't be reflected back through the motor drive. :)
I read the OP as saying a ground fault tripped the main. The part where it is written "(ground fault flag pop out") is what I'm referring to.
 

brian john

Senior Member
Location
Leesburg, VA
Randomnly jerking around settings without a full understanding of what you are doing and the resulting liability is a MAJOR mistake in my book.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
ronaldrc said:
I' m think the 1600 tripped because of the lower Ic rating of the main breaker and not the GFI protection built into the main.

The AIC rating of a circuit breaker has no effect on how fast it "decides to trip"
 

mayanees

Senior Member
Location
Westminster, MD
Occupation
Electrical Engineer and Master Electrician
NEC limit on GF

NEC limit on GF

brian john said:
Randomnly jerking around settings without a full understanding of what you are doing and the resulting liability is a MAJOR mistake in my book.
There is enough information from the OP to determine the appropriate NEC compliant GF settings for the system described - and they are currently set too low.
Adjustment to the NEC allowable limits listed in my first response will only improve the coordination performance of the system.
JM
 
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